{
  "episode_id": "20260708_155328",
  "metric": "min distance in pixels from projected wrist and index tip to a skin-colored pixel",
  "not_ground_truth": true,
  "lens": "equidistant fisheye r=f*theta, camera roll +90 deg",
  "window_rgb_index": [
    1404,
    1476
  ],
  "window_t_rel_s": 24.0,
  "window_note": "23.4\u201324.6 s, both-hands demo, clustered wrist speed. Not the single fastest sample.",
  "peak_left_wrist_speed_m_s": 2.808,
  "frames_used": 25,
  "factory_rgb_alignment_ms": -9.941,
  "pixel_shift_at_factory_offset_p50": 4.7,
  "offsets": [
    {
      "offset_ms": -40,
      "n": 184,
      "skin_px_p50": 4.5,
      "skin_px_p90": 45.3
    },
    {
      "offset_ms": -35,
      "n": 184,
      "skin_px_p50": 4.5,
      "skin_px_p90": 45.3
    },
    {
      "offset_ms": -30,
      "n": 184,
      "skin_px_p50": 4.5,
      "skin_px_p90": 45.3
    },
    {
      "offset_ms": -25,
      "n": 184,
      "skin_px_p50": 4.5,
      "skin_px_p90": 45.3
    },
    {
      "offset_ms": -20,
      "n": 184,
      "skin_px_p50": 3.6,
      "skin_px_p90": 45.5
    },
    {
      "offset_ms": -15,
      "n": 184,
      "skin_px_p50": 3.6,
      "skin_px_p90": 45.5
    },
    {
      "offset_ms": -10,
      "n": 184,
      "skin_px_p50": 3.6,
      "skin_px_p90": 45.5
    },
    {
      "offset_ms": -5,
      "n": 188,
      "skin_px_p50": 3.5,
      "skin_px_p90": 46.8
    },
    {
      "offset_ms": 0,
      "n": 188,
      "skin_px_p50": 3.5,
      "skin_px_p90": 46.8
    },
    {
      "offset_ms": 5,
      "n": 188,
      "skin_px_p50": 3.5,
      "skin_px_p90": 46.8
    },
    {
      "offset_ms": 10,
      "n": 184,
      "skin_px_p50": 3.4,
      "skin_px_p90": 45.7
    },
    {
      "offset_ms": 15,
      "n": 184,
      "skin_px_p50": 3.4,
      "skin_px_p90": 45.7
    },
    {
      "offset_ms": 20,
      "n": 184,
      "skin_px_p50": 3.4,
      "skin_px_p90": 45.7
    },
    {
      "offset_ms": 25,
      "n": 184,
      "skin_px_p50": 3.4,
      "skin_px_p90": 45.7
    },
    {
      "offset_ms": 30,
      "n": 184,
      "skin_px_p50": 3.1,
      "skin_px_p90": 43.9
    },
    {
      "offset_ms": 35,
      "n": 184,
      "skin_px_p50": 3.1,
      "skin_px_p90": 43.9
    },
    {
      "offset_ms": 40,
      "n": 184,
      "skin_px_p50": 3.1,
      "skin_px_p90": 43.9
    }
  ],
  "proxy_valid": true,
  "chosen_offset_ms": 0,
  "chosen_reason": "Skin-color distance stays about 3–5 px across ±40 ms, so the proxy cannot choose a millisecond. Factory -9.9 ms moves the projected wrist 4.7 px (p50) in this window. Applied offset stays 0. p90 near 46 px is the remaining edge error. Not a checkerboard."
}