The Research Of The Digital Image Watermarking Technology Based On DCT

With the rapid development of Internet and multimedia technique, digital media including digital image has been widespread used, the multimedia data is becoming the important source that the people obtain information gradually, but the problems of information security of digital media occur. Digital image can be found on web everywhere, copying,editing and diffusing image, infringe copyright become a very easy job in information era; Digital image processing technology has been mature, it is more convenient to forge and sophisticate. Copyright protection and content authentication of image trouble people increasingly and need to solve those problems urgently. In this situation digital watermarking technology emerge. It has been a hot issue in information security.This paper mainly discusses the watermark technique applied in information security concerning digital image. The watermark technique is one of the important branches in digital information security which servers to protect copyright. It is used to confirm the ownership or integrities of the data by the watermark with secret information, which is imbed into the original data, to boycott the pirate edition or distort to the digital work.In this dissertation, it is systemically analyzed about the application of watermarking in still images. First, the current development status, conception, characteristics, sorts, typical algorithm, application area and standards of digital watermark system capability are basic theory introduced.Secondly, for the traditional watermarking which can do it is somewhat complicated, make use of the DCT technique, adopt the eigenvector to do the pretreatment of the digital watermark image, watermarking based on the DCT and eigenvector is proposed. The algorithm picks out part of the overall DCT coefficients combines with the"Eigenvector Sign Sequence", produce a key to prove watermarking. Experimental results show that the proposed method is has the stronger robust to the attacks of shear,filter and the JPEG compresses etc .Then it focuses on the least significant bit technology as well as Arnold which is the chaotic method. Arnold chaotic method enables to have the significance image watermark uniform distribute and disorder to the image, and increased the system security. Combining the strengths of discrete cosine transform and least significant bit, and embed the watermark into digital image both in DCT and LSB domain. A sort of digital image watermarking based on Arnold chaotic method in both DCT and LSB is realized. After the experimentation, the arithmetic has the stronger robust.Finally, the thesis is summed up, and the future work is prospected.