Research On Anti-print-scan Digital Watermarking Algorithm Based On Contourlet Transform

With the great development of information technology in recent years, people's work and life becoming more and more convenient, but the pirated products emerge one after another. Therefore, people are eager to protect the copyright of the printedking and the low operation speed. To solve these problems, the paper proposes the research on products. How to improve the forgery prevention technology is becoming an urgent problem, especially the anti-print-scan algorithm research on digital images. Now, the algorithm using digital watermarking is better than the traditional forgery prevention technology. However, there are still some problems, such as the reconstruction quality of image, the quantity of the watermar anti-print-scan algorithm based on Contourlet transform. The algorithm includes the following several aspects:Firstly, this paper researches the work processes of the printer and scanner. By analyzing the influence in the processes, we summaries lots of attacks and distortion.Secondly, based on the first-generation wavelet, we apply the second-generation wavelet in the anti-print-scan algorithm. In view of the boundary of the image is damaged badly, we choose the Contourlet transform, which is one kind of the second-generation wavelets transformation. It works better than the first-generation wavelet when processing the image with complex texture. In addition, we can find the special relationship between the Contourlet coefficients. The important function can be constructed using these coefficients.Thirdly, based on quotient space theory and the granule computing, this paper divides the Contourlet coefficients into several different sizes. According to the important characteristics of the granule computing, we can embed the watermark information quickly. The quotient space has much stronger representation. This paper discussed the details of how to use the quotient space to solve complex problem.Finally, by analyzing the experiment results, we can see that the watermark information is embedded into all kinds of Contourlet coefficients, which is not only improves the reconstruction quality of image and increases the quantity of embedding watermark, but also improves the operation speed and improve the performance of the algorithm. So the algorithm is feasible and it can be used for the copyright protection.