nearest_neighbor_flow — 3D `scene_flow3d` op

• Data kinds: points × points → flow_scattered

• Call: import fullseye as fs; fs.ledger.nearest_neighbor_flow(pts0, pts1) -> 'np.ndarray' (to call the implementation directly, import scene_flow3d; scene_flow3d.nearest_neighbor_flow(pts0, pts1) -> 'np.ndarray'; from the registry, ops3d.get("nearest_neighbor_flow"))

Usage

The 3-D displacement vector field (N, 3) from each point of pts0 to its nearest neighbour in pts1.

For each point p of pts0, finds the nearest neighbour q in pts1 with cKDTree and returns the displacement q - p. Element counts may differ, N != M. Only when the displacement is much smaller than the local point spacing (small motion) does it hit "the true correspondence of point i" — with large displacements the nearest neighbour sticks to another point (an honest limitation; for regularisation combine with smooth_flow).

Args:

pts0: (N, 3) point cloud at time 0.

pts1: (M, 3) point cloud at time 1.

Returns:

(N, 3) displacement vector field (same row order as pts0).

Raises:

ValueError: invalid shape, or pts1 empty while pts0 is non-empty.

References (sample data, literature)

• Sample-data catalog (download URLs / licences) — 2-D uses skimage.data (BSD/public domain) plus synthetic images; 3-D lists download URLs for real data sources (Stanford, PDS, …).

• Operator provenance and references — the sources of the research/methods this op family came from.

Runnable examples (verified samples that actually call this op)

• scene_flow_rigid — py -3.11 examples_3d/scene_flow_rigid.py

Ops the type connects to (they accept `flow_scattered` as input)

fuse_to_voxel

Same category (`scene_flow3d`)

rigid_flow · smooth_flow

*Provenance: scene_flow3d.py — 3D operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*

nearest_neighbor_flow — 3D scene_flow3d op