Using perceptual distance to improve the selection of dirty paper trellis codes for watermarking

Previous watermarking research based on dirty paper trellis coding [G.L. Miller et al., 2002] proposed a method for informed coding by which the best code from the set of codewords representing the message was selected based on maximizing the linear correlation between the codewords and the original cover Work. However, this does not guarantee that the linear correlation is maximized in the watermarked cover Work. This is because the chosen codeword must be attenuated due to fidelity constraints. Since there is no clear relationship between linear correlation and fidelity, a codeword that is chosen to maximize linear correlation may be very difficult to embed if it is perceptually very different from the underlying cover Work. We show that this is in fact the case and suggest a solution to this problem that involves a cost function that is a linear combination of perceptual distance and linear correlation. Experimental results demonstrate 50% and 25% improvements in bit and message error rates respectively.