How to calculate the contrast energy, entropy of a ROI(Region of interest) of an image using GLCM feature extractactions method?

I need to extract GLCM features like energy entropy contrast among others of the REGION OF INTEREST ONLY excluding the black background,i managed to extract those features for the entire image but i only need them for the region of interest knowing that everything else will be black

 % Loop over all GLCMs
for k = 1:nglcm 
    currentGLCM = glcm(:,:,k);
    glcmMean(k) = mean2(currentGLCM);

    % For symmetric GLCMs, uX = uY
    uX(k)   = sum(I.*currentGLCM(sub));
    uY(k)   = sum(J.*currentGLCM(sub));
    sX(k)   = sum((I-uX(k)).^2.*currentGLCM(sub));
    sY(k)   = sum((J-uY(k)).^2.*currentGLCM(sub));

    out.contrast(k)             = sum(abs(I-J).^2.*currentGLCM(sub)); %OK
    out.dissimilarity(k)        = sum(abs(I - J).*currentGLCM(sub)); %OK
    out.energy(k)               = sum(currentGLCM(sub).^2); % OK
    out.entropy(k)              = -nansum(currentGLCM(sub).*log(currentGLCM(sub))); %OK
    out.inverseDifference(k)    = sum(currentGLCM(sub)./( 1 + abs(I-J) )); %OK
    out.homogeneity(k)          = sum(currentGLCM(sub)./( 1 + (I - J).^2)); %OK

[Rena Berman]

(Answers Dev) Restored edit

Answer 1

[Phuong Nguyen]

Did you solve this problem? I am having the same problem with you and cant get over it. If you done, could you please teach me? Thank you.

[Binu]

Force all pixel values outside your region of interest as a 'NaN'. The graycomatrix methods by default ignores any pixel pairs having a 'NaN' value.

https://www.mathworks.com/help/images/ref/graycomatrix.html#namevaluepairarguments (read Algorithms section)

Answer 2

[Image Analyst]

graycoprops() returns 4 measurements. Will that do?

[Elias Unk]

Yes i think it'll do if it'll only extract features from the lesion area not the entire image.

Answer 3

[Binu]

The graycomatrix function has a '*GrayLimits*' argument where you can specify a two-element vector [low high] which is used for scaling the image and creating NumLevels. Grayscale values less than or equal to low are scaled to 1. You could set that yours to [0.1 1] for your case.

[Usuma]

But in this method black pixels of ROI are neglected. Is there any accurate solution for this? Can anybody help?

[Image Analyst]

Then don't use GrayLimits.