Research On The Optical Watermark Anti-counterfeiting Technology Of Halftone Information Hiding

As a traditional way of spreading information,printing still plays an important role in modern society.Advances in printing technology have made it easier to replicate and counterfeit,which presents a great challenge for information security,anti-counterfeiting technologies will play an increasingly important role in the security realm,especially in medical packaging,food packaging,notes and securities.At present,the technical research of printing anti-counterfeiting relies mainly on the materials and equipment,which not only increases the cost but also limits the technical popularization.While the digital watermarking technology and visual cryptography technology can implement information hiding,but its application in printing still has many problems and obstacles,so the halftone information hiding technology become the hotspot in research of printing anti-counterfeiting.Based on the research of moire,halftone technology and human visual characteristics,this paper proposed a new method to realize the protection of printed documents.(1)Information hiding model building and experimental verificationAnalyzing the distribution characteristics of printed documents,and exploring the relationship between dot and information transferring.Through the change of location and angle,the phase modulation information hiding model,angle change information hiding model and 3D information hiding model are established respectively.Then,the circular dot and microstructure dot are used to verify the correctness and effectiveness of the model by computer simulation.The results show that the method has good information hiding effect and the watermark information can be well transmitted without affecting the quality of the printed image.(2)Information detection model building and experimental verificationFirstly,the arrangement rules of watermark dot and non watermark dot are analyzed.By matching the dot size and the grating gray level,the equivalentgray level information detection method,the equivalent gray complementary information detection method and the microstructure information detection method are established respectively.Then,the accuracy of the model is tested through experiments.The results show that when the parameter matching grating and the printed image are superimposed together,the watermark part and the non watermark part will show different gray levels under the interference of the light wave,so the hidden information will be clearly reproduced.(3)Study on the influence of anti-counterfeiting effectBy analyzing the human visual characteristics,the effects of different factors on the information hiding and detection effects are studied,the results show that information hiding in the image with a screen angle of 45°,grayscale from 20% to 50%,complex texture can obtain preferable anti-counterfeit effect,and the security effect is the best when the gray value is 30%.The colors of the ink can be cyan,magenta and black.The screen angle can also choose 15° or 75°.The amount of hidden information should be lower than the visual visibility threshold.In this paper,the application of information hiding in printed documents is realized through the research of optical watermarking halftone information hiding and anti-counterfeiting technology.This method only needs to be realized by pre-press design,thereby reducing the anti-counterfeit cost of printed documents,and the information detection method is simple and convenient,which can be directly aimed at the user.In particular,the combination of microstructure dot and information hiding enhances the anti-counterfeiting efficiency and additional function of printed documents,it has a very wide application prospect and value in use.