Binarize adaptively🔗
Transforms any gray-level or color image to a binary image using one of the selected adaptive thresholding algorithms.
Inputs🔗
image
: Image to be thresholded. Color images will be converted to gray scale before applying the threshold.windowSize
: Size of the local window for adaptive threshold calculation.absoluteLevel
: Absolute threshold. The effect of this value depends on algorithm.relativeLevel
: Relative threshold. The effect of this value depends on algorithm.algorithm
: Adaptive thresholding algorithm.invert
: Iftrue
, inverts the result so that all foreground pixels become background and vice versa.
Outputs🔗
image
: Binary image
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enum
Algorithm
🔗 Thresholding algorithms.
Values:
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enumerator
RelativeToMean
🔗 Local threshold is calculated by multiplying the mean gray level around a pixel by relativeLevel and adding absoluteThreshold to the result.
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enumerator
RelativeToMeanAndStd
🔗 Local threshold is calculated by adding relativeThreshold times the standard deviation of the local gray levels to the mean gray level.
absoluteLevel will be added to the result.
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enumerator
WeightedMeanAndVariance
🔗 Local threshold t is calculated as \( t = \mu (1 + r (\sigma/\sigma_{\mathrm max} - 1)) + a \), where r stands for relativeThreshold, a for absoluteThreshold, and \( \sigma_{\mathrm max} \) for the maximum possible standard deviation, which is assumed to be 128.
In document image binarization, a good value for relativeThreshold is 0.34, whereas absoluteThreshold is typically zero.
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enumerator