Authors:
Olga E. Zheleznikova,Sergey V.Prytkov,Andrey M. Kokinov,DOI NO:
https://doi.org/10.26782/jmcms.spl.8/2020.04.00010Keywords:
Correlated color temperature,Planckianlocus,blackbodylocus,line of constant correlated temperature,chromaticity coordinates,absolute error,Abstract
Correlated color temperature (CCT) is a value that characterizes thechromaticity of radiation and it is also used for calculation of color rendering according to the metrics CRI and CQS and also in the theoretical researches. And if in the first case the specific accuracy is not required during its estimation because there are chromatic thresholds within the limits of which CCT is accepted to be the same, in the second and the third cases the accuracy of the methods cannot be neglected. Also, due to the fact that there are several methods of the CCT calculation, all of them possess different degree of complexity and accuracy and the researchers face the problem what method and in what case they shall prefer.The above mentioned determines the urgency of the studied problem. The objective of the article is to determine the distribution of the CCT absolute error in the field of its determination for the most well-known methods: Robertson’s method, Yoshi Ohno’s method, Javier Hernandez-Andres’ method, McCamy’s method. The leading approach to the research of this problem is to use the coordinates of chromaticity located on the lines of the constant correlated color temperature with the further evaluation of the absolute error as the initial data for the CCT calculation. As a result of the research it was revealed that the numerical methods of Robertson and Yoshi Ohno are significantly more precise than the analytical methods of Hernandez-Andres and McCamy in the whole CCT definition domain. On the base of the obtained distributions of the absolute error the recommendation can be given to use the different methods of calculation for different cases. The work compares the “classical” variant of Robertson’s method using the 31 isotherm and the variants with a bigger number of isotherms. It is shown that when the step between the isotherms is reducing the error is decreasing too. The developed method of estimation of the CCT calculation is universal and can be applied to other methods apart the methods considered in the article.Refference:
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