The Research Of Digital Watermarking Based On DWT Domain

With the development of the multimedia and the network technology, the copyright protection of multimedia becomes a focus in the academic. Digital watermarking is an important research area in infomation hiding, which plays an important role in multimedia copyright protection such as digital image, etc.Digital watermarking makes possible to embed a watermark ,such as serials number, text or image etc,to multimedia documents allowing copyright protection, secret communication, document authentication and so on.Watermarking technology in frequency domain is a trend in the future.As a new theory of time-frequency domain, Wavelet Transform is promising. Because of its local characteristic, the watermarking technology based on Wavelet Transform is the most active topic in digital watermarking.This paper considers the static digital image as the main research object. The Main content of this paper is organized as follows.1. Firstly, the background and present situation of digital watermarking is introduced, the purpose and effect of this paper is included in addition. Then, it is chiefly concerned with the basic concepts, characteristics and classification of digital watermarking. With a focus on some classic algorithms in digital watermark is introduced.Afterward performance assessment of digital image watermarking is provided, common ways of digital watermark attack are introduced at last of this part.2. A new algorithm combining the DCT with DWT is brought up . Firstly, the original image is disassembled with wavelet, And carries on the DCT transformation again to its low frequency, watermarking is carries on the middle frequency. Experiments show that the algorithm has a good visual masking Properties and shear, increase noise, compression and other attacks have good robustness, and the blind watermark detection is carried out in this algorithm.3. A quantification algorithm based on Arnold transformation of wavelet domain which is also a blind watermarking algorithm is brought up. With Arnold transformation, the security of watermarking is improved. Watermarking is embedded separately at low frequency and high frequency so as to balance the robustness and visibility. Experiment results show that the generated watermarking withstand under common attacks very well.4. Finally, the full article is summarized. At the same time, the prospect of digital watermark in the next future is forecast.