Copyright protection of images using human visual masking on DCT-based watermarking

Abstract

In this paper a new watermarking algorithm for digital images operating in the frequency domain is presented: a sequence of pseudo-random real numbers is embedded in a selected set of DCT coefficients. After embedding, the watermark is adapted to the image to be signed by exploiting the masking characteristics of the Human Visual System (HVS) in order to achieve watermark invisibility without diminishing its robustness. Experimental results demonstrate that the watermark is robust to several signal processing techniques and geometric distortions.