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A Nonlinear Detector for Optimal DCT-Domain Watermark Detection

A nonlinear detector is proposed for optimal DCT-domain watermark detection, which comes from a watermarking embedding algorithm based on the absolute value reordering rule of DCT coefficients. The performances of the nonlinear detector versus the linear detector, described by a measure of deflection coefficient, are evaluated in the watermark detection. Experimental results demonstrate that the proposed nonlinear detector is robust to some common attacks on the marked image, including JPEG compression, median filtering and addition of Gaussian noise.