Digital Image Watermarking Based on DiscreteWavelet Transform
Digital Image Watermarking Based on Discrete Wavelet Transform

This paper aims at digital watermark which is a new popular research topic recently, presents some methods to embed digital watermark based on modifying frequency coefficients in discrete wavelet transform (DWT) domain. First, the present progress of digital watermark is briefly introduced; after that, starting from Pitas’s method and discarding his pseudo random number method, the authors use a digital image scrambling technology as preprocessing for digital watermarking. Then the authors discuss how to embed a 1-bit digital image as watermark in frequency domain. Finally another digital watermarking method is given in which 3-D DWT is used to transform a given digital image. Based on the experimental results, it is shown that the proposed methods are robust to a large extent. This work is supported by the National Natural Science Foundation of China (Grant No. 60133020) and the NKBRSF Project of China (Grant No. G1998030608). DING Wei received the B.A. and M.A. degrees from Jilin University in 1994 and 1997, and Ph.D. degree from the Institute of Computing Technology, Chinese Academy of Sciences in 2000. He is currently a research fellow in Legend Group Ltd. His research interests include digital image and video processing and compression, computer graphics, information hiding, and digital watermark. YAN Weiqi received the B.A. and M.A. degrees from Xibei University in 1992 and 1994. He is currently a Ph.D. candidate of Institute of Computing Technology, Chinese Academy of Sciences. His research interests include computer graphics and digital image information security. QI Dongxu received the B.A. degree from Jilin University in 1963. He is currently a professor of both Macau University of Science and Technology and North China University of Technology. He is still working as a visiting professor of the Institute of Computing Technology, Chinese Academy of Sciences, Jilin University, Xibei University, Zhongshan University, etc. He serves as an editor of many journals, such as Journal of Computers, Journal of Software, Journal of Image and Graphics, etc. His research interests include computer graphics, computer aided geometry design, numerical analysis, and image processing.