Research Of Digital Image Watermarking Algorithm Based On Transform Domain

With the rapid growth of internet technologies and extensive use of multimedia data, the enforcement of multimedia copyright protection becomes an important issue. In the situation, digital watermarking is widely studied and used as a new technology for copyright protection and content authentication in recent years. It embeds some secret messages into the multimedia to protect the property or integrality so that digital produces can resist being copied, tampered and so on. Digital image watermarking algorithm is a important part of the investigation hotpots in the digital watermarking technology. Among the various classifications of watermarking, transform domain image watermarking technology is mainly studied in this paper.First, a recapitulative introduction is made in this paper, which includes the basic theoretic knowledge of digital watermarking technology such as background, development situation, main application field, concept, sort, basic principle, characteristics, common attacking methods, assessment programme and so on. Second, several common algorithms about image watermarking encrypting is introduced and been proved through the experiment. Then two kinds of digital watermarking algorithm are proposed. One is a gray-scale blind watermarking algorithm in DCT domain based on chaos permutation, the other is a blind watermarking algorithm in DWT domain based on hyper chaos and human visual system. To improve the security and visual effect, chaos and hyper chaos is used to scramble the watermarking signal. 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. Finally, conclusions about this paper are made and several opinions about the further research is proposed.