Design And Optimization Of Digital Image Watermarking Algorithm

The explosive growth of Internet usage has made information dissemination easier,leading to serious copyright infringement issues,such as unauthorized copying,distribution and modification of digital works.In order to improve the effective utilization of network information,the copyright protection is becoming particularly important.As one of widely used protection technologies,watermarking has been applied to many fields of multimedia copyright protection.Watermarking is a common information embedding technique to protect image,video and audio information.It embeds key information into the data that needs to be protected by invisible modifications.In the image watermarking scheme,the main concerns are security,invisibility and robustness.The chaotic system can be used to guarantee the security of the watermark scheme because of its good randomness,unpredictability and initial sensitivity.The invisibility is mainly reflected in the fact that the watermarked information has small difference from the original one in visual aspect,and the robustness is an indicator that the quality of the the extracted watermark after being subjected to various types of attacks in the watermarking scheme.Among the above three factors,it should be noted that improving the security performance under various types of attacks becomes the key to improving the robustness,especially the cropping,rotation and color correction attacks.At the same time,how to balance the contradictory indicators of invisibility and robustness becomes a difficult point in the image watermarking design.In addition,when the size of the watermark changes,it is necessary to consider the adaptive problem of the watermarking scheme.Therefore,how to design a safe watermarking scheme that adapts to the high invisibility and strong robustness with multiple sizes of watermarks has become the focus of this paper.The main work of this paper is reflected in the following four aspects:1.The research background of the subject is introduced,including the current watermarking scheme overview and existing problems,and then the innovation of this paper is given.Then the factors and evaluation basis that the watermarking scheme which need to be considered are described,and the current research status of watermarking schemes is summed up.Finally,several shortcomings in digital image watermarking are analyzed,and the corresponding solutions are given.2.Aiming at the false positive problem needed to be in the security performance in image watermaking schemes,two watermarking schemes based on chaos and transform domains are proposed.The first one is based on coupled tent-sine mapping watermarking scheme.The chaotic system protects both host and watermark images.The embedded position is found by the chaotic map at the same time,and the experimental results show that the robustness is improved and the invisibility meets the requirement.The second is a watermarking scheme based on Hessenberg decomposition and singular value decomposition.The chaotic system based on Logistic mapping is used in solving the false positive problem,and the proposed scheme solves the problem of multisize watermarking at the same time.The robustness and invisibility of the proposed watermarking have good performance.3.In order to improve the invisibility and the robustness against cropping and rotation attacks of the above schemes,a watermarking scheme based on singular value decomposition and wavelet transform is proposed.Firstly,the host image and the watermark image are encrypted to avoid the false positive problem,and the security is improved.Secondly,the proposed searching rule is used to improve the embedded components,thereby improving the invisibility and robustness.The experimental results show that the algorithm implements a high-invisible and robust security watermarking scheme,and solves the robustness of cropping,rotation and color correction attacks,and has strong robustness performance against other attacks as well.4.A Hessenberg-based blind watermarking scheme is designed.According to the proposed embedding rules,the embedded components are improved,which improves the invisibility and robustness of the algorithm.The experimental results show that the proposed algorithm is robust to several attacks and especially has strong performance improvement for cropping,rotation and gamma correction attacks.