Research On Halftone Composite Anti-counterfeiting Method And Algorithm

The phenomenon of piracy and infringement of printing products such as technology labels,securities,books,etc.is becoming more and more serious,and people's demand for anti-counterfeiting of these printed matters is also increasing.Research on high efficient anti-replication and anti-counterfeiting technology of printed matter can not only protect the copyright,but also distinguish the original and copy quickly and easily.In recent years,due to the advantages of using halftone image to hide information,such as good anti-counterfeiting effect,low cost,easy to add value-added applications,etc.,it has been widely valued.In this paper,the halftone information hiding method and anti-copying technology are deeply researched,and the multiple halftone composite anti-counterfeiting technology is innovatively studied.Halftone AM(Amplitude Modulation)/ FM(Frequency Modulation)screening image coexists in the same image,which has poor compatibility when it is copied.Using this defect,the watermark(text,number,symbol,etc.)information modulates the AM dot image in the form of FM dot according to the principle of gray level equivalent and texture similar to realize the embedding of watermark information and the anti duplication of image.Fusing halftone information modulation,information hiding,and microprinting technologies,by constructing micro text dot matrix font template,and based on the principle of dual matching of grayscale and morphology,microforms are implanted into the carrier image in the form of microstructured texture,while perfectly reproducing the halftone image,it achieves the purpose of anti-counterfeiting with microtext as the texture,and presents a unique artistic expression effect.A new halftone composite anti-counterfeiting method is proposed to meet the requirements of anti duplication and information value-added service of QR code.This method combines halftone dot information hiding technology with metamerism technology of CMYK(cyan,magenta,yellow,black)color reproduction.Firstly,the anti-counterfeiting information is pseudo-randomly implanted into the ordinary QR code in the form of halftone tiny dots to realize the first-level of information hiding;then based on the principle of equal gray replacement,the second-level of anti-counterfeiting information is implanted into the CMYK color image in the form of metamer to achieve the second-level of information hiding,thus,a QR code with double anti-copying and anti-counterfeiting performance is obtained.The innovation of this paper is halftone screening based on image content characteristics.By analyzing the content characteristics of continuous tone image,the shape,position and angle of halftone dots can be modulated,so that the halftone image can be optimally matched with the original continuous tone images in content features,and the quality of printed matter can be further improved.The combination of metamerism and halftone dot information hiding technology can solves the serious security hole of QR code in anti-duplication,and expands more multi-dimensional information loading space.