Abstract: This paper presented a novel anti-geometric-attack digital image watermarking algorithm based on pseudo-Zernike moments and Contourlet transform knowledge.It uses Contourlet transform to extract low frequency sub-band of the image.We embeded the digital watermark information into this low sub-band by quantizing the magnitudes of the selected pseudo-Zernike moments,according to the human visual system (HVS) and the correlation between the coefficients of the embedded watermark before and after.Without the aid of the original image,the watermark can be extracted and the real blind detection is realized.According to the experimental results,the proposed watermarking algorithm has the best resistance to shift transform,and has good resistance to rotation and zoom.After JPEG compression,the digital watermark is not distorted.

Key words: Image watermarking,Geometric attacks,Contourlet transform,Pseudo-Zernike moments,Low sub-band