Printing and scanning resilient watermarking method based on mathematical modeling

Abstract

The invention relates to a printing and scanning resilient watermarking method based on mathematical modeling, comprisng the mathematical modeling and correction of pixel distortion, watermark embedment and watermark detection. Mathematical modeling and correction of pixel distortion carries out mathematical modeling to the pixel distortion of an image brought by digital halftoning, dot gain, gamma correction, quantification and other links during a printing and scanning process and corrects the pixel distortion based on mathematical modeling so as to improve the watermark detection accuracy. Watermark embedment conducts analysis based on the mathematical modeling to determine an appropriate embedded domain, further investigate the impact of embedded watermarks at different positions in the embedded domain on the robustness and capacity of watermark algorithm and the fidelity of the image and determine the reasonable embedding positions of the watermarks. Watermark detection corrects the image to be detected and extracts the watermarks according to a model curve of the changed embedded domain before and after image printing and scanning obtained from mathematical modeling analysis. The invention corrects the pixel distortion that the printing and scanning process to the image by mathematical modeling, fits the model curve through a large amount of experimental data, corrects the printed and scanned image with the obtained model curve, detects the watermarks of the corrected image and can effectively improve the accuracy of watermark detection; and novel printing and scanning resilient digital image watermarking algorithm based on DWT and DFT is presented by integrating the pixel distortion mathematical modeling and correction, and the novel algorithm carries out pixel distortion mathematical modeling and correction on a wavelet approximation subgraph of the image.

Description

technical field [0001] The invention relates to a multimedia digital watermark embedding and detection method, in particular to a mathematical modeling-based anti-printing and scanning watermarking method. Background technique [0002] The development of modern digital multimedia technology enables people to easily realize the "seamless" modification of multimedia data; and the development of the Internet makes it easy for people to disseminate and obtain various multimedia data, making the infringement and content tampering of digital products a reality. It is difficult to guard against. Therefore, how to effectively authenticate and protect the integrity of information is an urgent technical problem to be solved. In order to ensure the credibility of multimedia data, a technology that protects multimedia data by verifying the integrity of data information, the reliability of data sources, and the authenticity of data—multimedia authentication technology emerged as the tim...

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Problems solved by technology

Xu (see Hongping Xu, Xiaoxia Wan, "Watermarking Algorithm for Print-scan Based on HVS and Multiscale Error Diffusion", 2008 International Conference on Computer Science and Software Engineering, pp.245-248, 2008.) proposed a human-eye-based visual system (Human Visual System, HVS) and multi-resolution error diffusion anti-print scanning algorithm, the algorithm also embeds watermark information in the halftone image, based on HVS, the algorithm obtains high image fidelity, and at the same time, the algorithm capacity is also large Relatively large, it can reach hundreds of bits, but like the previous algorithm, geometric transformation is basically not considered, so it is not applicable in the case of large geometric transformation

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