New Anticounterfeiting Technology With Two-dimensional Bar Code

For the anticounterfeiting of printings(such as certificate),the existent many ways ( such as rainbow holograms ) are not available as the need for special use:anti-distortion and anti-copy.Basing in the double-random-phase transform,this article puts forward a new way that two-dimensional bar code is used as anticounterfeiting label with anti-printing–scanning and anti-damage properties. The major job are :(1).Basing in the ASCII codes, numerals and alphabets are encoded and subsequently transformed into two-value bar code matrix figure .Later,using amplitude-based double-random-phase transform,the enciphered gray scale figure is formed . By computer simulation(4f system) and printing as well as scanning(20 times),we get the result that the gray scale figure with little miscoding rate(0.0026) by"Matrix expanding way".(2).We consider fully phase double-random-phase way to form gray scale figure.By computer calculation and experiments,we get the result that the miscoding rate of decoding is little(0.0174) even if 1/4 area of gray scale figure is damaged.(3).By DFT and DCT as well as FRT ways , unviewable symbols are hided into gray scale figure to realize anticounterfeiting.This article provides theory basis and experimental verified datas for making practical encoded bar code labels.