Add session/per-episode rest-gel reference (robust to all-contact episodes) + validation

data/motherboard/reference/manifest.json

@@ -0,0 +1,8 @@
+{
+  "2026-05-10/tactile_left": "2026-05-10/tactile_left.png",
+  "2026-05-10/tactile_right": "2026-05-10/tactile_right.png",
+  "2026-05-11/tactile_left": "2026-05-11/tactile_left.png",
+  "2026-05-11/tactile_right": "2026-05-11/tactile_right.png",
+  "2026-05-19/tactile_left": "2026-05-19/tactile_left.png",
+  "2026-05-19/tactile_right": "2026-05-19/tactile_right.png"
+}

data/motherboard/reference/validation.md

@@ -0,0 +1,74 @@
+# Rest-gel reference — corrected build + validation
+
+**Design (corrected after a drift check):** PRIMARY reference = per-episode fuzzy-mode (`fuzzy_mode_background`), drift-free and robust to partial contact. FALLBACK = per-session mode (`session_reference`, `<date>/tactile_*.png`) only for episodes that are ~100% contact (own mode contaminated).
+
+A single session reference is NOT a wholesale replacement: intra-day gel drift makes it differ from a given episode by a diffuse ~0.37 area with no object (see `drift_check.png`), so per-episode mode is preferred whenever the episode has clean frames.
+
+**Over 64 episode-sides:** need session fallback (no clean frame of own): **1** ['003 left']. Old p01 anchors that were a contact/marginal frame the per-episode MODE fixes: **0** [].
+
+| ep | date | side | frames | clean(vs own mode) | clean% | old_p01_area | flag |
+|---|---|---|---|---|---|---|---|
+| 003 | 2026-05-19 | left | 121 | 0 | 0.0 | 0.105 | NEEDS_SESSION_FALLBACK |
+| 017 | 2026-05-11 | left | 14511 | 636 | 4.4 | 0.009 |  |
+| 017 | 2026-05-11 | right | 14511 | 2441 | 16.8 | 0.001 |  |
+| 001 | 2026-05-19 | left | 740 | 149 | 20.1 | 0.002 |  |
+| 000 | 2026-05-19 | left | 1434 | 289 | 20.2 | 0.001 |  |
+| 004 | 2026-05-10 | right | 2406 | 591 | 24.6 | 0.0 |  |
+| 004 | 2026-05-19 | left | 209 | 52 | 24.9 | 0.005 |  |
+| 000 | 2026-05-19 | right | 1434 | 358 | 25.0 | 0.0 |  |
+| 006 | 2026-05-10 | right | 3925 | 1133 | 28.9 | 0.0 |  |
+| 002 | 2026-05-19 | left | 1710 | 568 | 33.2 | 0.0 |  |
+| 002 | 2026-05-19 | right | 1710 | 575 | 33.6 | 0.0 |  |
+| 011 | 2026-05-10 | right | 2201 | 743 | 33.8 | 0.0 |  |
+| 004 | 2026-05-10 | left | 2406 | 908 | 37.7 | 0.0 |  |
+| 010 | 2026-05-10 | left | 1035 | 403 | 38.9 | 0.001 |  |
+| 001 | 2026-05-19 | right | 740 | 295 | 39.9 | 0.0 |  |
+| 011 | 2026-05-10 | left | 2201 | 915 | 41.6 | 0.001 |  |
+| 008 | 2026-05-11 | right | 13705 | 5793 | 42.3 | 0.0 |  |
+| 009 | 2026-05-11 | right | 4366 | 1850 | 42.4 | 0.0 |  |
+| 004 | 2026-05-19 | right | 209 | 90 | 43.1 | 0.001 |  |
+| 014 | 2026-05-11 | right | 2416 | 1044 | 43.2 | 0.0 |  |
+| 006 | 2026-05-10 | left | 3925 | 1705 | 43.4 | 0.0 |  |
+| 009 | 2026-05-10 | right | 1823 | 807 | 44.3 | 0.0 |  |
+| 005 | 2026-05-10 | left | 763 | 342 | 44.8 | 0.001 |  |
+| 012 | 2026-05-11 | right | 14828 | 7426 | 50.1 | 0.0 |  |
+| 003 | 2026-05-10 | left | 9262 | 4653 | 50.2 | 0.0 |  |
+| 000 | 2026-05-10 | left | 6890 | 3534 | 51.3 | 0.0 |  |
+| 003 | 2026-05-19 | right | 121 | 65 | 53.7 | 0.0 |  |
+| 003 | 2026-05-10 | right | 9262 | 4979 | 53.8 | 0.0 |  |
+| 007 | 2026-05-10 | right | 1927 | 1039 | 53.9 | 0.0 |  |
+| 005 | 2026-05-11 | left | 14498 | 8123 | 56.0 | 0.001 |  |
+| 010 | 2026-05-10 | right | 1035 | 583 | 56.3 | 0.0 |  |
+| 013 | 2026-05-11 | right | 12724 | 7176 | 56.4 | 0.0 |  |
+| 007 | 2026-05-11 | right | 6908 | 3903 | 56.5 | 0.002 |  |
+| 007 | 2026-05-10 | left | 1927 | 1092 | 56.7 | 0.0 |  |
+| 016 | 2026-05-11 | left | 11896 | 6756 | 56.8 | 0.0 |  |
+| 015 | 2026-05-11 | right | 5959 | 3433 | 57.6 | 0.0 |  |
+| 001 | 2026-05-10 | left | 7621 | 4405 | 57.8 | 0.0 |  |
+| 008 | 2026-05-10 | right | 1305 | 760 | 58.2 | 0.0 |  |
+| 014 | 2026-05-11 | left | 2416 | 1413 | 58.5 | 0.0 |  |
+| 008 | 2026-05-10 | left | 1305 | 769 | 58.9 | 0.0 |  |
+| 010 | 2026-05-11 | right | 6828 | 4117 | 60.3 | 0.0 |  |
+| 012 | 2026-05-11 | left | 14828 | 9042 | 61.0 | 0.001 |  |
+| 016 | 2026-05-11 | right | 11896 | 7268 | 61.1 | 0.0 |  |
+| 011 | 2026-05-11 | right | 7299 | 4518 | 61.9 | 0.0 |  |
+| 009 | 2026-05-11 | left | 4366 | 2718 | 62.3 | 0.001 |  |
+| 005 | 2026-05-10 | right | 763 | 477 | 62.5 | 0.0 |  |
+| 002 | 2026-05-10 | left | 10475 | 6606 | 63.1 | 0.0 |  |
+| 006 | 2026-05-11 | left | 11990 | 7565 | 63.1 | 0.002 |  |
+| 009 | 2026-05-10 | left | 1823 | 1154 | 63.3 | 0.001 |  |
+| 006 | 2026-05-11 | right | 11990 | 7654 | 63.8 | 0.0 |  |
+| 008 | 2026-05-11 | left | 13705 | 8769 | 64.0 | 0.001 |  |
+| 015 | 2026-05-11 | left | 5959 | 3881 | 65.1 | 0.0 |  |
+| 003 | 2026-05-11 | left | 10032 | 6550 | 65.3 | 0.001 |  |
+| 005 | 2026-05-11 | right | 14498 | 9523 | 65.7 | 0.001 |  |
+| 010 | 2026-05-11 | left | 6828 | 4491 | 65.8 | 0.0 |  |
+| 007 | 2026-05-11 | left | 6908 | 4624 | 66.9 | 0.0 |  |
+| 004 | 2026-05-11 | left | 2638 | 1786 | 67.7 | 0.002 |  |
+| 000 | 2026-05-10 | right | 6890 | 4762 | 69.1 | 0.0 |  |
+| 011 | 2026-05-11 | left | 7299 | 5061 | 69.3 | 0.0 |  |
+| 004 | 2026-05-11 | right | 2638 | 1844 | 69.9 | 0.0 |  |
+| 002 | 2026-05-10 | right | 10475 | 7455 | 71.2 | 0.0 |  |
+| 003 | 2026-05-11 | right | 10032 | 7148 | 71.3 | 0.0 |  |
+| 013 | 2026-05-11 | left | 12724 | 9224 | 72.5 | 0.001 |  |
+| 001 | 2026-05-10 | right | 7621 | 5799 | 76.1 | 0.0 |  |

toolbox/__init__.py

@@ -9,7 +9,7 @@ React dataset (GelSight Mini, markerless, 640×480). MIT licensed.
     )
 """
 from .io import load_video, load_meta, episode_paths
-from .reference import get_reference, difference, l2_diff
+from .reference import get_reference, difference, l2_diff, fuzzy_mode_background, session_reference
 from .contact import contact_mask, contact_metrics, contact_centroid, TAU
 from .actions import next_state_action, delta_pose_action, integrate_delta
 from .viz import diff_heatmap, contact_overlay, reference_compare, depth_view, height_to_pointcloud
@@ -17,7 +17,7 @@ from .calibration import load_calibration, project_gel_to_pixel
 
 __all__ = [
     "load_video", "load_meta", "episode_paths",
-    "get_reference", "difference", "l2_diff",
+    "get_reference", "difference", "l2_diff", "fuzzy_mode_background", "session_reference",
     "contact_mask", "contact_metrics", "contact_centroid", "TAU",
     "next_state_action", "delta_pose_action", "integrate_delta",
     "diff_heatmap", "contact_overlay", "reference_compare", "depth_view", "height_to_pointcloud",

toolbox/build_session_references.py

@@ -0,0 +1,70 @@
+"""Build one rest-gel reference per (date, sensor) for the React dataset.
+
+Each episode is a cut from a continuous per-day recording, so all episodes of a
+date share one gel/lighting. This pools every episode's tactile frames for a
+date and takes the per-pixel fuzzy mode (the resting gel) -- robust even when an
+individual episode is in contact its whole length. Writes:
+
+    data/<task>/reference/<date>/tactile_{left,right}.png
+    data/<task>/reference/manifest.json
+
+Then use it instead of a per-episode reference:
+
+    ref = imageio.imread(f"data/{task}/reference/{date}/tactile_{side}.png")
+    diff = difference(frame, ref)                    # toolbox.reference
+
+Usage:
+    python -m toolbox.build_session_references --root data/motherboard
+"""
+from __future__ import annotations
+import argparse, json
+from collections import defaultdict
+from pathlib import Path
+
+import numpy as np
+import imageio.v2 as imageio
+
+from .io import load_video, episode_paths
+from .reference import session_reference
+
+
+def main():
+    ap = argparse.ArgumentParser()
+    ap.add_argument("--root", required=True, help="task root, e.g. data/motherboard")
+    ap.add_argument("--episodes_jsonl", default=None,
+                    help="defaults to <root>/episodes.jsonl")
+    ap.add_argument("--stride", type=int, default=3, help="frame subsample for speed")
+    ap.add_argument("--max_frames", type=int, default=4000)
+    args = ap.parse_args()
+    root = Path(args.root)
+    jl = Path(args.episodes_jsonl or (root / "episodes.jsonl"))
+    eps = [json.loads(l) for l in jl.read_text().splitlines() if l.strip()]
+
+    by_date = defaultdict(list)
+    for e in eps:
+        by_date[e["date"]].append(e["episode"])
+
+    manifest = {}
+    for date, ep_keys in sorted(by_date.items()):
+        for side in ("left", "right"):
+            frames = []
+            for ek in sorted(ep_keys):
+                p = episode_paths(root, ek)["tactile_" + side]
+                if not Path(p).is_file():
+                    continue
+                v = load_video(p)                       # (T,H,W,3)
+                frames.append(v[:: args.stride])
+            if not frames:
+                continue
+            ref = session_reference(frames, max_frames=args.max_frames)
+            out = root / "reference" / date / f"tactile_{side}.png"
+            out.parent.mkdir(parents=True, exist_ok=True)
+            imageio.imwrite(out, ref)
+            manifest[f"{date}/tactile_{side}"] = str(out.relative_to(root))
+            print(f"[ref] {date} {side}: pooled {len(frames)} episodes -> {out}")
+    (root / "reference" / "manifest.json").write_text(json.dumps(manifest, indent=2))
+    print(f"[done] {len(manifest)} references")
+
+
+if __name__ == "__main__":
+    main()

toolbox/reference.py

@@ -73,3 +73,76 @@ def l2_diff(frame, reference):
     d[h,w] = ||frame[h,w,:] - ref[h,w,:]||_2.
     """
     return np.sqrt(((frame.astype(np.float32) - reference.astype(np.float32)) ** 2).sum(axis=2))
+
+
+# ---------------------------------------------------------------------------
+# Robust rest-gel reference: per-episode fuzzy mode (+ session fallback)
+# ---------------------------------------------------------------------------
+#
+# get_reference(mode="p01") picks the quietest *frame* in an episode. Failure
+# modes (audit over motherboard, 64 episode-sides): it can pick a marginal /
+# contact frame when a clean frame is rare, and if the gel is in contact the
+# episode's ENTIRE length (ep003 left: 121 frames, all contact) there is no
+# clean frame at all -> the "reference" is a contact frame and the difference
+# image inverts.
+#
+# PRIMARY fix -- fuzzy_mode_background(episode_frames): the per-pixel temporal
+# fuzzy MODE is the resting gel even when a pixel is in contact part of the time
+# (robust past the median's 50%-occupancy limit). It is drift-free (this
+# episode's own gel state) and returns a clean reference whenever the gel is at
+# rest for a reasonable fraction of the clip.
+#
+# FALLBACK -- session_reference(all_episodes_of_a_day): for a ~100%-contact clip
+# even its own mode is contaminated. Each React episode is a cut from one
+# continuous per-day recording (episodes.jsonl `date`); pooling the day recovers
+# the rest gel because any pixel is untouched most of the day. Caveat: the gel's
+# fine texture/illumination can DRIFT within a day, so a single session
+# reference differs from a given episode by a diffuse global amount (verified:
+# |episode_clean_frame - session_ref| ~ 7/255 mean, area ~0.37, NO object). Use
+# the session reference ONLY when the episode has no clean frame of its own.
+
+
+def fuzzy_mode_background(frames, bin_w: int = 8, max_frames: int = 4000):
+    """Per-pixel temporal fuzzy-mode background (the resting gel).
+
+    frames: (T, H, W, 3) uint8. Returns (H, W, 3) uint8. The densest value-bin
+    (width bin_w ~= +-bin_w/2 tolerance) per pixel-channel, refined by the in-bin
+    mean. Robust where a pixel is in contact part of the time (unlike the
+    temporal median, which fails past 50% contact occupancy). The mode is
+    estimated on up to max_frames evenly-subsampled frames (the rest gel is
+    near-static). This is the PREFERRED per-episode reference.
+    """
+    import numpy as np
+    arr = np.asarray(frames)
+    T, H, W, C = arr.shape
+    if T > max_frames:
+        arr = arr[np.linspace(0, T - 1, max_frames).astype(np.int64)]
+    nb = 256 // bin_w
+    q = (arr.astype(np.int16) // bin_w).clip(max=nb - 1)
+    counts = np.stack([(q == b).sum(0) for b in range(nb)])
+    mode_bin = counts.argmax(0)
+    in_bin = (q == mode_bin[None]).astype(np.float32)
+    ref = (arr.astype(np.float32) * in_bin).sum(0) / np.clip(in_bin.sum(0), 1, None)
+    return ref.round().astype(np.uint8)
+
+
+def session_reference(episode_frames, bin_w: int = 8, max_frames: int = 4000):
+    """FALLBACK rest-gel reference for a whole session (list of episodes' frames).
+
+    episode_frames: a single (T,H,W,3) array or a list of them (all episodes of
+    one date, one sensor). Returns (H, W, 3) uint8. Use only for episodes with no
+    clean frame of their own; prefer fuzzy_mode_background otherwise (a session
+    reference carries intra-day gel drift).
+    """
+    import numpy as np
+    if isinstance(episode_frames, (list, tuple)):
+        k = max(1, max_frames // max(1, len(episode_frames)))
+        pooled = []
+        for fr in episode_frames:
+            fr = np.asarray(fr)
+            idx = np.linspace(0, fr.shape[0] - 1, min(k, fr.shape[0])).astype(np.int64)
+            pooled.append(fr[idx])
+        frames = np.concatenate(pooled, axis=0)
+    else:
+        frames = np.asarray(episode_frames)
+    return fuzzy_mode_background(frames, bin_w=bin_w, max_frames=max_frames)