what is meant by GLCM MEAN (average) ?

It's the Gray Level Co-occurrence Matrix. It basically is kind of like a histogram of how many times a certain gray level occurs next to other gray levels in an image. Sometimes used in texture analysis. It is performed by the function graycomatrix() in the Image Processing Toolbox.

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angel 2013-2-23

编辑：angel 2013-2-23

在 MATLAB Online 中打开

ok sir... i know glcm is caculated as

glcm=graycomatrix(image);

i've divided the image into non overlapping blocks...the code is like this...

blockSizeR = 32;% Rows in block.
blockSizeC = 32; % Columns in block.

% Figure out the size of each block.

 wholeBlockRows = floor(rows / blockSizeR);
 wholeBlockCols = floor(columns / blockSizeC);
 fprintf('\nSize of whole block is %d x   %d\n\n',wholeBlockRows,wholeBlockCols); 
 % Now scan though, getting each block and putting it as a slice of a 3D array.
   blockNumber = 1;
 for row = 1 : blockSizeR : rows
  for col = 1 : blockSizeC : columns
    row1 = row;
    row2 = row1 + blockSizeR - 1;
    row2 = min(rows, row2);

% Determine starting and ending columns.

                col1 = col;
    col2 = col1 + blockSizeC - 1;
    col2 = min(columns, col2); % Don't let it go outside the image.
    % Extract out the block into a single subimage.
    oneBlock = grayImage(row1:row2, col1:col2);
               subplot(8,8,blockNumber);
               imshow(oneBlock);
               caption = sprintf('Block #%d\n of 64', blockNumber);
    title(caption, 'FontSize', fontSize);
    
               blockNumber = blockNumber + 1;
       end
   end
 figure,imshow(grayImage, []);
 title('original image');

sir plz can u tell me by writing a piece of code to calculate the GLCM MEAN..

Image Analyst 2013-2-23

Youssef, it's 8 by 8 because they chose to do so. I think intuitively you were expecting 256 by 256, right? That's what I would expect. But for whatever reason, they decided to make an 8 by 8 so the first row or column counts any pixel in the range 0-31 that is next to any other pixel with gray level 0-31, and so on.

Youssef Khmou 2013-2-23

编辑：Youssef Khmou 2013-2-23

Mr "Image Analyst": yes,as it is "comatrix" of M(m,n) "refers/related" to either covariance (cross correlation) , or simple meaning of Comtarix, size expected was n-by-n or m-by-m .

But this approach makes sens , unless one is concerned about very tiny details of individual pixels, then he can write a code suitable for that . ok thanks for the explanation

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Answer 3

Youssef Khmou 2013-2-23

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/64179-what-is-meant-by-glcm-mean-average#answer_76218

在 MATLAB Online 中打开

so you have two means : left hand side and right hand side ( reference : the link above ), lets take an example :

 I=imread('liftingbody.png'); 
 G=graycomatrix(I);
[m n]=size(G);
 GLCMl=0  % left 
 GLCMr=0; % right 
 for x=1:m
    for y=1:n
        GLCMl=GLCMl+x*G(x,y);
        GLCMr=GLCMr+y*G(x,y);
    end
end

it will give 1277276 and 1277165 , logical answer ?

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Youssef Khmou 2013-2-23

everyrthing is in the link angel :

i quote : " The left hand equation calculates the mean based on the reference pixels, i. It is also possible to calculate the mean using the neighbour pixels, j, as in the right hand equation. For the symmetrical GLCM, where each pixel in the window is counted once as a reference and once as a neighbour, the two values are identical."

angel 2013-2-23

thank u so much...

ur help means alot to me...

:)

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