基于对数极坐标下的SVD数字水印算法

A Digital Watermarking Algorithm Based on SVD and Log-polar Coordinates

为了解决笛卡尔坐标系下水印不同步问题文章提出了一种对数极坐标系下的基于奇异值分解的抗旋转,缩放攻击鲁棒性水印算法。对于旋转,缩放造成的几何攻击,我们可以通过对数极坐标系将笛卡尔坐标系中的旋转,缩放变换转换为循环平移的性质,对于循环平移后的图像,在水印检测时我们可以使用穷举遍历的方法来检测测试图像是否包含水印信息。实验结果证明,该方法可以获得良好的图像视觉效果,同时对于加噪,滤波,JPEG压缩,剪切攻击也具有有很好的鲁棒性。

In order to solve the watermark non-synchronization on Cartesian coordinate,this paper proposes one method resisting to Rotation and scaling based on logarithm polar coordinate,which can against rotation attack ability efficiently.For rotation causing distortion,we make use of LPM（log-polar maping）,which can transform rotation problem in Castesian coordinate to translation property in LPM coordinate.After translation,we use an exhaustive search to detect test image involves watermarking or not.The experiment results demonstrate the proposed method can obtain better visual effect,meanwhile,it is robust enough to some image degradation process such as adding noise,cropping,filtering and JPEG compression.