MATLAB: How to measure % intensity difference between 2 image

Question

Hi,

May i know how to calculate the percentage intensity difference between 2 image of the same size. Then i need to apply this % of intensity different to another image of different size.

Answer 1

imDiff = image1 - image2;
imSum = image1 + image2;  
percentDiff = 200 * mean(imDiff(:)) / mean(imSum(:));
imAdjusted = (1 + percentDiff/100) * image3;