提出一种基于四元数离散傅里叶变换QDFT(Quaternion Discrete Fourier Transform)和四元数离散余弦变换QDCT(Quater-nion Discrete Cosine Transform)以及四元数奇异值分解QSVD(Quaternion Singular Value Disposition)的双重零水印算法。首先将彩色图像用四元数模型表示并进行分块四元数离散傅里叶变换,通过比较各块的部分系数幅值大小产生二值序列;然后,对各原图像块进行离散余弦变换和奇异值分解,利用奇异值矩阵和左右四元数矩阵的幅值来产生另一个二值序列。将二值序列与版权信息相结合产生零水印,并将零水印在知识产权IPR(Intellectual Property Right)中心注册。实验表明,该算法对常见攻击、部分组合攻击及未来可能的一些攻击方式具有较强的鲁棒性。
This paper presents a double zero-watermarking algorithm,it is based on quaternion discrete Fourier transform (QDFT),quaternion discrete cosine transform (QDCT)and quaternion singular value decomposition (QSVD).First,we represent the colour imagewith quaternion model and carry out chunked QDFT,generate a binary sequence by comparing the amplitude sizes of partial coefficients ofeach block.Then,we apply QDCT and QSVD to each original image block,and use the amplitudes of singular value matrix and aroundquaternion matrix to generate another binary sequence.At last,we combine the binary sequence and the copyright information to producezero-watermarking,and register it in intellectual property right (IPR)centre.Experiments show that the algorithm is very robust to commonattacks,some composite attacks and some possible future attacks.