关键词: 分形水印, 几何攻击, 分形编码, 伪Zernike矩, 量化调制

Abstract: A new image watermarking scheme robust to geometric attacks was proposed based on fractal coding and pseudo-Zernike moments. Firstly, the original image was divided into two groups: self-similarity blocks and non-self-similarity blocks by fractal coding and pre-set threshold. Then, the most robust pseudo-Zernike moment was picked up among the pseudo-Zernike moments of the self-similarity blocks. Finally, the watermark was embedded by quantizing the magnitudes of the most robust pseudo-Zernike moment. The experimental results show that the scheme is not only invisible and robust against common signals processing such as median filtering, sharpening, noise adding, JPEG compression, etc, but also robust against the geometric attacks such as affine transform, local geometric distortion, etc.

Key words: fractal watermarking, geometric attack, fractal coding, pseudo-Zernike moment, modulation by quantizing