| --- |
| license: cc-by-nc-4.0 |
| task_categories: |
| - robotics |
| - image-to-3d |
| language: |
| - en |
| tags: |
| - vitra |
| - mano |
| - hand-object-interaction |
| - bimanual |
| --- |
| |
| # arctic-annotations-v1 |
|
|
| **Annotations only — no images, no video.** |
|
|
| VITRA-style hand episodes for **ARCTIC**, with per-hand instructions and paraphrases. |
|
|
| | | | |
| |---|---| |
| | episodes | **12,610** | |
| | training samples (`index_frame_pair` rows) | **425,796** | |
| | annotation | MANO pose + world/camera joints + per-frame extrinsics | |
| | text | one instruction per episode + 1.86 paraphrases on average | |
| | source frame rate | 30 fps | |
| | **images / video** | **not included** — see *Getting the frames* below | |
|
|
| ARCTIC is the one dataset here that was **built for two-handed manipulation of articulated |
| objects** — 11 objects with moving parts, captured while both hands operate them together. |
|
|
| ### What we did |
|
|
| **Episodes are ours.** The source release ships either raw video or differently-segmented |
| clips, so we re-cut it with VITRA's method — speed minima of the 3D wrist in world space: |
|
|
| gaussian smooth (sigma=1.0) -> local speed minima in a fixed window (win=15, i.e. 0.5 s |
| at 30 Hz) -> merge runs shorter than min_seg=16 -> pad 2 frames on each end |
| |
| sigma and win are quantities in *time*, converted per source frame rate. Left and right hands |
| are cut independently, with the other hand's motion ignored. |
|
|
| **Instructions are ours.** Two rounds, both with `Qwen3.5-122B-A10B-FP8`: |
| round 1 captions 8 frames per episode with the palm's future trajectory drawn on them; |
| round 2 checks the sentence belongs to that hand, strips same-hand references |
| ("Rinse the right hand." -> "Rinse the hand.", because training already prepends |
| `Left hand: ... Right hand: ...`), and writes 1-3 paraphrases. |
|
|
| **Episodes with no instruction are not included.** Round 1 returns `N/A` when an episode |
| shows no object interaction. Those episodes are excluded from both the archive and the |
| index, so every episode here has a usable instruction. |
|
|
| ### Egocentric view only |
|
|
| ARCTIC records each sequence from **8 static cameras plus one head-mounted egocentric camera**. |
| Only the egocentric view is here; we train on head-mounted footage. |
|
|
| The public release covers **301 sequences from 9 subjects** (the paper reports 393 from 10; |
| `s03` is withheld for the official test server), which is what these episodes are cut from. |
|
|
| One practical note if you fetch the images: ARCTIC's `cropped` image package does **not** crop |
| the egocentric view. `scripts_data/crop_images.py` crops only views 1-8 to 1000x1000 around the |
| object; view 0 is the full frame resized by `EGO_IMAGE_SCALE = 0.3`, giving **840x600** with the |
| geometry intact. Scale the intrinsics by 0.3 and they match — there is no need for the 649 GB |
| full-resolution package. |
|
|
| ### Three conventions we converted, and why |
|
|
| Values here follow the same conventions as the other repos in this collection, which differ from |
| ARCTIC's raw MANO parameters in three places. All three were measured, not assumed: |
|
|
| - **`transl_worldspace` is the wrist joint**, obtained by running MANO forward and taking |
| `joints[0]`. ARCTIC's raw `trans` is **not** the wrist — it sits 9.23 cm (right) / 9.27 cm |
| (left) away from it. |
| - **`hand_pose` has `hands_mean` added back.** Round-tripping with it reproduces ARCTIC's own |
| joints to 0.000000 cm. |
| - **The left hand uses a genuine `MANO_LEFT` model**, not a mirrored right hand. |
|
|
| Also checked: 21-joint bone-length CV is 0.00000 (joint order matches ours), median bone length |
| 27.8 mm (TACO 28.2, EPIC 29.0), `extrinsics` deviate from orthonormal by 8.1e-07, and MANO frame |
| counts equal egocentric frame counts on every sequence tested. |
|
|
| ### Files |
|
|
| ``` |
| arctic.tar -> Annotation/arctic/episodic_annotations/*.npy |
| episode_frame_index.npz index_frame_pair (N,2) uint32 + index_to_episode_id (E,) |
| ``` |
|
|
| `index_frame_pair` **row number is the sample id**: row r = (episode ordinal, frame within |
| that episode). `len(index_frame_pair)` is the size of the training set. |
|
|
| ```python |
| import numpy as np |
| # tar -xf arctic.tar |
| z = np.load("episode_frame_index.npz", allow_pickle=True) |
| ep_slot, frame_id = z["index_frame_pair"][sample_id] |
| eid = str(z["index_to_episode_id"][ep_slot]) |
| d = np.load(f"Annotation/arctic/episodic_annotations/{eid}.npy", allow_pickle=True).item() |
| rgb_frame_id = int(d["video_decode_frame"][frame_id]) |
| ``` |
|
|
| Each `.npy` is a dict with `video_name`, `video_decode_frame`, `intrinsics`, |
| per-frame `extrinsics` (world->camera), `anno_type` (which hand this episode is for), |
| `text`, `text_rephrase`, and a `left`/`right` dict holding `beta`, `hand_pose`, |
| `global_orient_worldspace`, `transl_worldspace`, `joints_worldspace`, `kept_frames`. |
| `text[hand] = [(sentence, (0, T))]` and `text_rephrase[hand] = [([paraphrases...], (0, T))]`. |
|
|
| ### Getting the frames |
|
|
| `video_decode_frame` indexes the **source** video, which we do not redistribute. |
| Get it from ARCTIC — https://arctic.is.tue.mpg.de/, then decode by index (we use `decord`; a |
| self-maintained sequential counter drifts silently if the decoder ever skips a frame). |
|
|
| ### Known limitations |
|
|
| - Paraphrase count averages 1.86, not a fixed number. Past 3 the model starts inventing; |
| a sentence with no prepositional phrase honestly supports only one or two. |
| - ARCTIC is a **lab capture**: a mocap studio, 11 objects, 9 subjects. Its pose quality is the |
| highest here, its visual and task diversity the lowest. It is 2.3 hours of source video. |
| - Verified: the index lists exactly the episodes that have an instruction, every episode's |
| stored frame count matches its index rows, and no index entry points at a missing episode. |
|
|
| --- |
| <!-- COLLECTION_TABLE_START --> |
| | dataset | episodes | training samples | our contribution | size | HF | |
| |---|---:|---:|---|---:|---| |
| | **EPIC-KITCHENS-100** | 149,570 | 4,019,534 | episodes + text | 8.70 GB | [`epic30-annotations-v1`](https://huggingface.co/datasets/MIT-Media-Lab/epic30-annotations-v1) | |
| | **EgoTouch** | 107,364 | 3,123,675 | episodes + text + **tactile** | 17.02 GB | [`egotouch-annotations-v1`](https://huggingface.co/datasets/MIT-Media-Lab/egotouch-annotations-v1) | |
| | **GigaHands** | 70,486 | 2,266,087 | episodes + text | 2.89 GB | [`gigahands-annotations-v1`](https://huggingface.co/datasets/MIT-Media-Lab/gigahands-annotations-v1) | |
| | **Ego-Exo4D** | 67,051 | 1,757,474 | text only | 4.09 GB | [`egoexo4d-annotations-v1`](https://huggingface.co/datasets/MIT-Media-Lab/egoexo4d-annotations-v1) | |
| | **OakInk2** | 29,058 | 1,052,924 | episodes + text | 1.56 GB | [`oakink2-annotations-v1`](https://huggingface.co/datasets/MIT-Media-Lab/oakink2-annotations-v1) | |
| | **TACO** | 23,757 | 736,136 | episodes + text | 1.34 GB | [`taco-annotations-v1`](https://huggingface.co/datasets/MIT-Media-Lab/taco-annotations-v1) | |
| | **HOT3D** | 18,805 | 619,680 | episodes + text | 1.51 GB | [`hot3d-annotations-v1`](https://huggingface.co/datasets/MIT-Media-Lab/hot3d-annotations-v1) | |
| | **ARCTIC** | 12,610 | 425,796 | episodes + text | 0.85 GB | [`arctic-annotations-v1`](https://huggingface.co/datasets/MIT-Media-Lab/arctic-annotations-v1) | |
| | **H2O** | 5,845 | 200,332 | episodes + text | 0.40 GB | [`h2o-annotations-v1`](https://huggingface.co/datasets/MIT-Media-Lab/h2o-annotations-v1) | |
| | **Tachin** | 2,669 | 79,584 | episodes + text + **tactile** | 3.38 GB | [`tachin-annotations-v1`](https://huggingface.co/datasets/MIT-Media-Lab/tachin-annotations-v1) | |
| | **total** | **487,215** | **14,281,222** | | **41.7 GB** | | |
|
|
| > **Something-Something V2 was dropped** from the collection (12 fps against |
| > 30 fps everywhere else, so a 16-step action chunk spans 1.33 s instead of 0.53 s). |
| > The repository still exists but should not be used. |
| <!-- COLLECTION_TABLE_END --> |
|
|
