| --- |
| pretty_name: Lance Captured Trajectory Dataset |
| language: |
| - en |
| tags: |
| - lance |
| - trajectory |
| - mano |
| - robotics |
| - motion-capture |
| task_categories: |
| - robotics |
| - time-series-forecasting |
| --- |
| |
| # lance_dataset |
| |
| This repository stores Lance datasets. |
| |
| The current dataset is organized as `Dexcanvas.lance/`. It contains Lance data fragments, version manifests, and transaction metadata. |
| |
| ## Dataset Structure |
| |
| `Dexcanvas.lance` represents a captured trajectory dataset. Each row corresponds to one complete captured trajectory. The field definitions are based on `captured_data_schema.yaml`. |
| |
| Key conventions: |
| |
| - `trajectory_metadata.total_frames` defines the sequence length `T` |
| - All sequence fields must have the same `T` dimension |
| - All rotations are represented in axis-angle format |
| - All positions are measured in meters |
| |
| ## MANO Trajectory Fields |
| |
| MANO-related data is split into metadata fields and time-series fields. |
| |
| ### Metadata |
| |
| The following fields in `trajectory_metadata` describe the hand layout: |
|
|
| - `hand_names`: variable-length list of hand names |
| - `mano_hand_shapes`: MANO shape parameters for each hand |
|
|
| Index mapping: |
|
|
| - `hand_names[i]` corresponds to `hands[i]` |
| - `mano_hand_shapes[i]` corresponds to `hands[i]` |
|
|
| ### Time-Series Data |
|
|
| `hands[]` is a variable-length array. Each element represents one hand over the full trajectory. |
|
|
| - `mano_global_pos` `(T, 3)` |
| Global hand position in meters. |
| - `mano_global_rot_aa` `(T, 3)` |
| Global hand rotation in axis-angle format. |
| - `mano_hand_pose` `(T, 48)` |
| MANO hand pose parameters. |
| - 45 dimensions for 15 joint rotations |
| - 3 dimensions for the wrist |
| - `mano_joint_pos` `(T, 21, 3)` |
| 3D positions of 21 MANO hand joints. |
| - `urdf_dof` `(T, 26)` |
| URDF degree-of-freedom representation. |
| - 20 finger DOFs |
| - 6 wrist DOFs |
|
|
| In short: |
|
|
| - `mano_global_pos` and `mano_global_rot_aa` describe the global hand pose |
| - `mano_hand_pose` describes MANO finger and wrist pose parameters |
| - `mano_joint_pos` provides the derived 3D hand joint positions |
| - `urdf_dof` provides a robot/control-oriented representation |
|
|
| ## Object Fields |
|
|
| Object-related data is stored in `trajectory_metadata.object_names` and `objects[]`. |
|
|
| ### Metadata |
|
|
| - `object_names`: variable-length list of object names |
|
|
| Index mapping: |
|
|
| - `object_names[i]` corresponds to `objects[i]` |
|
|
| ### Time-Series Data |
|
|
| `objects[]` is a variable-length array. Each element represents one object over the full trajectory. |
|
|
| - `rot_aa` `(T, 3)` |
| Object rotation in axis-angle format. |
| - `pos` `(T, 3)` |
| Object position in meters. |
|
|
| Therefore, `objects[i]` stores the full pose trajectory of the `i`-th object across all `T` frames. |
|
|
| ## Other Common Fields |
|
|
| - `index.uuid`: unique trajectory identifier |
| - `index.seed_uuid`: same as `uuid` for captured data; source trajectory ID for generated data |
| - `index.file_uuid`: source `session_data_files.file_uuid` |
| - `index.capMachine`: capture machine identifier |
| - `index.operator`: operator who captured or generated the data |
| - `index.scene`: scene identifier |
| - `index.is_generated`: whether the row is generated data |
| - `timestamp`: per-frame timestamps |
| - `atomic_actions`: atomic action intervals, such as grasp or release |
|
|
| ## Directory Layout |
|
|
| - `Dexcanvas.lance/`: Lance dataset root |
| - `Dexcanvas.lance/data/`: physical Lance data fragments |
| - `Dexcanvas.lance/_versions/`: dataset version manifests |
| - `Dexcanvas.lance/_transactions/`: transaction records |
| - `Dexcanvas.lance/_latest.manifest`: latest dataset manifest |
| - `captured_data_schema.yaml`: YAML schema converted from the upstream JSONC schema |
|
|
| ## Notes |
|
|
| When adding new fields, keep them consistent with `captured_data_schema.yaml`, especially: |
|
|
| - The shared `T` dimension for sequence fields |
| - The index mapping between `hands[]` and `trajectory_metadata.hand_names` |
| - The index mapping between `objects[]` and `trajectory_metadata.object_names` |
| - Axis-angle rotation representation |
|
|
