Performs image segmentation and color reduction using Otsu clustering on grayscale images.


#include "ltwrappr.h"

virtual L_INT LBitmap::OtsuThreshold(nClusters)


L_INT nClusters

The number of colors in the output image. Possible values are range from 2 to 255.


Value Meaning
SUCCESS The function was successful.
< 1 An error occurred. Refer to Return Codes.


This function works only with grayscale images. If the input image is colored it will be converted to a grayscale image.

Otsu clustering is performed by making each cluster as compact as possible so as to minimize overlap. If one adjusts a threshold one way, the spread of one cluster gets larger and the spread for the second cluster gets smaller. Different threshold values are tried until the one is found which produces the minimum combined spread.

Otsu thresholding is typically used as a way to binarize an image. It is best when used on an image that has a bimodal histogram (Clusters = 2).

This function can only process entire images. It does not support regions.

This function supports 8 and 16-bit grayscale images.

Otsu Thresholding Function - Before

Otsu Thresholding Function - Before

Otsu Thresholding Function - After

Otsu Thresholding Function - After

View additional platform support for this Otsu Thresholding function.

Required DLLs and Libraries


Win32, x64.

See Also


#if defined (LEADTOOLS_V19_OR_LATER) 
L_INT LBitmap__OtsuThresholdExample(L_VOID) 
    L_INT nRet ; 
    LBitmap LeadBitmap ; 
    nRet = LeadBitmap.Load(MAKE_IMAGE_PATH(TEXT("ImageProcessingDemo\\NaturalFruits.jpg")), 0,ORDER_BGR); 
    if(nRet !=SUCCESS) 
        return nRet ; 
    nRet = LeadBitmap.OtsuThreshold(4); 
    return SUCCESS ; 
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