支持主机桥接后固定δt与旋转先验，并落盘运动对供可视化直读。

Co-authored-by: Cursor <cursoragent@cursor.com>

tools/export_motion_pairs_for_viz.py

@@ -0,0 +1,111 @@
+#!/usr/bin/env python3
+"""Build motion_pairs.json next to an existing summary without re-solving extrinsic.
+
+Use this once for older calibration outputs that predate automatic pair caching.
+"""
+
+from __future__ import annotations
+
+import argparse
+import json
+import sys
+from pathlib import Path
+
+import numpy as np
+
+ROOT = Path(__file__).resolve().parents[1]
+if str(ROOT) not in sys.path:
+    sys.path.insert(0, str(ROOT))
+
+from imu_lidar.imu_audit import audit_imu
+from imu_lidar.imu_io import load_imu_samples
+from imu_lidar.keyframes import build_keyframes
+from imu_lidar.lidar_io import load_lidar_frames
+from imu_lidar.motion_pairs import build_motion_pairs
+from imu_lidar.motion_pairs_io import build_motion_pairs_payload, save_motion_pairs
+
+
+def _load_summary_meta(summary_path: Path) -> tuple[float, np.ndarray, str]:
+    summary = json.loads(summary_path.read_text(encoding="utf-8"))
+    delta_t = float(summary.get("time_offset_s") or 0.0)
+    session = (summary.get("details") or {}).get("sessions", [{}])[0]
+    session_id = str(session.get("session_id") or summary_path.parent.name)
+    bias = np.asarray(
+        (session.get("imu_audit") or {}).get("gyro_bias_rad_s")
+        or (session.get("joint") or {}).get("gyro_bias_rad_s")
+        or [0.0, 0.0, 0.0],
+        dtype=float,
+    ).reshape(3)
+    return delta_t, bias, session_id
+
+
+def export_one(
+    *,
+    lidar: Path,
+    imu: Path,
+    summary: Path,
+    output: Path | None,
+    min_rotation_deg: float,
+    min_translation_m: float,
+) -> Path:
+    delta_t, bias_from_summary, session_id = _load_summary_meta(summary)
+    imu_series = load_imu_samples(imu)
+    # Prefer freshly audited bias if summary bias is missing/zeros.
+    if float(np.linalg.norm(bias_from_summary)) < 1e-12:
+        bias = audit_imu(imu_series).gyro_bias_rad_s
+    else:
+        bias = bias_from_summary
+
+    frames = load_lidar_frames(lidar)
+    keyframes = build_keyframes(
+        frames,
+        min_translation_m=min_translation_m,
+        min_rotation_deg=min_rotation_deg,
+    )
+    pair_set = build_motion_pairs(
+        session_id=session_id,
+        keyframes=list(keyframes.frames),
+        keyframe_indices=keyframes.indices,
+        imu=imu_series,
+        delta_t_s=delta_t,
+        gyro_bias_rad_s=bias,
+        min_rotation_deg=min_rotation_deg,
+        min_translation_m=min_translation_m,
+    )
+    prepared = [
+        {
+            "session_id": session_id,
+            "time_offset_s": delta_t,
+            "gyro_bias_rad_s": np.asarray(bias, dtype=float).reshape(3),
+            "pairs": pair_set.pairs,
+        }
+    ]
+    payload = build_motion_pairs_payload(prepared_sessions=prepared)
+    out = output or (summary.parent / "motion_pairs.json")
+    save_motion_pairs(out, payload)
+    print(f"wrote {out} ({len(pair_set.pairs)} pairs, session={session_id}, dt={delta_t:.6f})")
+    return out
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("--lidar", type=Path, required=True)
+    parser.add_argument("--imu", type=Path, required=True)
+    parser.add_argument("--summary", type=Path, required=True)
+    parser.add_argument("--output", type=Path, default=None, help="Default: <summary_dir>/motion_pairs.json")
+    parser.add_argument("--min-pair-rotation-deg", type=float, default=2.0)
+    parser.add_argument("--min-pair-translation-m", type=float, default=0.3)
+    args = parser.parse_args()
+    export_one(
+        lidar=args.lidar,
+        imu=args.imu,
+        summary=args.summary,
+        output=args.output,
+        min_rotation_deg=args.min_pair_rotation_deg,
+        min_translation_m=args.min_pair_translation_m,
+    )
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())