Abdulhakeem Othman:
I'm not really in the compression field - so I'm not really sure - but
I think PSNR really only makes sense for monochrome images. There may
be color quality metrics that you can use. Failing that, I'd
calculate the average Delta E between your standard reference image
and your test image. I think this is pretty close in concept to the
PSNR, just for color instead of monochrome. Basically it gives you
the average color difference between images. To do this, convert your
two images to LAB color space:
(from URL
http://www.mathworks.com/products/image/demos.html?file=/products/demos/shipping/images/ipexfabric.html)
cform = makecform('srgb2lab');
lab_image = applycform(imageArray,cform);
Then calculate deltaE = sqrt(deltaL.^2 + deltaA.^2 + deltaB.^2)/
numberOfPixels
where
deltaL = L_image1 - L_image2
deltaA = A_image1 - A_image2
deltaB = B_image1 - B_image2