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bundles / skimage 0.26.1rc0.dev0+git20260530.b607368ff / skimage / filters / thresholding / threshold_multiotsu

function

skimage.filters.thresholding:threshold_multiotsu

source: /dev/scikit-image/src/skimage/filters/thresholding.py :1230

Signature

def   threshold_multiotsu ( image = None ,  classes = 3 ,  nbins = 256 ,  * ,  hist = None )

Summary

Generate classes-1 threshold values to divide gray levels in image, following Otsu's method for multiple classes.

Extended Summary

The threshold values are chosen to maximize the total sum of pairwise variances between the thresholded graylevel classes. See Notes and [1] for more details.

Either image or hist must be provided. If hist is provided, the actual histogram of the image is ignored.

Parameters

image : (M, N[, ...]) ndarray, optional

Grayscale input image.

classes : int, optional

Number of classes to be thresholded, i.e. the number of resulting regions.

nbins : int, optional

Number of bins used to calculate the histogram. This value is ignored for integer arrays.

hist : array, or 2-tuple of arrays, optional

Histogram from which to determine the threshold, and optionally a corresponding array of bin center intensities. If no hist provided, this function will compute it from the image (see notes).

Returns

thresh : array

Array containing the threshold values for the desired classes.

Raises

: ValueError

If image contains less grayscale value then the desired number of classes.

Notes

This implementation relies on a Cython function whose complexity is , where is the number of histogram bins and is the number of classes desired.

If no hist is given, this function will make use of skimage.exposure.histogram, which behaves differently than np.histogram. While both allowed, use the former for consistent behaviour.

The input image must be grayscale.

Examples

from skimage.color import label2rgb
from skimage import data
image = data.camera()
thresholds = threshold_multiotsu(image)
regions = np.digitize(image, bins=thresholds)
regions_colorized = label2rgb(regions)
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Aliases

  • skimage.filters.threshold_multiotsu

Referenced by

This package