Research Of Image Content Authentication Algorithm Based On Digital Watermarking

With the rapid development of computer network and multimedia processingtechnologies,we can create,store,edit and spread digital multimedia information more andmore easily.However,The development of technology has also brought a series of informationsecurity issues.For example,multimedia information can be tampered easily,causing badconsequence in the process of transmission.Therefore,how to protect the factuality andintegrity of digital multimedia information has become the urgent issue to solve at present.Based on digital watermarking theories,the problem of image content authenticationbased on digital watermarking has been studied in this thesis.First of all,the fundamentaltheory of digital watermarking,including the concept, principles,characteristics,classificationand its application is summarized and explained;And then,the technology of image contentauthentication and its evaluation method are introduced,a series of problems in the process ofimage content authentication and its future development are analyzed,all of these lay thefoundation for further study on the specific algorithm.Secondly,On the basis of introducing contourlet transformation,an image contentauthentication algorithm used self-embedded watermarking is proposed,the algorithm extractsthe feature information of image by singular value decomposition method to generate binaryimage as watermarking.And then,the watermarking is embedded into the contourlet field ofimage by quantitative method.Experimental results demonstrate that the algorithm is providedwith good transparency,security and practicality,is robust to conventional operation(JPEGcompression,superposition of noise and filtering)and can achieve tamper detection andlocalization to malicious operations.Thirdly, An image authentication algorithm with discrimination of tampers onwatermarking or image content is proposed. At first,the recovery watermark is generated fromthe low frequency coefficients after the contourlet transformation,and is embedded into themiddle frequency subbands by quantization of parity mode.After that,the authenticationwatermarking is embedded into the low frequency subband.The simulation experimentdemonstrates that the algorithm can distinguish the type of tampering. As to the tampering ofimage content, the algorithm can achieve the tampering detection, localization, and restore thetampered content conditionally. At last,the contents of this thesis is summarized and the aspects to research in the futureis pointed out.