| # Trajectory deduplication (`dedup/`) |
|
|
| Near-duplicate removal over the 94,030-episode DROID LeRobot export |
| (94,006 episodes with valid kinematic signals were assessed; 24 episodes with |
| degenerate signals are kept by default). A duplicate is a **near-identical |
| re-recording of the same task**; different tasks — including paraphrases |
| resolved to different tasks, object swaps, or the same task done in a |
| different place — are treated as diversity and never merged. |
|
|
| ## Method |
|
|
| 1. **Merge task phrasings** — instructions are canonicalised (synonym folding |
| for verbs/objects, prepositions to `<p>`, articles dropped, order and |
| attributes preserved): 31,304 distinct instruction strings → 28,458 task |
| families. Episodes without an instruction (task_index 31051, 43,133 |
| episodes) are grouped by their labeled verb+object chain instead. |
| 2. **Trajectory signature** — keyframes = gripper open/close events + |
| end-effector deceleration points; the keyframe EE positions are |
| start-centred and arc-length-resampled to K=8 points → a 24-number |
| signature per episode (see `descriptors.npz`). |
| 3. **Duplicate rule** — same family AND mean per-point Euclidean distance |
| < **3 cm** AND identical gripper open/close pattern. Leader clustering: |
| every member is within 3 cm of its cluster leader, so transitive chains |
| cannot glue far-apart trajectories together. |
| 4. **Keep TWO per cluster** (`DEDUP_KEEP=2`) — the cluster **medoid** plus the |
| member **farthest from the medoid** (greedy max-min), retaining the |
| cluster's residual spread. Clusters of size 2 are kept whole. |
|
|
| ## Results (eps = 3 cm, keep = 2) |
|
|
| | metric | value | |
| |---|---| |
| | episodes assessed | 94,006 | |
| | episodes in multi-episode clusters | 8,656 (9.21%) | |
| | multi-episode clusters | 2,260 (largest: 539 frozen no-instruction episodes) | |
| | episodes kept (hard dedup) | **89,870** | |
| | episodes removed | 4,136 (4.40%) | |
|
|
| A stricter keep-one-per-cluster variant is archived as |
| `report_keep1.json` / `keep_list_keep1.txt` (87,610 kept / 6,396 removed). |
|
|
| ## Files |
|
|
| - `episode_weights.jsonl` — one line per episode: |
| `{episode_id, task_index, cluster_id, cluster_size, weight, representative}`. |
| `representative: true` ⇔ kept by hard dedup (2 per multi-cluster). Soft |
| weights: representatives 1.0, other members 1/cluster_size — use them to |
| reweigh instead of dropping. |
| - `seg_weights.jsonl` — `{seg_id, weight}` for all 588,151 annotated segments |
| (weight inherited from the episode; joins `annotations/segments.jsonl`). |
| - `keep_list.txt` — episode_id per line, the 89,870 kept episodes. |
| - `report.json` — the stats table above. |
| - `descriptors.npz` — `eids` (94,006), `tasks`, `descs` (94,006×8×3 float32, |
| metres, start-relative), `grips` (gripper pattern strings): everything |
| needed to re-run clustering at a different eps / keep policy. |
| - `keep_list_keep1.txt`, `report_keep1.json` — archived keep-1 variant. |
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|
