Study Of Complex Adaptive Blind Watermarking Technology

With the development of the network and the multimedia technology, the application of the digital product is wider. The security of multimedia is becoming an urgent problem. Of all the solutions to the protection of the digital works' copyright, the watermarking technology is more effective one. Therefore, the study of this technology becomes a focus in the academic world.Digital watermark is a method that it is imperceptibly embedded an identification code into multimedia for the purpose of proving ownership. As one part of multimedia the watermark is strong enough to keep the values for using or business after some destroys.In this paper, first the background and the actuality of digital watermarking are introduced. Then the digital watermarking about the definition, framework, application, typical algorithm, attack analysis and future research directions are dissertated. At last the theory of lifting wavelet transform, image replacement and chaos are introduced.Based on the analysis of the research in the existence of the multi-watermarking algorithm, a new composite adaptive blind watermarking algorithm is proposed. In the algorithm, the robust watermark is embedded in selected sub-band of the frequency domain according to neighboring symbol's mean value and odd-even judgment rule. Then the watermarked image is partitioned into small pieces. Let the grayscale average value of small pieces become the initial values of the chaotic mapping. At last the fragile watermark obtained by iterating several times of the chaotic mapping is embedded into the LSB plane of the watermarked image. The algorithm proposed in this paper can produce the watermarked image which has high fidelity at the expense of the less robust. At the same time, the orders for dual protection are realized. Experimental results and attack analysis show that the method is robust against normal image processing such as JPEG loss compression, filtering, additive noise, and cropping attacks. Meanwhile, besides telling you whether an image has been tampered, the fragile watermark can reflect the distortion status truly and intuitively.