AN IMPROVED SUBSPACE BASED ASYMMETRIC WATERMARKING SCHEME FOR COPY PROTECTION

摘要

Asymmetric watermarking schemes based on subspace have been shown to be secure from projection attacks. The benefit comes from that their detection keys have host signal components which perceptibly degrade the host signals when the watermarks are made undetectable. These schemes, however, suffer high false detection probability because of the very host signal components. In this paper, we propose an improved asymmetric watermarking scheme for copy protection of digital images by determining the amount of the host signal components to be contained in the watermark detection key for both security from projection attacks and low false detection probability. The simulation results show that the proposed algorithm effectively lowers false detection probability while maintaining security against projection attacks.