抗打印扫描数字水印算法的鲁棒性

Robustness Investigation of Digital Watermarking Algorithm for Print-and-Scan Process

提出了一种能够抵抗打印和扫描的数字水印算法。算法的关键在于强鲁棒性。首先分析了打印扫描对图像的影响,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。由于该算法对打印扫描的鲁棒性,可用于印刷图像的版权保护和认证。

A novel digital watermarking algorithm for print_and_scan process is proposed. The key of this algorithm is its strong robustness. First, the effect of printing and scanning for images is discussed. According to the characteristic of the effect, the digital watermarking is embedded on the DCT domain of images. Especially, the DCT coefficients are classified by their position. After classify, the digital watermarking is expressed by the count of difference between the positive and the negative in each group, and the robustness is enhanced. Then, the relation among the position, robustness and intension is studied in detail. Since this algorithm is robust for printing and scanning, it can also be used in copyright and authentication purposes of digital image for the printed format.