说明：  针对打印扫描对图像影响的特点, 选取在图像的DCT 域上嵌入水印信息。对DCT 变换后的系数按 照他们的位置进行了特殊的分类, 通过分类后每一类中正负号的数量来表达水印信息, 增强了算法的鲁棒性。 然后对水印的嵌入位置、鲁棒性和嵌入强度进行了研究
(Impact on the image for print scanning feature, select the image on a DCT domain watermark embedding. The DCT transform coefficients according to their location for a special classification, through classification in each category after the number sign to express the watermark information, to enhance the robustness of the algorithm. Then the location of the watermark embedding, robustness and embedding strength studied)