Robustness Of Wavelet Domain Watermarking Technology

With the development of computer information technology, the application of computer technology becomes popular in every areas in people's living and production. Simultaneity, people begin to pay more attention to the security of digital productions so that the Digital Watermarking Technology appears along with the computer's development. However, the result of digital image watermarking depends on the complicated internet environment. How to guarantee the qualified Robustness when the digital image watermarking is attacked by the environment becomes the key in current research field. My research in this thesis is just based on the Robustness of Digital Watermarking Technology.The Scrambling Technique is the first step of digital watermarking algorithm. It can improve the Robustness of digital watermarking by using the high efficient Scrambling algorithm; meanwhile the Scrambling algorithm and frequency also can be considered as the key of Digital Watermarking Technology to guarantee its security. Here it propose an image Scrambling algorithm based on the magic square and ranks Scrambling in THE research paper, because it has the absolute advantages comparing with other algorithms due to its less calculation time and better result. And another watermarking algorithm in the wavelet filed also be proposed, which is based on HVS. This algorithm is to embed the watermarking in the special field after wavelet dissolution, which can guarantee the none-visibility; in addition, this algorithm employ a high efficiency which is benefit for the Robustness when it is attacked by compressing and cutting. There is still another watermarking algorithm based on the self-adaptation embedded wavelet field. This algorithm is to divide the wavelet field into several parts. According to their different veins, it prefer to embed the numerical value with the intensity modulus automatically. This algorithm not only guarantees the none-visibility, but also enhances its Robustness, even when the rate of compression of original picture reach to 20％, the watermarking can be still distinguished clearly.This thesis aims to do a further research to the Water Image Technology of wavelet field, and to realize its application through the software emulation. The research focus on the Digital Watermarking Scrambling Algorithm and Digital Watermarking Embedded Algorithm; furthermore, it improve these algorithms on the base of other prevenient research. It is pointed out that the research on the algorithm realized a good Robustness with a qualified result. However, there are still some problems unsolved, such as Digital Watermarking Scrambling Algorithm's Robustness is not satisfactory when it is attacked by compressing, and Digital Watermarking Embedded Algorithm's Robustness is not satisfactory when it is attacked by noise. These problems give us the research direction in the future.