基于块奇异值分解的小波域数字水印算法

根据小波变换和奇异值分解理论的原理、特点以及它们在数字水印领域中的应用优势，提出一种基于块奇异值分解的小波域水印技术.充分利用小波和奇异值分解的优点，结合JPEG方案中分块的思想，首先对宿主图像进行小波变换，对变换后的低频系数再进行块奇异值分解，选取每块中最大奇异值组成新矩阵以嵌入水印信息.在检测时，提出采用多方案水印提取算法以适应不同的攻击.实验表明，该算法对图像退化处理或攻击均具有较强的鲁棒性.

Digital Watermarking Algorithm Based on Block SVD in Wavelet Domain

According to the principles,characteristics and the advantages of the application of DWT and SVD theory in watermarking field,this paper presents a singular value decomposition of block-based watermarking technology in wavelet domain.The decomposition advantages of wavelet and singular value are made full use of.In accordance with the idea of carved blocks in JPEG program,wavelet transformation is firstly made to the host image.Then singular value decomposition is done to the low frequency parameters.The largest singular value of each block is selected to a new matrix to be embedded into water-mark information.Moreover,multiple extraction methods is presented to cope with various attacks.Experimental results show that the algorithm is robust enough to some  image degradation process.