Research On Reliability Encoding And Decoding Algorithms For Printed Quantum Dots Information

Printing quantum dots(halftone dots)are used to record information and load it into images for information hiding and anti-forgery,which has become a research hotspot in the field of anti-forgery of printing information in recent years.However,in the process of transmission,the printing quantum dot information is missing or added due to the problems of color bias,paste,dirty plate caused by the printing equipment,and in the process of image acquisition,there are inevitably problems such as uneven illumination,shooting angle and so on,which make the printed quantum dot information noisy,resulting in low recognition rate and accuracy of mobile phone.Therefore,it is of great practical value to study it in depth.A reliable codec algorithm is designed to solve the problem of information point loss and leakage caused by the information dot matrix image using printed quantum dots as carrier during printing and transmission.The algorithm combines the secret information with the digital signature encrypted by Hash after binary conversion and pseudo-random permutation to prevent tampering during transmission,resulting in errors in the information presented.Then,the random noise and burst noise during transmission are solved by channel coding method of convolution code and interleaving code.Then,the encoded data stream is reorganized to generate a bitmap,which is scrambled with the data mask.Synchronization information and encoded data mask information are implanted at the same time to facilitate data positioning during reading.Finally,according to the low visibility of the blue channel in RGB image combined with halftone screening technology,the printed quantum dot image after two-dimensional dot matrix copying and splicing is embedded in the B channel of the carrier image to generate the corresponding printed quantum dot anti-forgery image.In the process of reading printed quantum dot anti-forgery image,a new algorithm for reading printed quantum dot anti-forgery image information is presented to solve the problems of high error rate and slow speed in the process of reading such image information by mobile phone.Firstly,the image is preprocessed with the adaptive Otsu method to remove the interference information such as bottom gray,uneven lighting,and background texture.Secondly,the local pixels of the whole image are taken as samples,and the tilt angle of the printed quantum dot matrix is estimated by calculating the dispersion of the gray distribution of the sample pixels.Then,the sequence between printed quantum dots is determined according to the pulse width modulation waveforms projected on the X and Y axes of the image,and rasterized with the tilt angle of the printed quantum dot matrix.Finally,at each intersection of the raster,calculate the corresponding lattice information based on the spacing between adjacent raster to recognize noise tolerance,and the lattice data for extracting printed quantum dots is traversed.Finally,the extracted printed quantum dot matrix data is decoded,decoded and decrypted according to the inverse process of anti-counterfeiting image generation,and the secret information is extracted.This article generates printed quantum dot anti-forgery image by combining halftone information hiding,information security encryption,reliable codec and blind synchronization information positioning in modern digital communication.The experimental results show that the algorithm can effectively solve the random and unexpected errors caused by missing prints,smudges,etc.in the print quantum dot anti-forgery image,and improve the reliability of information transmission.At the same time,the mobile phone reading information rate can be stable at 0.5s.This algorithm can be effectively applied to the information protection of printed products,and has broad prospects in the field of anti-forgery printing information.