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Optimum Detection of Image-Adaptive Watermarking in the DCT Domain

Digital watermarking is an efficient and promising means to protect intellectual properties. Spread spectrum (SS) is one of the most widely used watermarking schemes, and can be further facilitated by adapting the watermark strength to the host signal. In this paper we address the problem of optimum blind detection of SS watermarks in the DCT domain, where Watson's non-linear perceptual model is used for the modulation of the watermarks. The basic idea is to transform the DCT coefficients to a perceptually uniform domain and perform Bayesian hypothesis testing in that domain. Simulation results show the superior performance of the proposed scheme over the conventional linear correlation detector (LCD).