Research On Color Characterization For Inkjet Printer Based On YNSN Model

Spectral-based color reproduction offers many advantages, such as minimizing themetamerism, realizing the high fidelity. In recent years, spectral-based printercharacterization has caused wide attention of scholars. In this research, the spectralYule-Nielsen modified Murray-Davies model and YNSN model were used tocharacterize Epson Stylus Pro7880C inkjet printer.First of all, the spectral Yule-Nielsen modified Murray-Davies model was used toanalyze the CMYK ramps printed. The optimized Yule-Nielsen n facter value, whichminimized the average colorimetric differences under different illuminants and the averagesRMS between the measured and the estimated, was determined. The one-dimensionallook-up tables between the theoretical colorant values and the effective colorant values forCMYK ramps(LUTs) were established by the least square fitting method. The CMYKoverprinted training sample was then designed and the forward YNSN model was established.The prediction accuracy of forward YNSN model was evaluated for various Yule-Nielsen nfactor values and the optimized n value was also to be found. The CMYK overprinted testsample was then designed to evaluate the performance of optimized forward YNSN model.Experimental results showed that the optimized n factor values which minimized sRMS andthe colorimetric differences under different illuminants for the spectral Yule-Nielsenmodified Murray-Davies model were about1.0-1.1. The optimized n factor value for theforward YNSN model was about0.9. At this moment, the average color differences under A,D50and D65illuminants were almost between3-4, and the average sRMS was0.018. That isto say, the forward YNSN model had showed very good results for the inkjet printer.Because the backward model cannot be obtained by inversing the YNSN model directly,linear regression iteration(LRI), constrained minimization routine(CMR) and weightinversion(WI) were adopted instead in this research. The Macbeth ColorChecker testchart andthe designed CMYK overprinted testchart were used to evaluate the performance of the threeinversion methods. Experimental results showed that all the three inversion methods gavegood results for the designed CMYK overprinted testchart. The average sRMS of the threemethods were0.005,0.002and0.004respectively. And the average colorimetric differencesunder A, D50, D65illuminants were all below3. For the MacBeth ColorChecker testchart, theCMR method gave the best performance following by the LRI method and behind the WImethod.Finally, the main work and conclusions of this research were summarized, and the perspective of the future study was also forecasted.