The SSIM Index for Image Quality Assessment Zhou Wang, Alan C. Bovik, Hamid R. Sheikh and Eero P. Simoncelli The Structural SIMilarity (SSIM) index is a method for measuring the similarity between two images. The SSIM index can be viewed as a quality measure of one of the images being compared, provided the other image is regarded as of perfect quality. It is an improved version of the universal i