vol_equalize — 3D `gray` op

• 数据种类:voxel → voxel

• 调用: import fullseye as fs; fs.ledger.vol_equalize(vol, nbins=256, mask=None)(要直接调用实现,import volgray; volgray.vol_equalize(vol, nbins=256, mask=None);从台账取用则 ops3d.get("vol_equalize"))

用法

体的直方图均衡(HALCON equ_histo_image)。

> 以下的详细说明为原文 —— 摘要与标题已翻译。

Builds an *nbins*-bin histogram over the volume's [min, max] range, takes its cumulative distribution as a monotone LUT, and maps every voxel through it — the output lives in (0, 1] and its histogram is (approximately) flat. With *mask* (thresholded at > 0.5, the volops convention) the histogram is computed from the masked voxels only while the LUT is applied to the whole volume — exactly the HALCON reduce_domain + equ_histo_image domain behaviour, and the right tool when a dominant background (e.g. air around a CT subject) would otherwise swallow the whole dynamic range.

A constant volume is returned unchanged — normalising a flat volume would amplify floating-point dust into full-scale garbage (fail-honest, not fail-loud; see the module docstring).

Parameters

vol : array_like, shape (D, H, W)

Input volume (coerced to float64; NaN/Inf rejected).

nbins : int

Histogram bins, >= 2. More bins = finer LUT (the mapping is

piecewise-constant per bin — an approximation, documented above).

mask : array_like, shape (D, H, W), optional

Histogram domain. Must match *vol*'s shape and select at least one

voxel (an empty domain has no histogram — fail-closed).

Returns

ndarray, shape (D, H, W), float64

The equalised volume in [0, 1] (constant input: the input itself).

Raises

ValueError

Non-3-D / non-finite input, nbins < 2, a mask shape mismatch, or

an empty mask.

参考(示例数据、文献)

• 示例数据目录(下载 URL / 许可证) —— 2-D 用 skimage.data(BSD/公有领域)加合成图,3-D 给出真实数据源(Stanford/PDS 等)的下载 URL。

• 算子来历与参考文献 —— 该算子族所依据的研究/方法出处。

可运行的示例(实际调用该算子并已验证的样例)

• gray_window_level — py -3.11 examples_3d/gray_window_level.py

类型可衔接的下一个算子(可接受 `voxel` 作为输入)

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

同类别(`gray`)

vol_window_level · vol_gamma · vol_stretch

*Provenance: volgray.py — 3D 算子登记表。本条目由 tools/opdocs.py md 自动生成(请勿手工编辑)。*

vol_equalize — 3D gray op

用法