Research On Dynamic Metamerism Grey Component Replacement Algorithm With High Accuracy

The application of metamerism in the field of image anti-counterfeiting and information hiding has the advantages of low anti-counterfeiting cost,good hiding effect,easy to detect and high compatibility with other anti-counterfeiting technologies,which makes it a research hotspot in the field of printing anti-counterfeiting.However,some problems of the approach,such as single metamerism information hiding effect,inflexible dynamic adjustment of anti-counterfeiting information,anti-counterfeiting area be limited,and so on.In addition,in the process of color reproduction,it is often based on empirical parameter adjustment method,which lacks the mathematical basis range of replaceable,so the research in this direction has important practical value.To solve the above problems,this thesis puts forward the research of the algorithm of grey component replacement based on large dynamic and high precision metamerism.Firstly,the data used for color space conversion by various algorithms,such as Neugebauer equation method,Neural network method and Polynomial regression method,are designed.After experimental comparison and analysis,a better method for color reproduction and color space mapping of manuscript information obtained.Then,result from polynomial parameter equation and four-parameter log-logistic parameter equation,the printed photographic data is represented,and the printed matter is corrected with high fidelity according to gray balance algorithm,which solves the color deviation in the process of color reproduction.In addition,aiming at the metamerism data collected in the experiment,a mathematical model of grey component replacement(GCR)is established by using ridge regression algorithm.This model represents the maximum replacement range between CMY and K in metamerism data,and effectively solves the problem of the maximum proportion of metamerism data and GCR in specific tones,as well as common data problems such as color reproduction,spot color configuration and ink saving in the actual printing process.Finally,the optimal dynamic range of embedded watermark is studied.The image with the type of RGB is given,the C,M,Y(Cyan,Magenta,Yellow)parameters corresponding to metamerism can be solved by using the gradient descent method through custom K(carbon-containing ink)channel data.Then,the text,Logo,QR code and so on are employed as the content of K version information hiding image to design the spreading effect on different carrier images,and the specific experimental parameters are compared.In order to verify the effect of information hiding and printing anti-counterfeiting,the image quality evaluation index RMSE and linear regression coefficient R2 are used to evaluate the correction effect and information hiding.The experimental results show that the metamerism anti-counterfeiting image generated by model modulation with strong anti-duplication anti-counterfeiting characteristics,good anti-counterfeiting effect and more convenient information hiding method.In this thesis,metamerism information hiding is carried out in the maximum dynamic range by applying color space conversion technology,color correction,metamerism information modulation,information hiding,digital image processing and other technologies.It not only uses ordinary CMYK ink for information carrying and anti-counterfeiting,but also solves the common scientific problems of grey component replacement(GCR)based on metamerism.This technology can be effectively applied to the field of copyright protection of printed matter,and improve the security quality and anti-counterfeiting effect of information.