Studied Digital Watermarking Method Based On Chaotic Systems With Frequency Hopping

The rapid growth of multimedia manipulation tools and network access leads to convenience of multimedia information processing, distribution and storage. At the same time, multimedia information security problems including copyrights piracy emerge as side effects of the popularity of digital representation and distribution over network. Digital watermarking has been demonstrated to be very effective in identifying the source, creator, owner, distributor, authorized consumer, or integrity of a media document (usually an image). In this dissertation, several important problems about digital watermarking are studied. Novel algorithms are proposed and the experimental results are given.The background and overview of digital watermarking are introduced in chapter 1 and chapter 2.To solve the problem of watermark encryption, a novel permutation operator is proposed, based on which the permutation scheme and the substitution scheme for watermark encryption are designed; Encryption algorithms in spatial domain and transform domain are proposed. The ciphered image can be JPEG compressed before it is transmitted, and low-distortion plain image can be obtained after decrypting the compressed encryption image. Experimental results and analysis demonstrate that the algorithms are of favorable security and efficiency.A novel digital watermarking scheme based on synthesis and separation method of direct and alternating signal is proposed in chapter 4. A direct signal is founded in host image in DCT domain, and the modulated watermark is regarded as alternating signal, so watermark embedding and extracting are similar with direct and alternating signal synthesizing and separating. Experimental results show that embedded watermark has a certain capacity and robustness.A virtual channel technique, which is based on frequency hopping technique, is proposed in chapter 5. A novel blind watermarking algorithm based on virtual channel technique is designed, by which a gray-scale image is embedded into host...