Visibility of DCT basis functions: effects of contrast masking

The discrete cosine transform (DCT) is a standard method by which images may be compressed. Initially, the image is divided into 8×8-pixel blocks, each of which is then transformed into its DCT, which is an 8×8 matrix of coefficients. One image-dependent factor influencing the detectability of DCT basis functions is contrast masking. The authors present data which indicate that sensitivity to a particular coefficient´s quantization error is affected by the magnitudes of other coefficients. They propose a revision of Model O to account for between-coefficient contrast masking