Mask building for perceptually hiding frequency embedded watermarks

The interest in image watermarking techniques has rapidly grown during the years. Two requirements needed to be satisfied to use watermarking techniques for copyright protection are: unperceivability and robustness against image processing algorithms and forgery attacks. In particular, it is widely accepted that the exploitation of the characteristics of the human visual system should greatly help in satisfying both these requirements. Some solutions to the problem of building some perceptual masks for better hiding watermarks embedded in the full-frame DCT domain are presented. The results support the validity of the approach.