基于四元数傅里叶梅林变换的RST不变彩色图像水印算法

RST Invariant Color Image Watermarking Algorithm Based on Quaternion Fourier-Mellin Transform

提出一种基于四元数傅里叶梅林变换(QFMT)的RST(旋转、缩放和平移)不变彩色图像水印算法,利用图像的不变质心生成具有平移稳定性的圆形特征区域,对这个圆形区域进行QFMT。利用QFMT幅度谱具有旋转和缩放不变性,在QFMT幅度谱中嵌入水印信息。该算法不仅可以抗RST攻击,大大提升水印的鲁棒性,而且可以把水印嵌入所带来的误差扩散到载体图像的各个颜色分量之中,扩大水印嵌入的容量。实验结果表明,该方法具有较好的抗压缩性,对RST等攻击有良好的鲁棒性。

In this paper, a RST （Rotation, Scaling and Translation） invariant color image watermarking algorithm is proposed by using Quaternion Fourier-Mellin Transforms （QFMT）. Firstly translation invariance is achieved by circular feature region which can be generated using invariant centroid. Then the circular region is transferred into QFMT domain. Rotation invariance and scaling invariance are constructed by embedding the digital watermarking into the QFMT spread spectrum. The proposed color im- age watermarking scheme is of better robustness against RST attacks. And the proposed algorithm spreads the image distortions from the watermarking into the three channels of host image, thus leading to an increased capacity of watermarking embedding. Experimental results demonstrate that this method is of good robustness against JPEG compression and RST attacks.