The Study Of Image Authentication Technology Based On The Invertible Watermark

With the rapid development of information technology, people's life has beenchanged. The more advanced information technology develop, the more convenientlypeople can control their life. While the free transmitting of multimedia data in the opennetwork brings lots of conveniences, the illegal use of information and network bringsserious information safety questions day by day.Digital image is the main composition of multimedia data. For it is easy to becoped and to be tampered, the reality authentication of digital image has been anincreasing urgent issue in sensitive area such as medicine, law and army. By reason offragile watermark's unique advantage, it provides an efficient method to the issue. Thereis natural connection between digital watermark and chaos encryption. This dissertationmainly studied invertible fragile watermark technology and its application in imageintegrated authentication.We first give a brief overview of wavelet transform. It consists of the definitions ofCWT and DWT, the multiresolution of wavelet transform, Mallat algorithm and thechoice of wavelet base in digital watermark. In the next, we studied the general theoryand general models of the digital watermark, pointed out its main foreground ofapplication. Fragile digital watermark techniques in image authentication were analyzedin detail. Main attack methods of the digital watermark also are summarized. In addition,we studied related techniques including Human Visual System and digital chaos system.In the next,On the basis of the analysis and research of the existing fragile watermarka1gorithm, this dissertation put forward an invertible fragile watermark algorithm forimage integrated authentication, which is based on directional wavelet transform andmulti-chaos map sequence. By getting image's features with directional wavelettransform, the algorithm realizes digital watermark self-embedding. It can stand againstthe collage attack by encrypting watermark with multi-chaos sequence. The algorithm isable to realize integrated authentication and tampering location. The experiment verifiesthe algorithm's efficiency. In addition, if the image hasn't been distorted, the watermarkcan be wiped off and the original image can be acquired.