为了提高空间域彩色图像零水印算法的水印嵌入和检测精度以及抵抗旋转几何变换的能力, 提出了一种基于Radon变换和四元数实矩阵表示的抗旋转攻击空间域零水印算法。首先将原始彩色图像使用四元数实矩阵来表征, 并计算实数字矩阵的Radon变换不变矩; 然后利用少量低阶Radon变换不变矩来设计和构建零水印信息; 在水印检测前, 通过Radon变换几何校正算法对可能遭受旋转攻击的待检测图像进行旋转角度的校正, 然后进行水印的提取。实验结果表明, 该方法可以获得良好的图像视觉效果, 对于旋转几何攻击具有很强的鲁棒性, 同时对滤波、JPEG压缩和剪切攻击也具有一定的鲁棒性。

In order to improve the accuracy of the embedding watermark and the ability to resist rotation geometric transformation, a zero watermarking algorithm based on Radon transform and real matrix of quaternion is proposed. Firstly, using the real matrix of quaternion to represent the original color image, and calculate the Radon transform invariant moments of the real matrix. Then, some low orders Radon transform invariant moments are used to design and construct zero watermarking information.Before the watermarking image is detected, the rotation angle of waiting detection image that the rotation attact may be subjected is corrected. Then the watermark is extracted. The experiment results show that the proposed method can obtain better visual effect, it is robust enough to rotation attack, meanwhile, it is also robust enough to some mage degradation process such as filtering ,JPEG compression and cropping attack.