medial_axis_points — 3D `medial` op

• Data kinds: voxel → points

• Call: import fullseye as fs; fs.ledger.medial_axis_points(vol, min_radius=0.0) (to call the implementation directly, import medial; medial.medial_axis_points(vol, min_radius=0.0); from the registry, ops3d.get("medial_axis_points"))

• Return value through the ledger: fullseye.ledger.medial_axis_points(...) returns **only the declared out type points** (the underlying function also returns auxiliary values). When you need what was dropped, use fullseye.ledger.medial_axis_points.raw(...) or call medial.medial_axis_points directly.

• Underlying return: (points, radii)

Usage

Turn the medial voxels into a point set with their local radius (= that point's EDT value). Returns (points, radius).

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

太い部分は面状、細い部分は線状に分布する medial 点を (M,3) の座標(z,y,x)と、それぞれの

局所半径 (M,) として返す。半径最大の点は形状の最も「内側」= 中心を指す。

Args:

vol: バイナリ voxel(bool / 0-1 の 3D)。

min_radius: この半径以下の点を除外(ノイズ抑制)。

Returns:

points (float64, (M,3)): medial voxel 座標(z, y, x)。

radius (float64, (M,)): 各点の EDT 値(= 局所内接半径)。

手順: `distance_ridge(vol, min_radius) で得た ridge_mask の np.argwhere`

(配列 index、行は z-major の辞書順で決定的)と、その位置の `edt` 値を返す。

座標は voxel index で spacing は掛けない(物理座標が要るなら呼び手で

`points * (sz, sy, sx)`、半径も同様に等方 spacing を掛ける)。

引数と検証: `vol` は 3-D(非ゼロ = 前景)。3-D でない・空・NaN/Inf は

`ValueError、min_radius < 0 も ValueError。radius` は

`> min_radius の点だけ(境界 voxel は EDT が 1 以下なので min_radius=1` で

外殻ノイズをほぼ落とせる)。

端の挙動: 前景が無い、または全点が `min_radius 以下なら points は (0, 3)`、

`radius は (0,)` の空配列(エラーにしない)。

使いどころ: `medial_match の半径分布、点群 op(smallest_sphere3` /

`fit_line3 等)への橋渡し、np.argmax(radius)` で最大内接球の中心を取る。

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)

• medial_topology — py -3.11 examples_3d/medial_topology.py

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

points_to_voxel · gaussians_to_voxel · estimate_point_normals · to_points · match_points_ncc · match_pca · moment_axes · icp_point2point_3d

Same category (`medial`)

distance_ridge · skeletonize_vol · topology_signature · medial_match · skeleton_junctions3d · skeleton_endpoints3d · skeleton_prune3d · skeleton_branches3d

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

medial_axis_points — 3D medial op