Research On Security Printing Technology Based On The Halftone Holographic Watermark

Now print is still the main media for bearing important data in thefinancial, legal, commercial transactions fields. In the wake ofimprovement in all global economy conditions and science technology,all kinds of malicious counterfeit crimes have become more and morerampant, which makes the requirement of people for the printinganti-counterfeiting technology enhance continuously. The purpose of thisresearch is to make the holographic digital watermark technology appliedto printing anti-counterfeiting technology, and combined with digitalhalftoning technology. This method would use a combination of varietyof advanced anti-counterfeiting technology, in order to achieve a multipleencryption, high safety, low-cost printing anti-counterfeiting technology.Firstly, we finished the programming of digital halftoning, Fresnelholographic transform and digital watermarking process throughcomputer simulation software MATLAB. And according to thecharacteristics of human visual, the evaluation method was setted up forwatermarking system.Secondly, on the basis of the above work, in order to further enhancethe ability of the security information resistance to printing and scanning,this paper studied the principle and characteristics of the color printingtechnology, and designed a kind of color prints holographic halftonewatermarking algorithm based on discrete Harr wavelet transform. In thealgorithm, the digital halftoning, Fresnel holographic transform anddiscrete Harr wavelet transform are all introduced into the digitalwatermark encryption security system.Finally, the print-scanning experiments are carried out for thewatermark algorithm suggested in this paper, so as to test algorithmrobustness and adaptability. The experimental results show: the algorithmhas good invisibility. Meanwhile, the concealment is better under thecircumstance of embedding the watermark into the channel of more colorcomponents. As the color components of color host image are different,the best channel to embed watermark is also various. And for commoncolor images, the robustness of the watermarking is the worst in black channel. In addition, the brightness and contrast of images is no influenceon the robustness of the watermarked system. Not only do the surfacecharacteristics of paper have an obvious effect on the quality of printingproducts, they have a significant impact on the watermark. For thepaper-base in the same category and brand, its weight and thickness haveno obvious influence on the robustness of the watermarked system. Andon the condition of using the same kind of paper, the influence of thedifferent screen line number is also not noticeable. The higher thescanning resolution is, the clearer the extracted watermark would be.This paper makes a more in-depth analysis and research to thecalculation holographic, digital halftone, digital watermarking technologyand discrete Harr wavelet transform in printing anti-counterfeiting. Thedesigned watermarking algorithm has a strong ability for technologicalattack in the resistance to printing-scanning process, and would becomean effective means of printing anti-counterfeiting technology.