The Study Of Color Image Digital Watermarking System Based On Wavelet Transform

Facing the human society entered the digital age,the digital productions'copyrights and the safe transmission of digital information are the problems which need to resolve imminently, and digital watermarking technology will be effective in resolving the problems and it will be a potential technology. Because wavelet transform is according to the transformation mechanism of human visual system, and it is adopted by new generation image compression standard JPEG2000 and video compression standard MPEG-4, discrete wavelet transform is selected to embed the watermark in the subject.The main purpose of this paper is to study the digital watermarking algorithm based on still color image, watermark images are binary image and color image. The color image is mostly described by RGB format, but this format have some disadvantages, such as excessive redundant information, strong correlation between red-green-blue three primary colors, great operation, and so on. And it is unsuitable to human visual system; as a result YIQ color space is adopted to embed the watermark in the paper. First of all, the principles and general elements of digital watermark system are introduced briefly, and the characteristics, classifications, typical algorithms, attacks and application areas are also explained. Then the basic theories of wavelet transform are discussed in detail. The theories include the conception of wavelet transform, multi-resolution analysis and watermark embedded position. Then the algorithm that the color watermark is embedded into original color image using discrete wavelet transform is analyzed. Then 1-D and 2-D Logistic chaos are introduced simply. And the algorithm that the color watermark scrambled encryption by 2-D Logistic chaos is embedded into original color image using discrete wavelet transform is analyzed. And then, the common color space models and the transformation formulas are described, and gave the Just Noticeable Distortion (JND) in wavelet domain by using human visual system(HVS). And the algorithm that binary watermark scrambled encryption by 1-D Logistic chaos is embedded into original color image through calculating the value of JND by using human visual system is analyzed. And concretely gave out the model, program flow chart and the experimental results of every algorithm. The experiment results show that the above algorithms all have good transparency, and they are all robust to the usual attacks. Finally, the amount of the subject is given, and the directions of research work in the future are offered.