Algorithm Study On Color Image Digital Watermark Based On Wavelet Transform And HVS

with the development of digital technology and intemet, digital multimedia has become chief means of information communication. While one can acquire a wide range of multimedia products through the Internet. But the insecurity and the advantage of digital products are equally existence,copyright violation, illegal copying, easy forging, etc. How to protect multimedia products from violation has become an important issue in information security field. As an effectual means to protect the digital product's copyright, the digital watermark technology is being researched and used popularly. This technology embeds the watermark which indicates the author or the copyright owner's information of the digital products into the original medium through some algorithms. It doesn't affect the use of the original medium, but only need to extract the watermark which is used for judging the medium's copyright owner if there iscopyright dispute.A watermarking technology for image copyright protection in wavelet domain is researched in the paper. The principle, typical algorithms, attack analysis and evaluation of performance of digital watermark is firstly described. Then, aim at the research and the problems which are exist to be considered and solved, a watermarking algorithm based on the discrete wavelet transform and human visual system is proposed. The algorithm chooses low and middle sub band of the wavelet packet decomposition of the original image to embed the watermark, which increases the capacity of the watermark and improves the imperceptibility also. With the combination of HVS model, the robustness of watermark is raise. Quantity of experiment data shows that the algorithm has good robustness on image attacks (JPEG compression, filter, noise, cropping, etc.), and the imperceptibility of watermark can be guaranteed at the same time.