Research On Image Digital Watermark

With the growth of network and multimedia technology, the copyright protection of multimedia becomes more and more important. Watermark technology, as a main method of providing copyright protection, has been widely studied and applied. In the paper, we mostly discuss the principle of digital watwemarking algorithm and the analysis of its security and robustness. The main reseach work and contributions of the dissertation rea as follow:1. To the problem of copyright protection, we propose an asymmetric watermarking method based feature space decomposing. Passing feature space decomposing of digital image, we obtain that the robustness of the approach lies in hiding a watermark in the subspace that is least susceptible to potential modification. In the same time, because we use different matrix operation to embed (secret key) and extract (public key) a watermark, we are able to release all information for the public., except the secret key. Through analysis and constraint the conditions, we can obtain a high detection probability and security, a low false alarm probability. The robustness of our method is demonstrated by various attacks through computer simulation.2. We obtain that the robustness of the approach lies in hiding a watermark in the subspace that is least susceptible to potential modification. And through analysis and constraint the conditions, we can obtain a high detection probability and security, a low false alarm probability. In the same time, because we use different matrix operation to embed (secret key) and extract (public key) a watermark, we are able to release all information for the public, except the secret key. Our method can extract the embedded watermark without reference image. The robustness of our method is demonstrated by various attacks through computer simulation 3. To the security problem of digital watermarking based on the singular value...