Image Watermarking Robust to Four-Color Printing and Fragile to High Resolution Copy

A blind print-scan (PS) resilient watermarking scheme is proposed in this paper. In general, a duplicated one can be obtained by high resolution scanning and printing the first printing. How to distinguish watermark quality from the first printing and the duplicated one? To solve this problem, error correction of coding is used to resist the first printing and scan processes first. Second, a suitable strength parameter to watermark is selected to balance and distinguish the fist PS and twice PC. Finally, some statistic in the space domain is computed to adjust watermark extraction after the watermarked images is first printed and scanned. The cover image is not needed when the watermark is detected. Experiments results show that the scheme can resist first printing and scan process. Furthermore watermark cannot be extracted from the duplicated one. The scheme is also robust to geometrical transformation, noise, compression, cut and so on.