Cocktail Watermarking for Digital Image Protection
Chun-Shien Lu, Shih-Kun Huang, Chwen-Jye Sze, and Hong-Yuan Mark Liao
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A novel image protection scheme called ``cocktail watermarking'' is proposed
in this paper. We
analyze and point out the inadequacy of the modulation techniques commonly used in ordinary
spread spectrum watermarking methods and the visual model-based ones. To resolve the inadequacy,
two watermarks which play complementary roles are simultaneously embedded into a host image.
The new watermarking scheme guarantees that, no matter what kind of attack is encountered, at
least one watermark can survive well. We also conduct a statistical analysis to derive the lower
bound of the worst likelihood that the better watermark (out of the two) can be extracted. With
this ``high'' lower bound, it is ensured that a ``better'' extracted watermark is always obtained. From
extensive experiments, results indicate that our cocktail watermarking scheme is remarkably effective
in resisting various attacks, including combined ones.