fullseye

vol_local_thickness — 3D feature op

• データ種: voxel → voxel
• 呼び出し: import fullseye as fs; fs.ledger.vol_local_thickness(vol_binary, spacing=None, max_radius=None) (実装を直接呼ぶなら import volops; volops.vol_local_thickness(vol_binary, spacing=None, max_radius=None)、台帳から引くなら ops3d.get("vol_local_thickness"))

使い方

Local thickness map: the diameter of the largest ball that covers each voxel.

For every foreground voxel this is max{ 2r : the voxel lies inside some ball of radius r that fits entirely in the foreground } — the classical granulometric size, and the quantity trabecular-bone and industrial-CT work calls local thickness (a pore’s local thickness is its diameter; a wall’s is its thickness). Computed from the exact distance transform: take the voxels whose distance is at least r as ball centres and paint the balls they cover, largest radius first.

★Distinct from vol_wall_thickness, which walks a single probe segment p0 -> p1 and returns a list of crossings. This one is a volume, so the thickness of every feature is available at once and can be histogrammed.

Pass spacing (sz, sy, sx) (or a :class:volio.VolumeMeta) and the result is in millimetres; otherwise in voxels. max_radius caps the search (in the same units); leave it None to derive it from the largest distance actually present, which costs one pass more but never saturates.

Applicability. (1) The foreground comes from a single threshold, so beam hardening or a brightness gradient biases the thickness across the volume — flatten first. (2) With anisotropic voxels the ball is a ball in millimetres, not in voxels, so spacing is not cosmetic. (3) A feature three voxels across is quantised at better than 30% only if you say so: report the voxel size next to any thickness number.

Returns a (D, H, W) float64 volume, 0 on the background.

Empty input (vol_binary with 0 elements) raises ValueError.

参考(サンプルデータ・文献)

• サンプルデータ カタログ(DL URL / ライセンス) — 2-D は skimage.data(BSD/public)+ 合成、3-D は実データ源(Stanford/PDS 等)の DL URL。
• 演算子の来歴・参考文献 — この op 族の元になった研究/手法の出典。

実行できる例(この op を実際に呼ぶ検証済みサンプル)

• ct_porosity_and_fibre_morphometry — py -3.11 examples_3d/ct_porosity_and_fibre_morphometry.py

型が繋がる次の op(voxel を入力に取れる)

voxel_to_mips · voxel_to_mesh · signed_distance_field · to_points · sobel3d · hessian3d · curvature_maps · edt_jfa

同カテゴリ(feature)

sobel3d · hessian3d · curvature_maps · edt_jfa · edt_jfa_vector · vol_frangi · vol_local_std · vol_orientation_coherence

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Provenance: volops.py — 3D operator registry. この per-op ノートは tools/opdocs.py md が自動生成(手編集しない)。

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

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