calcHist

Image processingfunctionOpenCV 5.0.0

import { calcHist } from '@banou/opencv-wasm'

Use after await initOpenCV(). See the initialization and named imports guide.

Explore visually: Histogram equalization →

Redistribute grayscale intensities using their cumulative histogram.

VISUAL WALKTHROUGHColour

REFERENCE INPUTNarrow intensity range

The same scene stays here while the working view changes.

→

RESULTRedistributed intensities

Applying the monotone mapping stretches the occupied range and makes the objects easier to distinguish.

Computed teaching example on a 24 × 16 image. Small kernels and simplified settings keep each change visible; use the image laboratory for native OpenCV.

this variant supports only uniform histograms.

ranges argument is either empty vector or a flattened vector of histSize.size()*2 elements (histSize.size() element pairs). The first and second elements of each pair specify the lower and upper boundaries.

calcHist(images: MatVector, channels: IntVector, mask: Mat, hist: Mat, histSize: IntVector, ranges: FloatVector, accumulate: boolean): void;

2 available overloads

calcHist(images: MatVector, channels: IntVector, mask: Mat, hist: Mat, histSize: IntVector, ranges: FloatVector): void;

calcHist(images: MatVector, channels: IntVector, mask: Mat, hist: Mat, histSize: IntVector, ranges: FloatVector, accumulate: boolean): void;

images

images argument (MatVector).

channels

channels argument (IntVector).

mask

mask argument (Mat).

hist

Output destination, filled by the native operation. hist argument (Mat).

histSize

hist size argument (IntVector).

ranges

ranges argument (FloatVector).

accumulate

accumulate argument (boolean).

Upstream declaration ↗

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