feature op• 資料種類:voxel → voxel
• 呼叫: import fullseye as fs; fs.ledger.vol_local_thickness(vol_binary, spacing=None, max_radius=None)(要直接呼叫實作,import volops; volops.vol_local_thickness(vol_binary, spacing=None, max_radius=None);從台帳取用則 ops3d.get("vol_local_thickness"))
局部厚度圖 —— 能覆蓋每個體素的最大球的直徑。
> 以下的詳細說明為原文 —— 摘要與標題已翻譯。
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.
• 範例資料目錄(下載 URL / 授權) —— 2-D 用 skimage.data(BSD/公有領域)加合成圖,3-D 給出真實資料源(Stanford/PDS 等)的下載 URL。
• 運算子來歷與參考文獻 —— 該運算子族所依據的研究/方法出處。
• ct_porosity_and_fibre_morphometry — py -3.11 examples_3d/ct_porosity_and_fibre_morphometry.py
voxel 作為輸入)voxel_to_mips · voxel_to_mesh · signed_distance_field · to_points · sobel3d · hessian3d · curvature_maps · edt_jfa
feature)sobel3d · hessian3d · curvature_maps · edt_jfa · vol_frangi · vol_local_std · vol_orientation_coherence · vol_euler_number
*Provenance: volops.py — 3D 運算子登記表。本條目由 tools/opdocs.py md 自動產生(請勿手動編輯)。*
© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.