Abstract: An algorithm based on wavelet transform for hiding digital watermark in image is presented. In this algorithm, a 2level DWT decomposition of the original image is performed and then the important perceived factors are adopted by certain strategies as a watermark embedding regions. The watermark is embedded into the lowfrequency subband repeatedly in order to improve the accuracy of the watermark detection. Test results show the good transparency of the watermark and the good robustness of the algorithm for the best known attacks such as noise interference, image compression/clipping and other image processing actions.

Key words: digital watermark, Discrete Wavelet Transform (DWT), image scrambling, blind detection