Dynamic multi-watermarking and detecting in DWT domain

Dynamic multi-watermarking embeds watermarks into the same region of a cover imperceptibly by simultaneously using different embedding rules. It is regarded as a solution to protect the cover’s copyright or track illegal distributors. Till now, few works have been done on multi-watermarking, especially dynamic multi-watermarking. In this paper, a novel dynamic multi-watermarking rule is proposed, which embeds different watermarks into DWT coefficients controlled by two secret keys, i.e., the sign control key and the factor control key. Two types of the corresponding dynamic multi-watermarking detectors, i.e., optimum and locally optimum, are derived based on the generalized Gaussian distribution and NP criterion. The robustness of the proposed scheme is analyzed using the optimal Lagrange algorithm, which aims to obtain optimal embedding strength factors. Experimental results verify the prominence of the proposed scheme and the validity of theoretical analysis.