| 摘要 |
A system and method of retrieving a watermark in a watermarked signal are disclosed. The watermarked signal comprises odd and even overlapped blocks where the watermark is contained in the even blocks. The method comprises, for each k-th even block, subtracting the two adjacent odd numbered blocks from the k-th even block of the watermarked signal to retrieve <o ostyle="single">s*k(n), transforming <o ostyle="single">s*k(n) into the frequency domain to generate <o ostyle="single">Sk(f), calculating a phase of <o ostyle="single">Sk(f) as <o ostyle="single">phi(f) and a phase of Sk(f) as phi(f), calculating the difference Psi(f) between <o ostyle="single">phi(f) and phi(f), unwrapping Psi(f) to obtain the phase modulation {tilde over (Phi)}k(f), and using a Viterbi search to retrieve the watermark embedded in {tilde over (Phi)}k(f).
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