Research Of Digital Image Watermarking Algorithm For Copyright Protection And Integrity Authentication

With the development of Internet technology,more and more digital images are transmitted through the Internet,which causes images to face the problems of copyright protection and integrity authentication.At present,image ownership verification can be realized by robust watermark,and image tampering detection can be realized by fragile watermark.However,image copyright protection and integrity authentication cannot be satisfied by the single watermark of robust watermark or fragile watermark.Therefore,the focus of this thesis is to realize copyright protection and integrity authentication of color images by combining the different characteristics of robust watermarking and fragile watermarking algorithms.An adaptive robust watermarking algorithm Based on Shearlets’ capture directional features is proposed.The discrete wavelet transform(DWT)is unable to represent the directional features of an image.Similarly,a fixed embedding strength is not able to establish an ideal balance between imperceptibility and robustness of a watermarked image.In this algorithm,we improve the watermarking algorithm in the domain of DWT using non-subsampled shearlet transform(NSST).The improvement is made in terms of coping with anti-geometric attacks.The embedding strength is optimized by artificial bee colony(ABC)to achieve higher robustness under the premise of satisfying imperceptibility.The principle components(PC)of the watermark are embedded into the host image to overcome the false positive problem.A fragile watermark image integrity authentication algorithm against complex attacks is also proposed,in order to solve the problem that the localization accuracy and anti-complex attacks of fragile watermarking in image tamper detection could not be satisfied simultaneously.The fragile watermark was embedded into the color image’s R,G and B channels to detect any channel tampering.In order to improve the localization accuracy,2 × 2image blocks were divided.Block authentication and group authentication were used to detect the image tampering of complex attacks to improve the anti-complex attacks ability of the algorithmFinally,the robust watermark and the fragile watermark are embedded into the image sequentially,the robust watermark is used to protect the copyright of the image with strong resistance to multiple attacks,and the fragile watermark is used to authenticate the integrity of the image with the detection ability of image tampering.The experimental results show that the proposed algorithm has better imperceptibility.Robust watermarking algorithm has strong robustness against multi-attacks,especially those of high intensity.Fragile watermarking algorithm has higher localization accuracy for image tampering under common attacks,complex attacks and multi attacks.The two watermarks are embedded into the color image successively in the case where the watermarks performance is not affect,the copyright protection and integrity authentication of the image is realized.