Research On Anti-print-scan Watermarking Technology Based On Wavelet Transform

With the widely application of multimedia technology, Internet has become the main approach for people to gather information. Nowadays, people can not only dispatch their digital information products easily via Internet, but also can gain them the same way. However, these digital products can be duplicated and modified so unbendingly that how to protect the benefits of owners. Fortunately, a watermark takes its role in these fields, by which one can trace or identify the source of the illegal products by embedding identifications either visible or invisible in them. But, if these digital products are printed and then scanned, most information will lost due to re-sampling and color space converting. And it is still very difficult to develop a watermark algorithm solving this problem.This paper proposes a blind watermark algorithm which resists against printing and scanning robustly. Firstly, we embed an error-correction code in the watermark image to improve its robustness. Then, scramble the embedded image under a secret key. At last, add the watermark image into the important factor tree in wavelet domain. By this approach, we enhanced the unperceivable property as well as robustness. Experimental results show that this algorithm is very robust against printing and scanning, compression, noise and tailoring. The algorithm can be used to the protection and authentication of printing image's copyright.