estimate_point_normals — 3D transform op

Data kinds: pointsnormals

Call: import fullseye as fs; fs.ledger.estimate_point_normals(points, k=16, viewpoint=None) (to call the implementation directly, import match3d; match3d.estimate_point_normals(points, k=16, viewpoint=None); from the registry, ops3d.get("estimate_point_normals"))

Usage

Point set (N,3) → unit normals (the smallest eigenvector of the local k-neighbourhood covariance = PCA).

> The detailed description below is the original text — the summary and the headings are translated.

FPFH/SHOT/点-面 ICP が要る法線を raw 点群から生成。向きの規約は 2 面:

viewpoint=None(既定)= 重心から外向き(閉じた物体の全周点群向け)/

viewpoint 指定 = 視点(センサ)向き(Hoppe 1992 / PCL 規約。単一視点スキャンの

可視面はセンサ側を向くのが物理的に正しい。pointcloud.estimate_normals と同規約)。

旧版(〜2026-08-30)は viewpoint 指定でも「視点から遠ざける」符号で、単一視点

スキャンという本来用途で全点が裏返っていた。返り値 normals (N,3)。

手順: `cKDTree で各点の k 近傍(自分自身を含む。k > N` なら N に切り詰め)を取り、

その共分散の最小固有ベクトルを法線にする。返り値 `(N,3)` float64 の単位ベクトル。

`viewpoint` は 3 次元の座標(センサ位置)。点数が 3 未満・近傍が同一直線上だと法線は

不定のまま返る(検証は無い)。`k` が小さいとノイズに弱く、大きいと角が丸まる。

後段: `icp_point2planedst_normalsrender_shaded 用の法線、normals_to_egi`。

`pointcloud.estimate_normals(台帳 estimate_normals`)と同じ規約。

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)

fpfh_correspondencepy -3.11 examples_3d/fpfh_correspondence.py

Ops the type connects to (they accept normals as input)

icp_point2plane · compute_fpfh · shot_descriptor · fuse_to_voxel · reflect · refract · normal_consistency · ransac_cylinder

Same category (transform)

points_to_voxel · gaussians_to_voxel · mesh_to_voxel · mesh_to_points · depth_to_points · voxel_to_mips · voxel_to_mesh · tsdf_from_depth


*Provenance: match3d.py — 3D operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*

© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.