Method for realizing color image digital watermark for certificate anti-counterfeiting

Abstract

The invention relates to a method for realizing a color image digital watermark for certificate anti-counterfeiting and belongs to the technical field of anti-counterfeiting and information security. The technical scheme comprises the following steps of: 1, converting an RGB color space of a color image to an L*a*b* color space; 2, encoding and modulating readable watermark information to generate a colored noise watermark mode; 3, taking an increasing function related to a gradient modulus as a visual control factor; 4, embedding a watermark into an L* luminance component of the L*a*b* color space; 5, performing predictive filtering pretreatment on a watermark image before extracting the watermark and then extracting the watermark by a normalized correlation method; and 6, decoding bits of the extracted watermark into the readable watermark information. The method of the invention improves the correct extraction rate of watermark signals. The scheme has high robustness for resisting printing and scanning attack and can be widely used for the anti-counterfeiting of various certificates.

Description

technical field The invention relates to the technical field of anti-counterfeiting and information security, and is a color image digital watermark technology that can embed hundreds of bits of watermark information in a color image and resist printing and scanning attacks and can be used for certificate anti-counterfeiting. Background technique By consulting relevant materials and related patents, the following patents are mainly cited: Country name Patent publication number Date of authorization announcement 1. China CN1322470 2007.06.20 2. China CN100559396 2009.11.11 3. China CN1960428 2009.01.14 4. China CN100511277 2009.07.08 The printing and scanning problem is a crucial problem in the future application of digital watermarking. If this problem is solved, paper media including books, newspapers, magazines, etc. can use digital watermarking for copyright protection. In addition, digital watermarks can be used to verify the authenticity of bills and cer...

AI Technical Summary

Problems solved by technology

(1) Printing in the process of document production and scanning in the process of authenticity identification have caused great attacks on digital watermarks, mainly including geometric attacks and halftone attacks

In addition, the wear and tear of the certificate during use also caused certain attacks on the watermark.

These attacks lead to difficulties in extracting watermark information, which limits the wide application of digital watermark technology for document anti-counterfeiting

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