Digital Image Watermark Technology Research Based On DCT Domain

With the rapid development of digital technology and Internet, digital media can be copied and spread with low-cost and high-speed, which made it convenient for both authors and users, and challenged the protection of media copyright as well. One of the hottest topics is that how to provide technical protection to digital media according to their characteristics. The digital watermark technology is one of the methods. Digital watermarking technology is an immature field, there are many issues that must be resolved, such as the encryption is not enough and the robustness is not strong for Watermark system. Several existing programs is still not perfect, the digital watermarking theory is still lack.This paper discussed digital watermarking technology and its application from the viewpoint of practical engineering, and focused on DCT domain digital image watermarking technology. In this paper, the current typical DCT domain of digital watermarking were analyzed and summarized. Based on the previous work, a dual encryption algorithm was proposed by combination of Arnold transformation and logistic chaotic scrambling, thus strengthened the security of watermark information. In the stage of watermarking embed, a new image-adaptive watermarking algorithm in DCT domain was proposed, and binary watermarking was embedded, which can improve the secrecy and robustness of watermarking remarkably.In order to test the robustness and the imperceptibility of the algorithm, a large number of simulation experiments have been done. For example, image cropping, JEPG compression; Gaussian noise, median filtering and cutting, and the experimental results were given. The results indicate that the watermark generated with this algorithm is both invisible and robust against the common signal processing attacks. And the algorithms can adapt to various forms of meaningful grayscale images embedding. The security and robustness of Watermarking system were solved effectively.