Image: Lichtenstein jpeg difference

Description: The picture shows the difference pixel-by-pixel between an image and its JPEG compressed version: white=no-difference; black=big-difference The original image is Image:Lichtenstein img processing test.png, that I have renamed castle.png on my hard-disk to make it simpler. Then I have converted it to JPEG using the "convert" utility by ImageMagik, with the following command: convert -quality 50 castle.png castle.jpg Then I have used the following Matlab code: %read original image original=imread('castle.png'); %read compressed image compressed=imread('castle.jpg'); original=im2double(original); compressed=im2double(compressed); error=abs(original-compressed); %amplify the error for each color layer error(:,:,1)=imadjust(error(:,:,1)); error(:,:,2)=imadjust(error(:,:,2)); error(:,:,3)=imadjust(error(:,:,3)); %invert the picture error=1-error; %write it to a file imwrite(error,'castle_error.png');
Title: Lichtenstein jpeg difference
Credit: Own work
Author: Alessio Damato
Usage Terms: Creative Commons Attribution-Share Alike 3.0
License: CC-BY-SA-3.0
License Link: http://creativecommons.org/licenses/by-sa/3.0/
Attribution Required?: Yes