Research Of Image Watermarking Algorithm Based On Neural Network

The digital watermarking technology, a branch of the information hiding, belongs to information security field. As one aspect of the digital watermarking technology research, the digital image watermarking is of high research value and application prospects, and now,it is becoming a hot academic research.Firstly, the dissertation presents the basic concepts and the related knowleges of the digital watermarking technology, especially placinging an emphasis on each image watermarking algorithm. And a conclusion is drawn: the spatial domain watermarking algorithm has better robustness, but inferior in image quality .and the transform domain watermaking algorithm improves the disadvantage. However, the desired results are still not attained. Therefore,It has become a trend to combine some advanced technologies in other field with digital watermarking technology. Secondly, Based on the works mentioned, it presents two image watermarking algorithms based on NNT:1. NNT extract based relationship among the adjacent pixels watermarking algorithm. In an image, there exists high correlation among the adjacent pixels. Therefore, by subsampling the original image with 3×3 block, N subimages that have high correlation can be attained. And then, Since the relationship among the adjacent pixels belongs to a complex nonlinear relationship, there also exists the relationship among the coefficients on the corresponding position of every coefficient set. Due to the nonlinear regression abilty of NNT, NNT is used to model the relationship to a extract the watermark.2. NNT extract based relationship among the value of the lower watermarking Coefficient and in DCT block. In Supposed algthom We utilized NNT simulate relationship among the value of the lower Coefficient of DCT block .Applying the NNT to model the relationship between it and its neighbors, a binary sequece is attained. It was can be generated a meaningful watermark. The experimental results show the algorithms have excellect performance against various attacks.