how can find altered pixels

Hi Dears I have two images the first is the original while the second is the watermarked image. I altered some pixels in the watermarked image , then I extracted the watermark from the altered image and compared with the original wateremark using MSE , I couldnt find the exact altered pixels, also I want a way to calculate the values of False positive (FP), false negative (FN) and average of detection rate . with many thanks

Answer 1

[Walter Roberson]

idx = find(OriginalImage ~= WaterMarkedImage);
[coords{1:ndims(OriginalImage)}] = ind2sub(size(OriginalImage), idx);
row_col_plane_idx = cell2mat(coords);

Now row_col_plane_idx(K,1) is a row number of a mismatch, row_col_plane_idx(K,2) is the corresponding column, row_col_plane_idx(K,3) is the corresponding color plane (R, G, B)

[qasim mohammed]

thank u so much for your rapid response, I will run the code to see

[Walter Roberson]

I made a small correction, ndims instead of ndim

[qasim mohammed]

okay, it run , many thanks