Digital Watermark Research Based On Wavelet Domain

Nowadays,technology develops rapidly;computer and Internet have become an indispensable elements in people's lives.More and more products exhibit to people in digital form following by the increasingly flinty problems of copyright bother.Digital watermarking technology as an important mean of copyright marking is playing a more and more important role in this field.Digital watermarking is a signal that is embedded into digital multimedia products in perceivable or unperceivable form for protecting copyright,verifying content,or providing other information.The watermark integrated with the host information closely,and hidden in it, which has become an impartible member of the host information,and could survive the manipulations which don't destroy the host's value of use and commerce.Digital watermarking technology relying on its unique advantages can be applied in copyright protection,illegal copy,confidential communications,and many other fields,which has important practical significance and applicable value.In wavelet domain,adaptive digital watermarking technology for image protection is researched in the dissertation.At first the notation,principle, genetic model,basic characteristic,typical algorithms and evaluation of performance are described.Then the theory and application of wavelet transform are introduced.Second,several common algorithms about image watermarking encrypting is introduced and been proved through the experiment.Based on the research and the problems that exist to be considered and solved,two adaptive watermarking algorithms in wavelet domain for images are proposed.They are all about the problem of how to get the best embedding strength of the watermark and embed the watermark adaptively.In the same time,to improve the invisibility and robustness, human visual system is used to select the appropriate position to embed the watermarking signal adaptively.All experiment data is drawn out for the performance analyses.The experimental results show that the imperceptibility and robustness of these methods can be guaranteed.Finally we review entire work.Something need to research in the next step is pointed out.And we suggest the direction for the future research of watermarking.