| With the great development and wide use of computer, Internet, and multimedia, the communication information security, copyright protection and proofing of digital media are becoming a very important problem that needs to be solved urgently in digital world. So Digital Watermarking emerges in response to the needs of the times. The thesis focuses on the applications of Digital Watermarking in digital image.First, the current development status, conception, characteristics, sorts, basic theory models, typical algorithm and standards of digital watermark system capability are introduced.Second, the conception and characteristics of chaos kinetics, some sorts of typical chaotic systems, the methods of how to make chaotic sequence are introduced.Third, the digital image watermark algorithm based on DCT and DWT domain is systematically analyzed and compared. With the groundwork of literature, we add chaos theory into digital watermark algorithm, then we use it to encrypt binary mark image, and embed the watermark into digital image both in DCT and DWT domain. Combining the strengths of DCT and DWT, a sort of digital image watermarking based on chaos theory in both DCT and DWT is realized.Then, the color image digital watermarking technology is researched. The basic knowledge of color and color space is introduced. In order to improve the security of watermark system, the basic theory of the spatiotemporal chaos is introduced, then the spatiotemporal chaos is used to encrypt binary watermark. By means of the irrelative characteristic between Y and Cb,Cr components in YCbCr color apace, and the Y part of color image in DWT is dealt with, a sort of color image digital watermarking based on the spatiotemporal chaos is realized. At the same tome, in order to represent the characteristics of color image better, a sort of color image adaptive digital watermarking algorithm is put forward, and the two algorithms are compared.Finally, the thesis is summed up, and the future work is prospected. |
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