Technology Research, Based On Digital Watermark Information Hidden

With the great development of multimedia technology and the popularity of Internet, information security issues attract many people's attention more and more. Responding to such application demands, information hiding technology has been developed rapidly in recent years. As a primary branch of information hiding, digital watermarking has become one of the most hot spots in the filed of security.Digital watermarking adds some digital information to the multimedia data and make seldom impact on the seeing and hearing of the original data. Moreover, the digital information can be resumed partly or wholly from the mixing data in order to protect copyright and so forth. In general, digital watermarking should have the characteristic of security, robustness and can't be aware. The algorithm of digital watermarking not only can discern the relevant information of the rightful ownership that embedded in the protection target, but also can draw out it if need be. Watermarking can be used to differentiate whether the target is protected or not, watch the protected data to spread, distinguish between true and false, communicate in secret, hide the signs and control the illegal copy and so on. These important applications are the basic motive force of developing the digital watermarking in fact.Taking digital images as subject investigated, the fundamental and relative processing of information hiding technology have been presented. The meaningful digital watermarking technology as a branch of it has been studied in the thesis.Firstly, the basic concepts and the merits of digital watermarking are expounded. According to the characteristic and design requirements in various applications, the classification, ways of attacks and rating of merits of digital watermarking technology are investigated. Some typical algorithms of digital watermarking are discussed in detail.Secondly, a novel digital watermarking algorithm based on Real Discrete Fourier Transform is proposed in this paper. In order to boost up the safety and the solidity of the watermarking, Arnold iterative transform has been used to disarray the watermark before embedding. Then the disarrayed binary watermark with random sequences has been embedded into the intermediate frequency components of important coefficient in Real Discrete Fourier Transform field. The algorithm both has the merits of low complexity, high capacity, and better invisibility, and is efficient in computation. The experimental results demonstrated that the method cannot be aware commonly and can offer resistance to common attacks such as JPEG compression, noise addition, and so on.Finally, the existing image watermarking algorithms using singular value decomposition (SVD) was simulated and its flaw was indicated. A new image watermarking system based on Real Discrete Fourier Transform (RDFT) and SVD is proposed. This scheme sampled the coefficients from the amplitude of frequency after (RDFT) to recompose as a square matrix. The matrix is partitioned into blocks and performed SVD transformation. The watermarking was embedded into the largest coefficient from each component. The experimental results proved the algorithm is a valid method against many geometrical attacks. The method has the merits of security, robustness and confidentiality.