the method of calculate the GLCM of a specific point in a image

Question

As we know, GLCM (Grey Level Co-occurrence Matrix) describes the texture characteristics of images. But in usual, the calculation of GLCM in OpenCV, matlab often aim on a picture. But now I just want to get GLCM value of every single point inside the image, but how to get it?

Answer 1

If I understand your problem correctly, then perhaps you can just set the pixels outside your region of interest to NaN - these pixels are ignored by MATLAB when calculating the GLCM.

For example:

>> im = eye(7)
im =
     1     0     0     0     0     0     0
     0     1     0     0     0     0     0
     0     0     1     0     0     0     0
     0     0     0     1     0     0     0
     0     0     0     0     1     0     0
     0     0     0     0     0     1     0
     0     0     0     0     0     0     1
>> graycomatrix(im)
ans =
    30     0     0     0     0     0     0     6
     0     0     0     0     0     0     0     0
     0     0     0     0     0     0     0     0
     0     0     0     0     0     0     0     0
     0     0     0     0     0     0     0     0
     0     0     0     0     0     0     0     0
     0     0     0     0     0     0     0     0
     6     0     0     0     0     0     0     0
>> im([1:10,13:16,21:24,28:29,34:37,41:49]) = NaN % Remove pixels outside ROI
im =
   NaN   NaN   NaN   NaN   NaN   NaN   NaN
   NaN   NaN   NaN   NaN     0   NaN   NaN
   NaN   NaN     1   NaN     0     0   NaN
   NaN     0     0     1     0     0   NaN
   NaN     0     0     0     1     0   NaN
   NaN   NaN     0     0   NaN   NaN   NaN
   NaN   NaN   NaN   NaN   NaN   NaN   NaN
>> warning('off', 'Images:graycomatrix:scaledImageContainsNan')
>> graycomatrix(im)
ans =
     6     0     0     0     0     0     0     2
     0     0     0     0     0     0     0     0
     0     0     0     0     0     0     0     0
     0     0     0     0     0     0     0     0
     0     0     0     0     0     0     0     0
     0     0     0     0     0     0     0     0
     0     0     0     0     0     0     0     0
     2     0     0     0     0     0     0     0
>> warning('on', 'Images:graycomatrix:scaledImageContainsNan')

Does that do what you need?