Research On Contourlet Domain Digital Image Watermarking Algorithm

With the rapid development of multimedia and Internet, the security of multimedia has been a significant and challenging research topic. Digital watermarking technology has been attracting more and more attention due to its possibility to solve the problem and now is the hot point in information security.This paper introduced the research background and meaning of watermarking technology as well as the main work. Then the concept, characteristic, classification, application and design principle of the digital image watermarking scheme are involved. Also, a new multiresolution transform called contourlet transform is further analyzed. Based on current search, this paper presents two kinds of image watermarking scheme.In the first watermarking scheme, a three-level contourlet transform is applied to the host image. The scrambled watermark is embedded and extracted in the contourlet coefficients which are selected by the human visual system using the quantization index modulus modulation. The simulation results indicate that the scheme is robust to such digital image processing as JPEG compression, smoothing, sharpening and cropping.In the second watermarking scheme, two-level contourlet transform is applied to the host image. The watermark is scrambling encrypted and then further processed using the spread spectrum technology. At last the watermark is embedding in the last level contourlet coefficients based on neighboring mean value relationship. Simulation results indicate that the scheme is robust to such geometrical attacks as rotation and scaling.