how can find altered pixels?

Q
qasim mohammed · Feb 5, 2024 · 1.9K views
Question
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  
Expert Answer
Profile picture of Neeta Dsouza
Neeta Dsouza PhD Expert
Answered Aug 14, 2026
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)

100% Run Guarantee 3-Hour Fast-Track Delivery

Need a Custom Version or Complete Simulation for This Problem?

Our 500+ PhD engineers build, debug, and optimize working MATLAB scripts and Simulink (.slx) models tailored to your exact assignment rubrics with zero plagiarism.

Tested on MATLAB R2024b / R2026a
Turnitin 0% Plagiarism Report
Free 7-Day Revisions Guarantee
Have a different question? Ask here

Get a Free Consultation or a Sample Assignment Review!