Digital Watermarking Algorithm On Discrete Wavelet Transform

Research in the digital watermarking technology is hotspot in the field of information security research, receiving much concern because of its wide application value. This paper study the theory and algorithm in the digital watermarking based on discrete wavelet transform. We do the following work:1. Introduce the basic concepts and research status of the digital watermarking technology. Introduce the basic framework of digital watermarking system. Introduce the characteristics of digital watermarking technology, classification, application, evaluation method, and the typical algorithm briefly.2. Introduce the development of the theories in wavelet analysis, wavelet function, wavelet transform and multiresolution analysis etc.3. Propose a digital watermarking algorithm based on DWT. Scramble the watermark depending on the Arnold mapping. The watermark information is encrypted in pscudo random state. The watermark information is embedded into each frequency component of three levels after wavelet decomposition. The algorithm Strengthen the robustness of the watermark. Experiments show that the algorithm is effective.4. Put forward a watermarking algorithm in color image based on DWT against geometric attacks. The color image can be divided into R, G, B gray images, which is embedded in the B component in spatial domain watermarking, G embedded component frequency domain watermarking, realizes the combination of spatial, frequency domain. Experiments show that this algorithm is robust.5. Proposed a color image digital watermarking algorithm based on DWT and human visual system, using the information of image wavelet transform and human visual system fully concentrated on the watermark embedding strength and direction of controllable superiority strong, the watermark is embedded into the low frequency component of three levels after wavelet decomposition, to achieve a better balance of robustness and transparency the. Experiments show that the algorithm is effective.Finally, the researches work of this thesis are summarized, at the meantime, the existing problems and the direction of further study are also proposed.