Research And Implement Of Color Image Digital Watermarking

As a new method in copyright protection, certification, covert communications of digital products, digital watermarking technology has attracted a great deal of interest and concern, and has been widely studied and applied in recent years.First of all, this paper introduced the principle of image digital watermarking technology, the elementary knowledge and the present research situation. Most of the current research is binary and gray image watermarking, lacking of color image watermarking, especially double color image watermarking. Compared with binary, gray-scale image, taking color image as watermarking has irreplaceable advantages. It is visual, rich, vivid, much copyright protection information contained, more easily identified by the human visual. Considering the robustness of watermarking, the transformation domain image watermarking algorithm is widely used. But it has limitations of embedded information capacity. Because human visual is sensitivity to color, which makes the invisibility of watermarking difficult to guarantee, double color Image watermarking has not been studied in depth. In order to solve the problems above, this paper presents a scheme of double color image digital watermarking, which uses the color image of much information capacity as watermarking, trying hard to improving robustness based on unperceivable.Then, this paper analyzes the problem that much information capacity watermarking embedded leads to reduction of invisibility and robustness, and designs a combinatorial algorithm combining with masking characteristics of the human visual based on tins. This algorithm embedded watermarking in suitable region, making it unperceivable and improving the invisibility of watermarking. In order to improving the robustness based on unperceivable watermarking, this paper analyzes the characteristics of the transformation domain different frequency coefficients, and determines appropriate frequency coefficients combining the characteristics of human visual masking frequency. And the algorithm preprocesses watermarking, the watermarking suits embedded. Finally, through the analysis of the invisibility and robustness of watermarking, this paper designs a method of using different embedding strength, which makes the invisibility and robustness of watermark be well balanced. The experiments show that color watermarking can be embedded to color images of different types, and the embedded watermarking is unperceivable. Through the test, it is proved that the algorithm is robust to common attacks.