Digital Watermarking Algorithm For Binary Image In DCT Domain Based On Chaotic And Scrambling Encryption

The copyright protection of digital works becomes more and more important with the development of multimedia technique and computer network. As a new method of copyright protection, digital watermark is attracted more and more attention of researchers and users with lots of achievements. Although there are many researches focus on static image, they are not mature enough, the invisibility and robust can't be satisfied at the same time.The thesis is mainly focus on the digital watermark of binary image with the following study:1. Analysis the basic theory of digital watermark technology, and also the general principal and module. Make a detail introduction for the evaluation about the performance of watermark image, attack analysis and the relevant detect methods.2. A double encryption method for the original image is put forwards based on the comparison of classic watermark algorithm, which encrypted with the Logistic chaotic sequence, then proceeded with Arnold cat position scrambling transformation, to make the watermark information safer.3. Improve the block classify method based on the comparisons of typical algorithms, embedding the watermark weights with different strength into the middle and low frequency coefficients of DCT domain adaptively according to the classification, to make the embedded image with very good invisibility.Though the experiments of attacking with Gaussian noise, salt & pepper noise, mean value filleting, cropping and JPEG compression, it indicates that this algorithm can make sure of the security of watermark itself, with excellent robust and invisibility, and also make the double guarantee of the protected digital work.