Research Of Dual Watermarking Technology For Digital Image Based On Transform Domain

With the development of varieties of hardware technology and software technology, mankind has already entered the digital era. We can transmit the digital information around the world with the aid of electronic devices conveniently. While enjoying quick service, people are increasingly concern about the security of the pattern digital information transferred. Under the situation, a new type of digital information security technology which is digital watermark that coming into our view and it can be rapidly developed. It is because the in-depth study of digital watermark technology, it can effectively promote the research study of covert communications and copyright protection for digital works.Firstly, this paper started with the research status and prospects of digital watermarking, it systematically expounded the basic concepts of digital watermarking, principles, framework, basic features, common attack methods towards it and exclusive performance evaluation. At the same time, this paper analyzed the typical algorithm for digital watermark in the spatial domain and transform domain, then compared all the algorithms mentioned above, draw a conclusion that watermarking algorithm based on discrete wavelet are superior to the other algorithms. In this paper, it also introduced a series of detailed knowledge about the wavelet analysis theory, Arnold scrambling, the human visual system, color space etc, which is closely related to the wavelet analysis theory.Secondly, this paper improved two digital watermarking algorithms to reference [20] and reference [29]. Experimental results show that the improved algorithm can completely meet the requirements of concealment as a watermarking algorithm, and they also demonstrate better robustness contrast to the unimproved algorithm.Finally, this paper designed a dual watermarking algorithm based on the two improved watermarking algorithm above, that is embed the binary watermark and color watermark to the color vector images. In the combined algorithm, binary watermark is to identify the copyright of digital works, and the color watermark is to confirm it. They are both separate and related with each other. For authenticating the dual watermarking algorithm, except subjective visual assessment, it also uses a numerical objective evaluation to do quantitative analysis in this paper. All design were performed on MATLAB simulation software, experiment results have showed that the dual watermarking algorithm mentioned in the paper combines good robustness and good concealment.