dataset card

README.md

@@ -1,910 +1,208 @@
 ---
-dataset_info:
-- config_name: frames
-  features:
-  - name: object_id
-    dtype: string
-  - name: pts3d
-    struct:
-    - name: __t__
-      dtype: int64
-    - name: shape
-      list: int64
-    - name: dtype
-      dtype: string
-    - name: data
-      dtype: binary
-    - name: q
-      dtype: string
-    - name: scale
-      dtype: float64
-    - name: pack
-      dtype: string
-    - name: z
-      dtype: string
-    - name: nbytes
-      dtype: int64
-  - name: pts3d_feats
-    struct:
-    - name: __t__
-      dtype: int64
-    - name: shape
-      list: int64
-    - name: dtype
-      dtype: string
-    - name: data
-      dtype: binary
-    - name: q
-      dtype: string
-    - name: scale
-      dtype: float64
-    - name: pack
-      dtype: string
-    - name: z
-      dtype: string
-    - name: nbytes
-      dtype: int64
-  - name: pts3d_feats_mask
-    struct:
-    - name: __t__
-      dtype: int64
-    - name: shape
-      list: int64
-    - name: dtype
-      dtype: string
-    - name: data
-      dtype: binary
-    - name: q
-      dtype: string
-    - name: scale
-      dtype: float64
-    - name: pack
-      dtype: string
-    - name: z
-      dtype: string
-    - name: nbytes
-      dtype: int64
-  - name: verts3d
-    struct:
-    - name: __t__
-      dtype: int64
-    - name: shape
-      list: int64
-    - name: dtype
-      dtype: string
-    - name: data
-      dtype: binary
-    - name: q
-      dtype: string
-    - name: scale
-      dtype: float64
-    - name: pack
-      dtype: string
-    - name: z
-      dtype: string
-    - name: nbytes
-      dtype: int64
-  - name: verts3d_feats
-    struct:
-    - name: __t__
-      dtype: int64
-    - name: shape
-      list: int64
-    - name: dtype
-      dtype: string
-    - name: data
-      dtype: binary
-    - name: q
-      dtype: string
-    - name: scale
-      dtype: float64
-    - name: pack
-      dtype: string
-    - name: z
-      dtype: string
-    - name: nbytes
-      dtype: int64
-  - name: verts3d_feats_mask
-    struct:
-    - name: __t__
-      dtype: int64
-    - name: shape
-      list: int64
-    - name: dtype
-      dtype: string
-    - name: data
-      dtype: binary
-    - name: q
-      dtype: string
-    - name: scale
-      dtype: float64
-    - name: pack
-      dtype: string
-    - name: z
-      dtype: string
-    - name: nbytes
-      dtype: int64
-  - name: mesh
-    struct:
-    - name: __dc__
-      dtype: string
-    - name: fields
-      struct:
-      - name: verts
-        struct:
-        - name: __t__
-          dtype: int64
-        - name: shape
-          list: int64
-        - name: dtype
-          dtype: string
-        - name: data
-          dtype: binary
-        - name: q
-          dtype: string
-        - name: scale
-          dtype: float64
-        - name: pack
-          dtype: string
-        - name: z
-          dtype: string
-        - name: nbytes
-          dtype: int64
-      - name: faces
-        struct:
-        - name: __t__
-          dtype: int64
-        - name: shape
-          list: int64
-        - name: dtype
-          dtype: string
-        - name: data
-          dtype: binary
-        - name: q
-          dtype: string
-        - name: scale
-          dtype: float64
-        - name: pack
-          dtype: string
-        - name: z
-          dtype: string
-        - name: nbytes
-          dtype: int64
-      - name: vert_colors
-        struct:
-        - name: __t__
-          dtype: int64
-        - name: shape
-          list: int64
-        - name: dtype
-          dtype: string
-        - name: data
-          dtype: binary
-        - name: q
-          dtype: string
-        - name: scale
-          dtype: float64
-        - name: pack
-          dtype: string
-        - name: z
-          dtype: string
-        - name: nbytes
-          dtype: int64
-      - name: verts_uvs
-        struct:
-        - name: __t__
-          dtype: int64
-        - name: shape
-          list: int64
-        - name: dtype
-          dtype: string
-        - name: data
-          dtype: binary
-        - name: q
-          dtype: string
-        - name: scale
-          dtype: float64
-        - name: pack
-          dtype: string
-        - name: z
-          dtype: string
-        - name: nbytes
-          dtype: int64
-      - name: faces_uvs
-        struct:
-        - name: __t__
-          dtype: int64
-        - name: shape
-          list: int64
-        - name: dtype
-          dtype: string
-        - name: data
-          dtype: binary
-        - name: q
-          dtype: string
-        - name: scale
-          dtype: float64
-        - name: pack
-          dtype: string
-        - name: z
-          dtype: string
-        - name: nbytes
-          dtype: int64
-      - name: texture
-        struct:
-        - name: __t__
-          dtype: int64
-        - name: shape
-          list: int64
-        - name: dtype
-          dtype: string
-        - name: data
-          dtype: binary
-        - name: q
-          dtype: string
-        - name: scale
-          dtype: float64
-        - name: pack
-          dtype: string
-        - name: z
-          dtype: string
-        - name: nbytes
-          dtype: int64
-      - name: vert_feats
-        struct:
-        - name: __t__
-          dtype: int64
-        - name: shape
-          list: int64
-        - name: dtype
-          dtype: string
-        - name: data
-          dtype: binary
-        - name: q
-          dtype: string
-        - name: scale
-          dtype: float64
-        - name: pack
-          dtype: string
-        - name: z
-          dtype: string
-        - name: nbytes
-          dtype: int64
-  - name: obj_ncds0c_tform4x4_obj
-    struct:
-    - name: __t__
-      dtype: int64
-    - name: shape
-      list: int64
-    - name: dtype
-      dtype: string
-    - name: data
-      dtype: binary
-    - name: q
-      dtype: string
-    - name: scale
-      dtype: float64
-    - name: pack
-      dtype: string
-    - name: z
-      dtype: string
-    - name: nbytes
-      dtype: int64
-  - name: obj_size_ncds
-    dtype: float64
-  - name: obj_size
-    dtype: float64
-  - name: obj_size3d
-    struct:
-    - name: __t__
-      dtype: int64
-    - name: shape
-      list: int64
-    - name: dtype
-      dtype: string
-    - name: data
-      dtype: binary
-    - name: q
-      dtype: string
-    - name: scale
-      dtype: float64
-    - name: pack
-      dtype: string
-    - name: z
-      dtype: string
-    - name: nbytes
-      dtype: int64
-  - name: obj_bbox3d
-    struct:
-    - name: __t__
-      dtype: int64
-    - name: shape
-      list: int64
-    - name: dtype
-      dtype: string
-    - name: data
-      dtype: binary
-    - name: q
-      dtype: string
-    - name: scale
-      dtype: float64
-    - name: pack
-      dtype: string
-    - name: z
-      dtype: string
-    - name: nbytes
-      dtype: int64
-  - name: obj_kpts3d
-    struct:
-    - name: __t__
-      dtype: int64
-    - name: shape
-      list: int64
-    - name: dtype
-      dtype: string
-    - name: data
-      dtype: binary
-    - name: q
-      dtype: string
-    - name: scale
-      dtype: float64
-    - name: pack
-      dtype: string
-    - name: z
-      dtype: string
-    - name: nbytes
-      dtype: int64
-  - name: obj_kpts3d_mask
-    struct:
-    - name: __t__
-      dtype: int64
-    - name: shape
-      list: int64
-    - name: dtype
-      dtype: string
-    - name: data
-      dtype: binary
-    - name: q
-      dtype: string
-    - name: scale
-      dtype: float64
-    - name: pack
-      dtype: string
-    - name: z
-      dtype: string
-    - name: nbytes
-      dtype: int64
-  - name: obj_syms
-    struct:
-    - name: __t__
-      dtype: int64
-    - name: shape
-      list: int64
-    - name: dtype
-      dtype: string
-    - name: data
-      dtype: binary
-    - name: q
-      dtype: string
-    - name: scale
-      dtype: float64
-    - name: pack
-      dtype: string
-    - name: z
-      dtype: string
-    - name: nbytes
-      dtype: int64
-  - name: obj_kpts3d_syms
-    struct:
-    - name: __t__
-      dtype: int64
-    - name: shape
-      list: int64
-    - name: dtype
-      dtype: string
-    - name: data
-      dtype: binary
-    - name: q
-      dtype: string
-    - name: scale
-      dtype: float64
-    - name: pack
-      dtype: string
-    - name: z
-      dtype: string
-    - name: nbytes
-      dtype: int64
-  - name: obj_axis6d_sym
-    struct:
-    - name: __t__
-      dtype: int64
-    - name: shape
-      list: int64
-    - name: dtype
-      dtype: string
-    - name: data
-      dtype: binary
-    - name: q
-      dtype: string
-    - name: scale
-      dtype: float64
-    - name: pack
-      dtype: string
-    - name: z
-      dtype: string
-    - name: nbytes
-      dtype: int64
-  - name: obj_verts_part_id
-    struct:
-    - name: __t__
-      dtype: int64
-    - name: shape
-      list: int64
-    - name: dtype
-      dtype: string
-    - name: data
-      dtype: binary
-    - name: q
-      dtype: string
-    - name: scale
-      dtype: float64
-    - name: pack
-      dtype: string
-    - name: z
-      dtype: string
-    - name: nbytes
-      dtype: int64
-  - name: category
-    dtype: string
-  - name: category_id
-    dtype: int64
-  - name: attributes
-    dtype: 'null'
-  - name: frame_id
-    dtype: string
-  - name: cam_intr4x4
-    struct:
-    - name: __t__
-      dtype: int64
-    - name: shape
-      list: int64
-    - name: dtype
-      dtype: string
-    - name: data
-      dtype: binary
-    - name: q
-      dtype: string
-    - name: scale
-      dtype: float64
-    - name: pack
-      dtype: string
-    - name: z
-      dtype: string
-    - name: nbytes
-      dtype: int64
-  - name: rgb
-    struct:
-    - name: __t__
-      dtype: int64
-    - name: shape
-      list: int64
-    - name: dtype
-      dtype: string
-    - name: data
-      dtype: binary
-    - name: q
-      dtype: string
-    - name: scale
-      dtype: float64
-    - name: pack
-      dtype: string
-    - name: z
-      dtype: string
-    - name: nbytes
-      dtype: int64
-  - name: depth
-    struct:
-    - name: __t__
-      dtype: int64
-    - name: shape
-      list: int64
-    - name: dtype
-      dtype: string
-    - name: data
-      dtype: binary
-    - name: q
-      dtype: string
-    - name: scale
-      dtype: float64
-    - name: pack
-      dtype: string
-    - name: z
-      dtype: string
-    - name: nbytes
-      dtype: int64
-  - name: depth_mask
-    struct:
-    - name: __t__
-      dtype: int64
-    - name: shape
-      list: int64
-    - name: dtype
-      dtype: string
-    - name: data
-      dtype: binary
-    - name: q
-      dtype: string
-    - name: scale
-      dtype: float64
-    - name: pack
-      dtype: string
-    - name: z
-      dtype: string
-    - name: nbytes
-      dtype: int64
-  - name: mask
-    struct:
-    - name: __t__
-      dtype: int64
-    - name: shape
-      list: int64
-    - name: dtype
-      dtype: string
-    - name: data
-      dtype: binary
-    - name: q
-      dtype: string
-    - name: scale
-      dtype: float64
-    - name: pack
-      dtype: string
-    - name: z
-      dtype: string
-    - name: nbytes
-      dtype: int64
-  - name: normal
-    struct:
-    - name: __t__
-      dtype: int64
-    - name: shape
-      list: int64
-    - name: dtype
-      dtype: string
-    - name: data
-      dtype: binary
-    - name: q
-      dtype: string
-    - name: scale
-      dtype: float64
-    - name: pack
-      dtype: string
-    - name: z
-      dtype: string
-    - name: nbytes
-      dtype: int64
-  - name: feat
-    struct:
-    - name: __t__
-      dtype: int64
-    - name: shape
-      list: int64
-    - name: dtype
-      dtype: string
-    - name: data
-      dtype: binary
-    - name: q
-      dtype: string
-    - name: scale
-      dtype: float64
-    - name: pack
-      dtype: string
-    - name: z
-      dtype: string
-    - name: nbytes
-      dtype: int64
-  - name: featmap
-    struct:
-    - name: __t__
-      dtype: int64
-    - name: shape
-      list: int64
-    - name: dtype
-      dtype: string
-    - name: data
-      dtype: binary
-    - name: q
-      dtype: string
-    - name: scale
-      dtype: float64
-    - name: pack
-      dtype: string
-    - name: z
-      dtype: string
-    - name: nbytes
-      dtype: int64
-  - name: featmap_lvls
-    struct:
-    - name: __l__
-      list:
-      - name: __t__
-        dtype: int64
-      - name: shape
-        list: int64
-      - name: dtype
-        dtype: string
-      - name: data
-        dtype: binary
-      - name: q
-        dtype: string
-      - name: scale
-        dtype: float64
-      - name: pack
-        dtype: string
-      - name: z
-        dtype: string
-      - name: nbytes
-        dtype: int64
-  - name: frame_object_id
-    dtype: string
-  - name: cam_bbox2d
-    struct:
-    - name: __t__
-      dtype: int64
-    - name: shape
-      list: int64
-    - name: dtype
-      dtype: string
-    - name: data
-      dtype: binary
-    - name: q
-      dtype: string
-    - name: scale
-      dtype: float64
-    - name: pack
-      dtype: string
-    - name: z
-      dtype: string
-    - name: nbytes
-      dtype: int64
-  - name: cam_bbox3d
-    struct:
-    - name: __t__
-      dtype: int64
-    - name: shape
-      list: int64
-    - name: dtype
-      dtype: string
-    - name: data
-      dtype: binary
-    - name: q
-      dtype: string
-    - name: scale
-      dtype: float64
-    - name: pack
-      dtype: string
-    - name: z
-      dtype: string
-    - name: nbytes
-      dtype: int64
-  - name: fo_mask
-    struct:
-    - name: __t__
-      dtype: int64
-    - name: shape
-      list: int64
-    - name: dtype
-      dtype: string
-    - name: data
-      dtype: binary
-    - name: q
-      dtype: string
-    - name: scale
-      dtype: float64
-    - name: pack
-      dtype: string
-    - name: z
-      dtype: string
-    - name: nbytes
-      dtype: int64
-  - name: fo_mask_dt
-    struct:
-    - name: __t__
-      dtype: int64
-    - name: shape
-      list: int64
-    - name: dtype
-      dtype: string
-    - name: data
-      dtype: binary
-    - name: q
-      dtype: string
-    - name: scale
-      dtype: float64
-    - name: pack
-      dtype: string
-    - name: z
-      dtype: string
-    - name: nbytes
-      dtype: int64
-  - name: fo_mask_amodal
-    struct:
-    - name: __t__
-      dtype: int64
-    - name: shape
-      list: int64
-    - name: dtype
-      dtype: string
-    - name: data
-      dtype: binary
-    - name: q
-      dtype: string
-    - name: scale
-      dtype: float64
-    - name: pack
-      dtype: string
-    - name: z
-      dtype: string
-    - name: nbytes
-      dtype: int64
-  - name: fo_mask_amodal_dt
-    struct:
-    - name: __t__
-      dtype: int64
-    - name: shape
-      list: int64
-    - name: dtype
-      dtype: string
-    - name: data
-      dtype: binary
-    - name: q
-      dtype: string
-    - name: scale
-      dtype: float64
-    - name: pack
-      dtype: string
-    - name: z
-      dtype: string
-    - name: nbytes
-      dtype: int64
-  - name: obj_kpts2d_mask
-    struct:
-    - name: __t__
-      dtype: int64
-    - name: shape
-      list: int64
-    - name: dtype
-      dtype: string
-    - name: data
-      dtype: binary
-    - name: q
-      dtype: string
-    - name: scale
-      dtype: float64
-    - name: pack
-      dtype: string
-    - name: z
-      dtype: string
-    - name: nbytes
-      dtype: int64
-  - name: cam_tform4x4_obj
-    struct:
-    - name: __t__
-      dtype: int64
-    - name: shape
-      list: int64
-    - name: dtype
-      dtype: string
-    - name: data
-      dtype: binary
-    - name: q
-      dtype: string
-    - name: scale
-      dtype: float64
-    - name: pack
-      dtype: string
-    - name: z
-      dtype: string
-    - name: nbytes
-      dtype: int64
-  - name: cam_tform4x4_obj_ncds
-    struct:
-    - name: __t__
-      dtype: int64
-    - name: shape
-      list: int64
-    - name: dtype
-      dtype: string
-    - name: data
-      dtype: binary
-    - name: q
-      dtype: string
-    - name: scale
-      dtype: float64
-    - name: pack
-      dtype: string
-    - name: z
-      dtype: string
-    - name: nbytes
-      dtype: int64
-  splits:
-  - name: test
-    num_bytes: 8586502725
-    num_examples: 58382
-  download_size: 8514159824
-  dataset_size: 8586502725
-- config_name: frames_meshes
-  features:
-  - name: object_id
-    dtype: string
-  - name: mesh
-    struct:
-    - name: __dc__
-      dtype: string
-    - name: fields
-      struct:
-      - name: verts
-        struct:
-        - name: __t__
-          dtype: int64
-        - name: shape
-          list: int64
-        - name: dtype
-          dtype: string
-        - name: data
-          dtype: binary
-        - name: q
-          dtype: string
-        - name: scale
-          dtype: float64
-        - name: pack
-          dtype: string
-        - name: z
-          dtype: string
-        - name: nbytes
-          dtype: int64
-      - name: faces
-        struct:
-        - name: __t__
-          dtype: int64
-        - name: shape
-          list: int64
-        - name: dtype
-          dtype: string
-        - name: data
-          dtype: binary
-        - name: q
-          dtype: string
-        - name: scale
-          dtype: float64
-        - name: pack
-          dtype: string
-        - name: z
-          dtype: string
-        - name: nbytes
-          dtype: int64
-      - name: vert_colors
-        dtype: 'null'
-      - name: verts_uvs
-        dtype: 'null'
-      - name: faces_uvs
-        dtype: 'null'
-      - name: texture
-        dtype: 'null'
-      - name: vert_feats
-        dtype: 'null'
-  splits:
-  - name: test
-    num_bytes: 34284941
-    num_examples: 3652
-  download_size: 34241194
-  dataset_size: 34284941
+license: cc-by-4.0
+pretty_name: Every9D
+tags:
+  - 6d-pose-estimation
+  - 9d-pose-estimation
+  - category-level
+  - rgb-d
+  - uco3d
+size_categories:
+  - 1M<n<10M
 configs:
-- config_name: frames
-  data_files:
-  - split: test
-    path: frames/test-*
-- config_name: frames_meshes
-  data_files:
-  - split: test
-    path: frames_meshes/test-*
+  - config_name: frames
+    data_files:
+      - {split: test, path: "frames/test-*.parquet"}
+  - config_name: frames_meshes
+    data_files:
+      - {split: test, path: "frames_meshes/test-*.parquet"}
+  - config_name: tforms
+    data_files:
+      - {split: train, path: "tforms/train.parquet"}
+      - {split: test, path: "tforms/test.parquet"}
 ---
+
+# Every9D
+
+Every9D gives the videos of [uCO3D](https://github.com/facebookresearch/uco3d)
+category-level 9-D object poses: rotation, translation and 3-D size, expressed in
+one canonical frame per category.
+
+| Split | Sequences | Frames in `frames` | Categories |
+|-------|-----------|--------------------|------------|
+| `train` | 110,543 | 1,768,255 | 894 |
+| `test` | 3,651 | 58,382 | 898 |
+| **Total** | **114,194** | **1,826,637** | **959** |
+
+The `tforms` config holds one row per sequence, so 114,194 rows in total.
+
+| Config | What it holds | Size | Needs uCO3D? |
+|--------|---------------|------|--------------|
+| `tforms` | One rigid transform per sequence, plus size and symmetry. Gives a pose for **every frame** of a uCO3D video | ~10 MB | yes, for images and cameras |
+| `frames` | Ready-to-train RGB-D crops at 256 × 256, up to 16 frames per sequence | ~254 GB | no |
+| `frames_meshes` | The `alpha500` mesh of each sequence, used for the amodal masks | ~1 GB | no |
+
+Train and test are disjoint, and no object appears in both. The 65 categories with
+a single sequence appear in test only, so they have no train object.
+
+## Option A: use the crops
+
+No uCO3D download is needed. Stream the data, as the full train split is about 250 GB:
+
+```python
+from datasets import load_dataset
+import numpy as np, pyarrow as pa
+
+def decode(t):
+    """Decode one stored tensor into a numpy array."""
+    raw = t["data"]
+    if t["z"] == "zstd":
+        raw = pa.Codec("zstd").decompress(raw, decompressed_size=t["nbytes"], asbytes=True)
+    if t["pack"] == "bits":
+        n = int(np.prod(t["shape"]))
+        return np.unpackbits(np.frombuffer(raw, np.uint8), count=n).astype(bool).reshape(t["shape"])
+    if t["q"]:
+        a = np.frombuffer(raw, np.uint8 if t["q"] == "u8" else np.uint16).astype(np.float32)
+        return (a / np.float32(t["scale"])).reshape(t["shape"])
+    return np.frombuffer(raw, np.dtype(t["dtype"])).reshape(t["shape"])
+
+ds = load_dataset("GenIntelLab/Every9D", "frames", split="test", streaming=True)
+row = next(iter(ds))
+rgb  = decode(row["rgb"])               # (3, 256, 256) float32 in [0, 1]
+pose = decode(row["cam_tform4x4_obj"])  # (4, 4)
+```
+
+Tensors are stored compressed, so the Hub viewer shows them as binary. Always go
+through `decode`. Each row has these fields:
+
+| Field | Shape | Meaning |
+|-------|-------|---------|
+| `frame_id` | str | `<category>/<sequence>/<frame_number>` |
+| `object_id` | str | `<category>/<sequence>` |
+| `category`, `category_id` | str, int | Every9D category |
+| `rgb` | (3, 256, 256) | float32 in [0, 1] |
+| `depth`, `depth_mask` | (256, 256) | depth in the sequence's units (see below), valid pixels |
+| `fo_mask` | (256, 256) | visible object mask |
+| `fo_mask_amodal`, `fo_mask_amodal_dt` | (256, 256) | `alpha500` mesh rendered under the pose, and its distance transform |
+| `cam_intr4x4` | (4, 4) | intrinsics **of the crop** |
+| `cam_tform4x4_obj` | (4, 4) | object → camera, rigid |
+| `obj_ncds0c_tform4x4_obj` | (4, 4) | normalised object coordinates → object space |
+| `cam_tform4x4_obj_ncds` | (4, 4) | `cam_tform4x4_obj @ obj_ncds0c_tform4x4_obj` |
+| `obj_size3d` | (3,) | box side lengths along X, Y, Z |
+| `obj_syms` | (3,) | per-axis symmetry code |
+| `cam_bbox2d`, `cam_bbox3d` | (4,), (8, 3) | object boxes in the crop and in camera space |
+
+## Option B: poses for every frame of a uCO3D video
+
+Download uCO3D's `metadata.sqlite`, and any videos you need, with
+[its download script](https://github.com/facebookresearch/uco3d). Then combine its
+cameras with the `tforms` table:
+
+```python
+import sqlite3, struct
+import numpy as np
+from datasets import load_dataset
+
+tforms = {}
+for split in ("train", "test"):
+    for r in load_dataset("GenIntelLab/Every9D", "tforms", split=split):
+        tforms[r["sequence_name"]] = r
+
+# uCO3D (PyTorch3D) camera -> Every9D camera (OpenGL: +X right, +Y up, -Z forward)
+CAM = np.diag([-1.0, 1.0, -1.0, 1.0])
+
+def cam_tform4x4_obj(R_blob, T_blob, world_tform4x4_obj):
+    """Object -> camera, from uCO3D's _viewpoint_R and _viewpoint_T."""
+    cam_tform4x4_world = np.eye(4)
+    cam_tform4x4_world[:3, :3] = np.array(struct.unpack("<9f", R_blob)).reshape(3, 3).T
+    cam_tform4x4_world[:3, 3] = struct.unpack("<3f", T_blob)
+    return CAM @ cam_tform4x4_world @ world_tform4x4_obj
+
+def cam_intr3x3(f_blob, p_blob, size_blob):
+    """Pixel intrinsics of the full frame, for intrinsics format ndc_isotropic."""
+    (fx, fy), (px, py) = struct.unpack("<2f", f_blob), struct.unpack("<2f", p_blob)
+    h, w = struct.unpack("<2I", size_blob)
+    s = min(h, w) / 2.0
+    return np.array([[fx * s, 0, -px * s + w / 2], [0, fy * s, -py * s + h / 2], [0, 0, 1]])
+
+db = sqlite3.connect("metadata.sqlite")
+sequence = "109-89486-96842"
+t = tforms[sequence]
+world_tform4x4_obj = np.array(t["world_tform4x4_obj"]).reshape(4, 4)
+
+poses = {}
+for frame, R, T, f, p, size in db.execute(
+    "SELECT frame_number, _viewpoint_R, _viewpoint_T, _viewpoint_focal_length,"
+    " _viewpoint_principal_point, _image_size FROM frame_annots"
+    " WHERE sequence_name = ? ORDER BY frame_number", (sequence,)):
+    poses[frame] = (cam_tform4x4_obj(R, T, world_tform4x4_obj), cam_intr3x3(f, p, size))
+```
+
+### From uCO3D's camera pose to Every9D's
+
+`cam_tform4x4_obj` above takes three steps from uCO3D's camera to the Every9D pose:
+
+```text
+cam_tform4x4_obj = CAM @ cam_tform4x4_world @ world_tform4x4_obj
+```
+
+1. **Build uCO3D's camera matrix, `cam_tform4x4_world`.** `_viewpoint_R` and
+   `_viewpoint_T` use PyTorch3D's row-vector convention, `x_cam = x_world R + T`. As
+   a matrix for column vectors, the rotation block is therefore `R.T` and the
+   translation is `T`. The result maps the sequence's SfM frame into uCO3D's camera,
+   with +X left, +Y up and +Z forward.
+2. **Change the object frame with `world_tform4x4_obj`.** Multiplying on the right
+   replaces the arbitrary SfM frame with the Every9D object frame. This matrix
+   already includes the category's canonical rotation and axis order. It is rigid, so
+   the result stays in the sequence's SfM units.
+3. **Change the camera to OpenGL with `CAM = diag(-1, 1, -1, 1)`.** Multiplying on
+   the left negates camera X and Z, which gives +X right, +Y up and -Z forward. For
+   OpenCV instead (+X right, +Y down, +Z forward), use `diag(-1, -1, 1, 1)`.
+
+For frames that are in the `frames` config, the OpenGL result equals the stored
+`cam_tform4x4_obj`. The intrinsics do not: `cam_intr3x3` gives those of the full
+frame, while the stored `cam_intr4x4` belongs to the 256 × 256 crop.
+
+### Projecting points
+
+To project an object point `x` in object space, apply `cam_tform4x4_obj` to get
+`(X, Y, Z)` with `Z < 0`, then `u = cx + fx * X / -Z` and `v = cy - fy * Y / -Z`.
+
+Each row of `tforms` has these fields:
+
+| Field | Meaning |
+|-------|---------|
+| `sequence_name` | **Join key.** Unique in uCO3D, and the same name as in `metadata.sqlite` |
+| `uco3d_category` | Category as uCO3D spells it (`pug-dog`) |
+| `category` | Category as Every9D spells it (`pug_dog`), as in `frame_id` |
+| `split` | `train` or `test` |
+| `world_tform4x4_obj` | 16 floats, row-major: rigid, Every9D object frame → uCO3D sequence (SfM) frame |
+| `obj_ncds0c_tform4x4_obj` | 16 floats, row-major: normalised object coordinates → object frame |
+| `obj_size3d` | Box side lengths along X, Y, Z |
+| `obj_syms` | Per-axis symmetry code |
+
+Join on `sequence_name`, not on the category: the two spellings differ for a few
+categories.
+
+## Conventions
+
+- **Camera:** OpenGL, with +X right, +Y up and -Z forward. Objects in front of the camera have negative camera Z.
+- **Object frame:** X = right, Y = top, Z = back of the category's canonical orientation.
+- **Object origin:** the origin of the object frame is **not** the object's centre. For a centred pose use `cam_tform4x4_obj @ obj_ncds0c_tform4x4_obj`, which maps a normalised object, centred with its longest side spanning [-1, 1], into the camera.
+- **Units:** translations, depth and `obj_size3d` are in the units of each sequence's SfM reconstruction, **not metres**. An aerosol can may be 1.4 units tall, so do not compare absolute sizes across sequences.
+
+## Limitations
+
+- Poses inherit uCO3D's cameras. Canonical orientations were reviewed per category, but individual sequences can still be wrong.
+- `alpha500` meshes are alpha-shape reconstructions from uCO3D's segmented point clouds, not artist meshes. Thin parts can be missing, so the amodal masks are approximate.
+- `frames` holds up to 16 frames per sequence, and at least 9. Use Option B to reach the rest.
+
+## License and citation
+
+Released under [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/). The images,
+depth and cameras derive from uCO3D, also CC BY 4.0, so please credit both.
+
+```bibtex
+% TODO: Every9D citation
+% TODO: uCO3D citation, arXiv:2501.07574
+```