ABSTRACT

Recently, Ohno proposed a method for computing the correlated color temperature (CCT) of a light source and the shortest distance (with sign) between its chromaticity and that of the Planckian locus (D_uv). In Ohno’s method, firstly a lookup table is chosen, and then a hybrid method based on the triangular and parabolic solutions is used to predict the CCT and D_uv of a given light source. In this article, we found that spline interpolation is better than the parabolic solution for predicting CCT and D_uv. Therefore, we propose two new hybrid methods based on the triangular and either spline interpolation or third-order interpolation using two local function values and two local second-order derivative values. Comprehensive tests using the lookup table with both 1% and 0.25% increments relative to the current selected color temperature demonstrate that the proposed methods outperform Ohno’s method.

摘要

最近，大野提出了一种计算光源相关色温（CCT）及其色度与普朗克轨迹（D _uv）色度之间的最短距离（带符号）的方法。在 Ohno 的方法中，首先选择一个查找表，然后使用基于三角和抛物线解的混合方法来预测给定光源的 CCT 和D _{uv 。}在本文中，我们发现样条插值在预测 CCT 和D _uv方面优于抛物线解. 因此，我们提出了两种新的基于三角和样条插值或三阶插值的混合方法，使用两个局部函数值和两个局部二阶导数值。使用相对于当前选定色温有 1% 和 0.25% 增量的查找表的综合测试表明，所提出的方法优于 Ohno 的方法。