Double-sided watermark embedding and detection

Spread-spectrum schemes embed additive or multiplicative watermarks into the host contents for copyright protection. However, their performances are reduced by the interference from the host contents. Thus, in this work, we introduce a simple double-sided technique to utilize this interference for performance improvements. Different from the previous host interference rejection schemes, it does not reject the host interference. However, it can also achieve great performance enhancement over the traditional spread-spectrum schemes. Moreover, due to this nice property of not rejecting the host interference, it has a big advantage over the host interference rejection schemes in that the perceptual analysis can be easily implemented for our scheme to improve the perceptual quality of the watermarked contents. Our technique is effectively employed in both additive and multiplicative spread-spectrum schemes. Finally, its performance advantage is demonstrated through both theoretical and empirical comparisons.