The Research Of Video Watermark Algorithm For Resisting Collusion Attacks

With the development of Internet and wireless, it is easier for people to obtain real-time image and video over networks nowadays. However, content owners also see a high risk of lawless copies and piracy. So suddenly people become interesting in copyright protection content. There are cryptography and watermarking for copyright protection of content. As the earliest technique for copyright protection of digital production, cryptography has received systemic research. But once decrypted, the content has no further protection, while being accompanied by digital watermarking for the whole lifecycle, which is a superiority of this new copyright protection content technique. As a new and effective approach to solve the copyright protection problem, digital watermarking has become a popular research area within the field of information processing and security. By embedding all the copyright information such as number, word and icon into the data of multimedia using watermark technique, we can protect copyright, communicate secretly and inspect the truth of digital products. Among all kinds of digital watermarking techniques, researchers have paid more attention to video watermarking technique due to its high research value and potential market demand. But currently video watermarking techniques lag far behind image watermarking techniques for the difficulty of design and implementation of the algorithms and the turning up of some special attacks against video watermarking techniques(for example collusion attack) which raises difficulties and complexities for digital image watermarking. This thesis focuses on video watermarking algorithms for resisting collusion attacks. The main research work and contribution of this thesis are as follows:(1) This thesis systematically summarizes the characteristics and the application of video watermarking, and focuses on the research status of video watermarking algorithm and principles. Several traditional video watermarking algorithms are studied, and the analysis is given in detail. The frame of video watermarking system and standard of the performance of video watermark are summarized.(2) This thesis introduces a new anti-linear collusion attacks video watermarking algorithm that is based on content according to the relationship between the feature of image and the sub-frame DCT coefficients. This algorithm breaks the regularity of watermark embedding, thus effectively resisting collusion attacks. Meanwhile, through computing the JND value of the sub-frame, it can dynamically adjust the intensity of spread spectrum watermark while embedding. Experimental results have shown that the proposed strategy can effectively resist two types of linear collusion attacks, while still being strongly robust, stability and imperceptible.(3) This thesis introduces an anti-collusion attacks algorithm that is based on video frame statistical regulation according to the statistical invisibility of video frame .In this algorithm, we utilize the feature of two kinds of collusion attacks, while incorporating the thinking of statistical invisibility watermark to design two kinds watermark algorithm. The watermark algorithm delicately incorporates the features of watermark algorithms basing on spread spectrum and quantization and makes sure that the embedded watermark lives up to statistical invisibility and can resist collusion attack. Experimental results have shown that the given algorithm is strongly robust against the two types of collusion attacks.