README: embed dataset figures + statistics gallery

README.md

@@ -28,6 +28,25 @@ configs:
 
 Multimodal manipulation recordings from a bimanual setup with vision-based tactile sensors and motion capture.
 
+![Contact timeline](figures/contact_timeline_binary.png)
+
+> **30 episodes · 138.4 min total · 87.9 min (66%) of confirmed bimanual tactile contact · 3× RGB-D cameras + 2× GelSight + 3-body OptiTrack.**
+
+## At a glance
+
+| | |
+|---|---|
+| Tasks | `motherboard` (more coming) |
+| Episodes | 30 |
+| Total duration | **138.4 min** (median 4 min/episode, longest 19 min) |
+| Tactile contact | **87.9 min / 66% of frames** (4,136 contact events, median 0.73 s each) |
+| Cameras | 3× Intel RealSense D415 (color + depth, 480×640, 30 FPS) |
+| Tactile | 2× GelSight Mini (left / right, 480×640, ~25 FPS) |
+| Motion capture | OptiTrack VRPN, 3 rigid bodies, ~120 Hz |
+| License | CC-BY-4.0 |
+
+![Comparison table](figures/dataset_figures/F7_comparison_table.png)
+
 ## Recording setup
 
 | Stream | Hardware | Native shape | Rate |
@@ -41,7 +60,7 @@ All streams share a common monotonic timestamp axis recorded under `timestamps`.
 
 ## Tasks
 
-The dataset is organized **task-first** so new tasks can be added without renaming or recompute. Current tasks:
+The dataset is organized **task-first** so new tasks can be added without renaming or recompute.
 
 | Task | Description | Dates | Episodes |
 |---|---|---|---|
@@ -49,6 +68,54 @@ The dataset is organized **task-first** so new tasks can be added without renami
 
 `tasks.json` at the repo root is the source of truth for the task registry.
 
+## Episode previews
+
+Each `figures/episode_previews/motherboard/<date>/episode_NNN.gif` shows the first 2 minutes of that episode at 15× speed (≈8 s loop, 3-panel layout: overhead camera | tactile left | tactile right). Browse them in the [`figures/episode_previews`](figures/episode_previews) folder of this repo.
+
+## Statistics & analysis
+
+### Episode length
+
+![Episode length](figures/dataset_figures/F1_episode_length_histogram.png)
+
+Most episodes run 1–10 min; the median is **4 min** — roughly 8× longer than BridgeData V2's typical 30 s demo. The longest episode is 19 min.
+
+### Contact event durations
+
+![Contact event durations](figures/dataset_figures/F2_contact_event_duration_histogram.png)
+
+4,136 contact events total. The typical contact event lasts ≈ **0.7 s** (median), with a long tail out to 33 s — useful for grasp/contact-classification downstream tasks.
+
+### Where on the gel does contact land?
+
+![Contact heatmap](figures/dataset_figures/F3_contact_heatmap.png)
+
+Both sensors show contact concentrated in the central ~50% of the gel surface, dropping off toward the edges. The left gel has discrete bright spots from repeated contacts with specific features.
+
+### Tactile signal is real and varied (not flat noise)
+
+![Tactile montage](figures/dataset_figures/F4_tactile_pattern_montage.png)
+
+16 random contact frames sampled across the dataset — discrete pins, edges, smooth surfaces, multi-object contact.
+
+### Bimanual workspace
+
+![Pose trajectory](figures/dataset_figures/F5_pose_trajectory_3d.png)
+
+Multi-view projection of the longest episode (2026-05-11 / ep_017, 19 min). Left (blue) and right (orange) sensors operate over a ~30 × 40 × 30 cm workspace.
+
+### Tactile is independent of motion
+
+![Cross-modal correlation](figures/dataset_figures/F6_cross_modal_correlation.png)
+
+Sensor velocity vs tactile intensity is **essentially uncorrelated** (r ≈ +0.04 / −0.05). Tactile carries information that is **not** explained by pose+velocity — a direct argument for the value of including tactile in policy / world-model training.
+
+### Per-episode summary
+
+![Per-episode summary](figures/dataset_figures/F8_per_episode_summary.png)
+
+Detailed table also exported as CSV: [`figures/dataset_figures/F8_per_episode_summary.csv`](figures/dataset_figures/F8_per_episode_summary.csv).
+
 ## Repository layout
 
 ```
@@ -60,6 +127,11 @@ processed/
             ├─ episode_000.pt
             ├─ episode_000.contact.json
             └─ ...
+figures/
+├─ contact_timeline_binary.png         # contact vs no-contact, per episode
+├─ contact_timeline_lr.png             # left-only / right-only / both / neither
+├─ episode_previews/<task>/<date>/episode_*.gif   # per-episode GIF previews
+└─ dataset_figures/                    # F1–F8 statistics and analysis figures
 ```
 
 The `processed/mode1_v1/` view is a **task-specific slice** of the underlying raw recordings, not the full sensor suite. It was produced by `twm/preprocess.py` + `twm/contact_index.py` from a private raw HDF5 mirror.
@@ -138,7 +210,7 @@ print(meta["drift_left"], meta["drift_right"], meta["drift_warning"])
 ## Known caveats
 
 - **Missing / dropped episodes** on `motherboard/2026-05-11`:
-  - `episode_000` and `episode_002` — short test recordings (8.8s and 10.4s) with no tactile contact on either sensor; intentionally excluded.
+  - `episode_000` and `episode_002` — short test recordings (8.8 s and 10.4 s) with no tactile contact on either sensor; intentionally excluded.
   - `episode_001` — lost at recording time (HDF5 superblock never finalized when the writer was killed mid-write); intentionally absent.
   - The remaining episode IDs are non-contiguous as a result. Don't infer ordering from filename gaps.
 - **Lossy resize**: the 128×128 `view` and tactile fields are downsampled from native 480×640. Native resolution is **not** preserved in this release.