Digital watermarking for print and scan process based on gray image
Qing Zhou · Microcomputer Information · 2009
Based on continuous hyper-chaotic system and discrete Cosine transform, this paper presented a blind detection watermarking algorithm for gray image to hide information against print-scan process. 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, then, according to the principle of HVS, the embedded locations was selected. The digital watermarking is expressed by the count of difference between the positive and the negative in each group, and the robustness is enhanced. Since this algorithm is robust for printing and scanning, it can also be used in copyright and authentication purposes of digi- tal image for the printed format.