The Research And Application Of Digital Watermarking Technology 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.Digital watermarking is viewed as an effective way for intellectual property right protection of multimedia data.At first the thesis introduced the digital watermark history,the domestic and foreign research results as well as the present situation.Then analyzed some existence questions of present digital watermark technology, drew out the selected topic's significance and the prime task.Afterwards introduced the technologies of digital image watermark and explain the essence of digital image.In Chapter 3,the thesis introduced the different methods of digital image watermark in the Spatial Domain and the Transform Domain. Compared these methods by the analysis,clarified weaknesses of the Spatial Domain digital image watermark and the good point of the Transform Domain.In the Transform Domain mainly analyzed the discrete cosine transform and discrete wavelet transform.Then obtained that discrete wavelet transform(DWT) algorithm's multi-resolution has the better quality through the two algorithms with the human eye vision effect different union degree comparison,.In Chapter 4,the thesis emphatically introduced the discrete wavelet transform principle as well as Arnold which is the chaotic method. Arnold chaotic method enables to have the significance image watermark uniform distribute to reduce the image coupling,and increased the system security. The Arnold inverse transformation method not to use its periodicity,but used one kind of inverse transformation solution method which proved by the theory, and enhanced the system efficiency.In Chapter 5,the thesis introduced DWT watermark system algorithm.The algorithm operated in frequency domain,embeded picture which had copyright. A blind watermark retrieval technique that can detect the embedded watermark without the original image,so that the proposed techniques represented a major improvements to those relying on the comparison between the watermarked and original image,which is not practical for a huge image database.All process,including watermark embedding,extracting,verification and analyzing of the embedding parameter,were simulated in MATLAB environments.The result of experiment explained that the embedded watermark was robust against various signal processing and compression attacks.Finally the thesis summarized the experimental result,and pointed out the good and bad points of present paper and the next research direction.