Multiple Digital Watermarking Technology Research And Implementation

With the rapid development of multimedia technology and Internet, the acquirement, exchanging and transmission of multimedia imformation have become a simple and rapid process. As the multimedia imformation becomes easier to acquire, it is also easier to suffer the attack from illegal copy, forgery, tamper and tort. Digital watermarking technique is just proposed to solve those problems. As the new imformation secutity technonoly, digital watermarking has provided an effetive solution to the copyright protection and intergrity protection of digital works.Nowdays, many watermarking algorithms just meet part of digital product security demand. As a result, this paper chooses discrete wavelet transform and chaos theory as theoretical basis, aims at the detail application demand for digital works security. The main points are as following:1,Nowadays most of watermarking algorithms can't achieve copyright protection and content authentication of images all together, therefore this paper designs a new kind of multi-watermarking which combines robust and fragile watermarkings. In the design of robust watermarking, classify the block of low-frequency wavelet coefficients according to the characteristic of the human visual system, then choose different embedding intensity factors according to the class of blocks and self-adaptively embed watermarking by the method of block-mean quantization, improve the robustness of watermarking algorithm; in the design of fragile watermarking, produce the authentic information of image blocks by Logistic chaos mapping, embed authentic information into LSB of image blocks according to the tactic of improved cycle block correlation, finally chaos-scramble the LSB of image blocks. Experimental results show the multi-watermarking algorithm can achieve the aim of copyright protection and content authentication, resist the IBM attack well.2,Synthesize the programming advantages of Matlab and C++, design and realize an extendable digital image copyright protection system by making the use of mixed programming. This system has self-contained functions and satisfies users'multi-requirement, itself is extendable,which is the characteristic of this system. Moreover.Besides, this system increases the module of capability test, which includes some common watermarking algorithm indexes and attacking methods, provides a nicer experimental platform. This system has good utility value.