The Research And Applications Of Robust Digital Watermarking And Fragile Watermarking

With the rapid development of internet and multimedia technique, the multi-media data is becoming the important source that the people obtain information gradually, and it constitutes an important part of people's live because of its convenience and speediness. The exchange of the multi-media information has come to an unprecedented depth and wide degrees. The forms of multi-media data release are much abundant, but there are many obvious problems: it is much easier to infringe copyright; it is more convenient to sophisticate etc. As a consequence, how to protect the security of multi-media information turns into a popular topic all over the world.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 and it is researched and applied extensively because of its characteristics that are more excellent than digital encryption. 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.This paper discussed and researched thoroughly in the combination between image waterworks and other watermark based on summarizing the background and the theories frame of the digital watermark technical development. It takes the digital image of the static as an example, the main work contain followings:Firstly, an important content of the digital watermark technique research is the research and design of the robust watermark. This paper advances two robust watermark arithmetic base on frequency field from different particular emphasis, and stress to analyze the present conditions research of the robust watermark and fragile watermark.Secondly, pass to make use of to divide the DCT technique, adopt the Chaotic Encryption to do the pretreatment of the digital watermark image, raise the ability of resist cutting, choice the right block according to the human visual system, then imbed the watermark into the better block of the coefficient of intermediate frequency by the period characteristic of remainder, carrying out the blind detection while examine watermark. After the experimentation, the arithmetic has the stronger robust to the attacks of shear , filter and the JPEG compresses etc, but it needs the improvement on the attacks of revolve transformation and the strong yawp.Finally, it introduced the latest digital watermark technique--zero watermarks, andconcludes the stronger characteristic, which carries out the combining robust with frangibility, and which is other multi-function digital watermarks technique can't complete independently. It advances the zero watermark arithmetic, which is based on EZW and SVD and carrying out the combining robust with frangibility. This method has the characteristic which is simple and low complication, and has the robust to familiar image processing. The experimentation result indicate that method not only have the robust, but also can attain the orientation ability of fragile watermark, then carried out the robust and frangibility at the same time.