Passing a matrix to graycomatrix

Could you please help me with the following question?

My code reads a DICOM image. The image is 512 * 512 uint 16.

The code draws an ROI on the image. After creating a mask, the code gets X and Y coordinates as well as the intensity of each pixel within the mask.

The result is a matrix of n by m, which its value corresponds to the image intensity. I want to know how I can pass this matrix to the graycomatrix function?

Answer 1

[Image Analyst]

See attached example.

[Nathan Armani]

Thank you Image Analyst. But, I could not find the answer to my question. I want to know how I should pass the matrix to the graycomatrix function.

I use the following code to create the matrix:

for i = 1:size(n) 
    iy = XROI(n(i, 1)); 
    ix = YROI(n(i, 1)); 
    intens = PixelValues(n(i, 1)); 
    imgmap(ix, iy) = intens;  
end

Where n represents the number of the pixels within the mask. XROI is the X-coordinates of all pixels within the mask. YROI is the Y-coordinates of all pixels within the mask. intens is intensity of the corresponding pixel.

The imgmap is the matrix

Then, should I pass the matrix as an image to the graycomatrix function?

If yes, which of the following code is correct:

NewImage = uint8(imgmap);

or given the original image is uint 16, I shoudl use:

NewImage = uint16(imgmap);

glcm = graycomatrix(NewImage, 'Offset', offsets);

or I can directly plugin the matrix:

glcm = graycomatrix(imgmap, 'Offset', offsets);

[Walter Roberson]

imgmap = zeros(max(YROI(n(:,1))), max(XROI(n(:,1))), 'like', PixelValues);

for i = 1:size(n, 1) 
    iy = XROI(n(i, 1)); 
    ix = YROI(n(i, 1)); 
    intens = PixelValues(n(i, 1)); 
    imgmap(iy, ix) = intens;  
end

glcm = graycomatrix(imgmap, 'Offset', offsets);

Note: you had x and y reversed. X is horizontal distance, which is column number. y is vertical distance, which is row number.

[Nathan Armani]

Thank you