Digital watermarking method applied to counterfeit prevention for print documents
A technology for digital watermarking and printing documents, which is applied in image data processing, image data processing, instruments, etc., and can solve problems such as small capacity, difficult multi-layer watermarking, and large noise
Inactive Publication Date: 2012-03-07
BEIHANG UNIV
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The multi-layer optical watermarking based on dot matrix proposed by Huang and Wu in 2007, which is based on the principle of modulation and demodulation, is implemented using the phase modulation method, and then Lu Yifeng proposed the optical watermarking based on the Monet phenomenon in 2008. Compared with the optical watermark based on dot matrix, the Monet phenomenon is formed by the interference of black and white stripes, so it has relatively large noise, it is difficult to realize multi-layer watermark, and the capacity is small
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[0041] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.
[0042] The overall flow chart of a digital watermarking method for anti-counterfeiting of printed documents of the present invention is as follows figure 1 shown. The overall process includes watermark contrast analysis, anti-scan / copy watermark layer, watermark embedding and watermark extraction.
[0043] 1. Watermark contrast analysis
[0044] The research route of this part includes four steps: step a1, factors that affect human visual recognition of objects; step a2, propose the concept of watermark contrast; step a3, analyze the effect of watermark extraction; step a4, choose the appropriate embedding cycle and angle. details as follows:
[0045] Step a1: Factors Affecting Human Visual Recognition of Objects
[0046] Since the watermark extraction effect is obvious to the human eye, but cannot be measured on a computer, it i...
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The invention discloses a digital watermarking method applied to counterfeit prevention for print documents, wherein a multilayer watermark is used for preventing counterfeit of the print documents so as to protect the print documents. The method comprises two aspects of constructing the multi-layer watermark and constructing an anti-scanning / copying watermark layer, wherein the multi-layer watermark is constructed by firstly utilizing factors which mainly comprise contrast ratio and chromatic aberration and influence human vision on identifying objects, providing a concept of watermark contrast ratio by combining with a used scene in the method, further judging factors influencing an watermark extraction effect according to the watermark contrast ratio, finally comprehensively analyzing results and designing parameters; and the anti-scanning / copying watermark layer which is weak to scanning / copying is designed by firstly analyzing a scanning process and summing the features of scanning, therefore the purpose of preventing counterfeit due to scanning / copying can be achieved. The final multi-layer watermark is finallyformed by combining the multi-layer watermark with the anti-scanning / copying watermark layer.
Description
technical field [0001] The invention relates to a multimedia digital watermark construction, embedding and detection method, in particular to a digital watermark method for anti-counterfeiting of printed documents. Background technique [0002] At present, printed documents such as various certificates, bills, and trademarks play an irreplaceable and important role in people's lives. However, with the continuous popularization of digital technology and the rapid development of Internet technology, problems such as forgery and piracy are becoming more and more serious. How to protect these documents Products that are closely related to us, namely copyright protection, information security, data authentication and access control, etc., have become urgent problems to be solved now. [0003] Commonly used anti-counterfeiting technologies for printed documents include paper anti-counterfeiting, special ink anti-counterfeiting, self-adhesive micro-text printing anti-counterfeiting...
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Inventor 陈真勇刘永波范围熊璋
Owner BEIHANG UNIV