—种DCT与SVD相结合的数字图像水印算法

文章结合奇异值分解（SVD）和离散余弦变换（DCT）的特点，提出了一种基于DCT与SVD分解的数字图像水印算法。该算法能够很好地解决透明性和鲁棒性之间的矛盾。算法中采用经过置乱变换的灰度图作为水印，不仅增加了嵌入的信息量，而且提高了水印的安全性。实验结果表明，该算法不仅具有较好的透明性，而且对常见攻击如：叠加噪声、JPEG压缩、滤波以及几何攻击等具有较好的鲁棒性。

A Combination of DCT - based and SVD - based Watermarking Algorithm

A new watermarking algorithm for digital image base on DCT and SVD is proposed in this paper,which combines both merits of discrete cosine transform（DCT） and singular value decomposition（SVD）.The conflict between transparence and robustness of the watermark system is better solved by the algorithm.In the scheme,the embedded watermarking images are gray images which are scrambled,thereby increasing embedded information capacity and guaranting the safety of data.Experimental results show that the new watermarking scheme has a good transparence of embedded watermark image and is robust against attacks such as adding noise,filtering,JPEG compression and geometric distortion.