在对原图像进行双正交7／9三级小波分解后 ，在第二级的水平、垂直直、对角和第三级对角分量上加入水印系数，再经过小波反变换重构出图像。 -After the original image biorthogonal 7/9 three wavelet decomposition, at the level of the second stage, the vertical straight, diagonal and the third stage, added to the angular c