基于圆谐-傅里叶矩的数字水印算法

针对几何攻击对数字水印的巨大破坏性,提出一种抗几何攻击水印算法,将水印信息隐藏于图像圆谐-傅里叶矩的幅度变化中。进行水印检测时只要比较受攻击图像的圆谐-傅里叶矩与密钥的差别,就能提取到水印序列。实验结果表明,该算法对旋转攻击、缩放、JPEG压缩和其他噪声攻击具有良好鲁棒性。     

基于切比雪夫矩的抗几何攻击图像水印

旋转、缩放和平移(RST)等几何攻击能够破坏水印检测的同步性,而使水印检测失败。本文提出了基于切比雪夫矩的抗几何攻击图像水印算法.首先计算原始图像的切比雪夫矩,并将其作为原始矩,然后将水印图像在空域直接嵌入到原始图像中,并提取嵌入区域的切比雪夫矩。当图像未受攻击时,利用嵌入区域的矩与原始矩之差便可以提取出水印图像。当图像受到攻击后,利用上述方法同样可以提取出水印图像,但是我们需要将原始图像做相应的变换。与使用Zernike矩相比,切比雪夫矩具有更好的图像描述能力。当水印图像的目标物体较小时,切比雪夫矩可以较好的提取出水印图像,而Zernike矩则无法做到,同时该算法对于旋转、缩放、噪声攻击也具有较好的鲁棒性。     

Geometrically robust image watermarking based on Jacobi-Fourier moments

Rotation, scaling and translation （RST） attacks can desynehronize the watermark detection so that many watermark systems failed. A geometrically robust image watermarking strategy based on Jacobi-Fourier moments （JFMs） is proposed. The Jacobi moments of the original image are first extracted as original moments; then the watermark image is embedded into the global or local area of the original image, and the Jacobi moments of the area are extracted. When the watermarked image is not attacked, the watermark can be retrieved by using the margin of the original moments and the moments of the embedded area. When it is attacked, the watermark can also be got in that way, and the original moments need to be transformed. It can be concluded that Jacobi- Fourier moments perform better than Zemike moments （ZMs） for small images. Meanwhile, the watermark is also robust to scaling and rotation as well as regular attacks such as added noises.