A NEW WAVELET-BASED DIGITAL WATERMARKING ALGORITHM

Watermarking technology has become an important method to protect the multi-media information. The watermarking algorithms based on wavelet transform have received more and more attention since the wavelet transform matches the human vision system model. However, the wavelet transform does not have the ability of geometric resistance. So most of the proposed watermarking algorithms based on wavelet transform are not resistant to geometric attack. For instance, the detection of watermark fails if the watermarked image is rotated by a very small angle. In order to add the ability of geometric resistance to wavelet based watermarking algorithms, a blind digital watermarking algorithm based on integer wavelet transform is proposed in this paper. In this algorithm, a template is embedded into the watermarked image. Using the template, the image can be correct after the geometric attack to make the watermarking detection and embedding courses be synchronization again. In this way the watermark could be extracted exactly. The experiment results show that this algorithm is robust and effective to geometric attack.