Add relative-depth reprojection consistency metrics

simam3d_core.py

@@ -335,6 +335,40 @@ def project_world_points(
     return pixels, camera[:, 2].astype(np.float32), inside
 
 
+def reprojection_consistency(
+    points: np.ndarray,
+    depth: np.ndarray,
+    intrinsics: np.ndarray | None,
+    extrinsics: np.ndarray | None,
+) -> dict[str, float]:
+    """Compare fused-point depth against a view's relative depth prediction."""
+    depth = np.asarray(depth, dtype=np.float32)
+    if depth.ndim != 2:
+        raise ValueError("depth must be a 2-D map")
+    height, width = depth.shape
+    pixels, point_depth, inside = project_world_points(
+        points, intrinsics, extrinsics, width, height
+    )
+    if not inside.any():
+        return {"coverage": 0.0, "mean_absolute_error": 0.0, "median_absolute_error": 0.0}
+    raster = np.full((height, width), np.nan, dtype=np.float32)
+    pixel_x = np.clip(np.rint(pixels[inside, 0]).astype(np.int64), 0, width - 1)
+    pixel_y = np.clip(np.rint(pixels[inside, 1]).astype(np.int64), 0, height - 1)
+    for x, y, value in zip(pixel_x, pixel_y, point_depth[inside]):
+        if not np.isfinite(raster[y, x]) or value < raster[y, x]:
+            raster[y, x] = value
+    valid = np.isfinite(raster)
+    if not valid.any():
+        return {"coverage": 0.0, "mean_absolute_error": 0.0, "median_absolute_error": 0.0}
+    target = 1.0 - normalize_map(depth)
+    error = np.abs(raster[valid] - target[valid])
+    return {
+        "coverage": float(valid.mean()),
+        "mean_absolute_error": float(error.mean()),
+        "median_absolute_error": float(np.median(error)),
+    }
+
+
 def depth_to_camera_points(
     depth: np.ndarray,
     intrinsics: np.ndarray | None = None,