Research On Digital Image Watermarking Algorithm Based Classic Transform Domain

With the rapid development and popularization of the Internet in recent years, the dissemination and access of digital products has become increasingly simple, which led to a growing digital copyright issue. Because digital watermarking is one of the effective means for copyright protection, it has gradually become a hot research field of information security. The main performance requirements of the digital image watermark are robustness and invisibility. The robustness refers to the watermark information’s resistance to various image attacks. The invisibility is used to evaluate the visual effects of the carrier image after the watermark information embedding operation. According to the different positions of the image where the watermark is embedded, digital image watermarking algorithm can be divided into two categories:space and transform domain algorithms. The space algorithm is simple and has large payload, but it cannot guarantee the robustness. The transform domain algorithms can distribute the energy of watermark to all the pixels of the entire image, and it is indiscernible to the human eyes and has better robustness. Therefore, the digital image watermarking algorithms based on the transform domain have a better application prospect and research value.This paper is started by describing the research background, research significance and research actuality of the digital watermark. Secondly, this paper makes an overview presentation of digital watermark technology from the working principle, classification, types of attack, performances, algorithm evaluation and usages. Thirdly, this paper studies the application of the discrete cosine transform and Arnold transform in digital image watermark technology. Then this paper simulates and analyses a digital image watermark algorithm using a combination of DCT and Arnold transform. For the defects existing in this algorithm, an adaptive improvement algorithm is proposed, and the simulation results show that the improved scheme is simple and effective. Fourthly, this paper studies the combining application of digital image watermark technology by simulating and analyzing a digital image watermark algorithm with combination of DCT and DWT. Based on the basic idea of this algorithm, a new digital image watermarking algorithm with DCT and DWT is proposed, the simulation results show that the performance of new algorithm is better. Finally, the thesis work is summarized and looks into the future of next phase of work.