Research On Double Watermark Algorithm Based On Transform Domain

With the rapid growth of Internet and multimedia information,all kinds of digitalized products can be transmitted more conveniently and efficiently on the network.At the same time,the security problem of digital media is also following.The problem of piracy and malicious distorting of digital products is facing the severe test.In order to solve the security problem of digital media,digital watermarking technology is born on the occasion.Digital watermarking is an important branch of information hiding.It can embed copyright information into digital carriers,and it will not affect the use value of digital carriers.However,there are many kinds of watermarking algorithms,but most of them are single watermarking algorithms.For example,the robust watermarking algorithm can only protect copyright,and the fragile watermarking algorithm can only detect distorting,with a relatively simple function.In addition,researchers have proposed some dual watermarking algorithms,but there are many shortages in performance.This article focuses on this issue that the traditional watermarking algorithms is not perfect enough to meet the needs of many application scenarios,and the problem that dual watermarking algorithms have poor performance.This article proposes two dual watermarking algorithms based on transform domain.The multifunctional protection of image is realized,and the application scenario of algorithm is enriched.The following is the main work done in this article:(1)Firstly,the background,concept,classification and characteristics of the digital watermarking algorithm are briefly introduced.After that,the research status of single watermarking and dual watermarking algorithm both here and abroad is systematically expounded.Finally,the existing models of single and dual watermarking algorithms are researched and analyzed.(2)Aiming at the problem that the robust watermark has badly anti attack ability and fragile watermark has low tamper detection ability in the dual watermarking system,a dual watermarking algorithm based on Contourlet-DCT-Hessenberg is proposed.In this algorithm,a robust watermark and a fragile watermark are embedded in the image.The robust watermarking algorithm firstly transforms original image by Contourlet,then the obtained low frequency coefficient matrix is partitioned into the DCT domain,the medium and low frequency coefficients of the DCT domain are scanned for matrix recombination,and the recombination matrix is decomposed by Hessenberg decomposition,and the watermark is embedded in the matrix after the decomposition.In order to reduce the impact of fragile watermark on robust watermark,the fragile watermarking algorithm uses zero watermarking algorithm to extract the image feature value as a fragile watermark and save it in the watermark database.The experimental results show that the robust watermark of this algorithm is robust,and the fragile watermark is very sensitive to the image tampering,and the tiny changes in the image can be detected.(3)In the algorithm proposed in(2),the embedded robust watermark is binary watermark,and the binary watermark contains less copyright information and less Anti-attack ability.In addition,fragile watermarking algorithms can only perform tamper detection and cannot tamper with recovery.Based on this,a dual watermarking algorithm based on RDWT-SVD and compressed sensing is proposed.The robust watermarking algorithm embeds a grayscale watermark and improves the ability of copyright protection.The fragile watermarking algorithm selects the compressed sensing measurement as a zero watermark,which not only can tamper detection,but also can perform image recovery after the image is attacked.