完善 LiDAR–双天线 RTK 手眼标定仓库：补充旧式及多传感器数据导出、small_gicp/Open3D GICP 标定、结果复核与3D可视化流程，并整理三批数据和标定结果说明。

code/compare_extrinsics.py

@@ -0,0 +1,43 @@
+#!/usr/bin/env python3
+"""Compare two T_body_lidar JSON files in parameter space and on SE(3)."""
+
+import argparse
+import json
+from pathlib import Path
+
+import numpy as np
+from scipy.spatial.transform import Rotation
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("--reference", type=Path, required=True)
+    parser.add_argument("--candidate", type=Path, required=True)
+    parser.add_argument("--output", type=Path, required=True)
+    args = parser.parse_args()
+    reference = json.loads(args.reference.read_text(encoding="utf-8-sig"))
+    candidate = json.loads(args.candidate.read_text(encoding="utf-8-sig"))
+    a = np.asarray(reference["matrix_4x4"], dtype=float)
+    b = np.asarray(candidate["matrix_4x4"], dtype=float)
+    delta = np.linalg.inv(a) @ b
+    result = {
+        "convention": "delta = inverse(reference) @ candidate",
+        "reference": str(args.reference.resolve()),
+        "candidate": str(args.candidate.resolve()),
+        "candidate_minus_reference_translation_xyz_m": (b[:3, 3] - a[:3, 3]).tolist(),
+        "candidate_minus_reference_rpy_xyz_deg": (
+            np.asarray(candidate["rotation_rpy_deg_xyz"], float)
+            - np.asarray(reference["rotation_rpy_deg_xyz"], float)
+        ).tolist(),
+        "relative_translation_norm_m": float(np.linalg.norm(delta[:3, 3])),
+        "relative_rotation_deg": float(np.degrees(Rotation.from_matrix(delta[:3, :3]).magnitude())),
+        "relative_matrix_4x4": delta.tolist(),
+    }
+    args.output.parent.mkdir(parents=True, exist_ok=True)
+    args.output.write_text(json.dumps(result, ensure_ascii=False, indent=2), encoding="utf-8")
+    print(json.dumps(result, ensure_ascii=False, indent=2))
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())