how to subtract small window from an image by shifting pixel by pixel

I want to take small window from image and subtract that small window from whole image by shifting pixels by pixels. like for example I have 10x10 pixel image and I select a 3x3 pixels window from that image and subtract that 3x3 pixels image from whole 10x10 pixel image by shifting that mask window on whole image.

Answer 1

[Murugan C]

Hi,

inp_img = double(imread('cameraman.tif'));
figure
subplot(1,2,1);
imshow(inp_img,[]);
sub_mask_window = [14 25 16; 6 32 24; 35 13 44];  % creating mask window

for i = 1 : 2 : size(inp_img,1) - 2
    for j = 1 : 2 : size(inp_img,2) - 2
        subtract_img(i : i + 2, j : j + 2) = inp_img(i : i + 2, j : j + 2)... 
                                             - sub_mask_window;    % subtracting mask window with image
    end
end
subplot(1,2,2);
imshow(subtract_img)