vol_equalize — 3D gray op

• Data kinds: voxel → voxel

• Call: import fullseye as fs; fs.ledger.vol_equalize(vol, nbins=256, mask=None) (implementation को सीधे call करना हो तो import volgray; volgray.vol_equalize(vol, nbins=256, mask=None), registry से लेना हो तो ops3d.get("vol_equalize"))

उपयोग

volume का histogram equalisation (HALCON equ_histo_image)।

> नीचे का विस्तृत विवरण मूल text में है — सारांश और headings का अनुवाद हो चुका है।

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.

संदर्भ (sample data, साहित्य)

• Sample data catalog (DL URL / license) — 2-D के लिए skimage.data (BSD/public) + synthetic, 3-D के लिए real data sources (Stanford/PDS आदि) के DL URL।

• Operators का स्रोत और संदर्भ — इस op family के मूल research/methods के स्रोत।

चलाए जा सकने वाले उदाहरण (verified samples जो सच में यह op call करते हैं)

• gray_window_level — py -3.11 examples_3d/gray_window_level.py

वे अगले ops जिनसे type जुड़ता है (voxel को input के रूप में लेते हैं)

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

इसी category के (gray)

vol_window_level · vol_gamma · vol_stretch


*Provenance: volgray.py — 3D operator registry. यह per-op note tools/opdocs.py md से अपने-आप generate होता है (हाथ से edit न करें)।*

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