1. A method comprising: accessing a first set of transform domain variances for a first image and a second set of transform domain variances for a second image, the second image comprising a decompressed representation of the first image; determining a mean squared error between the first image and the second image; accessing a set of adaptation constants; and computing a measure of visual quality of the second image based on the first and second sets of transform domain variances, the mean square error, the set of adaptation constants, and a number of bits that represent each pixel of the second image.