目的 研究针对打印扫描盗版方式的数字水印防伪算法。方法 结合矩阵奇异值分解 （SVD） 的抗几何畸变特性和离散小波变换 （DWT） 多分辨率分解特性， 提出一种基于CIE1976L*a*b*颜色空间的彩色图像数字水印防伪算法， 并通过仿真实验评价算法的有效性。结果 含水印彩色图像与原始彩色图像的色差均值为1.2183， 小于3， 且提取的水印中至少有1个水印有效， 其相关系数均满足R>0.6。结论 在保证水印不可见性的同时， 该算法对打印-扫描操作及大多数常规图像处理具有很好的鲁棒性。

This study focused on watermarking algorithm for security targeting at the piracy approach of printing and scanning. According to the character of resisting geometrical transformations of singular value discrete (SVD) and multi-resolution transform of discrete wavelet transform (DWT), a watermark algorithm was proposed which based on CIE1976L*a*b* color space. And through the simulation experiment, the efficiency of the algorithm was evaluated. The E value between the watermarked color image and the original image was 1.2183, which was less than 3. And at least one of the watermarks which were extracted from the image was effective, the R value was larger than 0.6. The algorithm can insure the watermark to be invisible and is robust against common printing and scanning process or image processing operations.