The Research Of Digital Watermarking Algorithm For Print-Scan Attack Process

Because of the development of printing technology, illegal behavior using forged print product has become much easier and hard to control. In order to achieve the security, distinguish and tracing of print product, digital watermark has become the research focus in the data-hiding field.This paper analyzes the features in working process of print-scan device and the effect of working process on the digital image, then summarizes the rule of distortion of image. This research provides theoretical basis for establishing the digital watermark system resist print-scan process.Through the study of the unchanged pattern of the DWT coefficients after the print-scan process, this paper presents a watermarking algorithm system based on the relation of DWT coefficients., meanwhile, feature points of image is used for geometric correction in recovering process, effectively increase the robustness of the system. Experiments shows that this algorithm performs well in print-scan experiment.This paper combine the Minimal Brightness Variation Criterion (MBVC) and the Artificial Neurons model, presents a halftone watermarking algorithm which embedding the watermark information during the halftone process. This algorithm uses MBVC in quantization rules, embeds the watermark information in the image by training and adjusting the weight. Through this algorithm we can get a high-quality halftone image, and experiments shows that it has a good performance against regular attack and print-scan process.