Research On Digital Watermarking Of Images

Along with the fast development of internet and multimedia, the problem about how to protect the information of multimedia and digital products has already been an important issue cared by all the countries in the world. Digital watermarking occurred in such a background, which can make up the shortcomings of traditional methods of information cryptology, and has widely used in the fields of authentication, prevent-counterfeiting, prevent-tampering, safety and security of data. Nowadays the digital watermarking is developing quite quickly, and a lot of achievements have been obtained.The paper focuses on the theory and methods of digital watermark in static image. The main work having been done are as follows:The basic conception of information hiding and digital watermark and the framework of digital watermark system are discussed, which include watermark production, embedding, detection, extraction and attacks being encountered. The classification and features of digital watermark technology, representative algorithms and applications are introduced.According to the characteristics of human visual system, an algorithm of embedding watermark is discussed in detail, which is based on both DWT and DCT. And some experiment results are given, which validated that the algorithm is effective.According to the apperceive features of human vision, an algorithm of watermark is proposed, which uses the green weight of a color image. The experiment results show that the algorithm can well keep the original image quality and has better robust.