New method of color rendering evaluation of illuminants

　　Color rendering is one of the important features to develop good light sources. It is time-consuming and costs a lot, however, to make actual light sources having various spectral power distribution in order to test its color rendering performance. It will be helpful if one can simulate how colors will be rendered under certain light source having arbitrary spectral power distribution on a visual display terminal. Multispectral camera will help making such simulator because it can measure spectral reflectance of any scene pixel by pixel, thereby enables to calculate tristimulus values of the scene under any light sources by which an image can be reproduced on a calibrated monitor. In this study, we developed a system of color rendering simulator that can simulate color-rendering properties of light sources having arbitrary spectral power distribution.
　　Recently, white LED light sources begin to spread as new illuminant. Its color-rendering features are usually evaluated by the CIE method, but it sometimes fails to describe its visual impression. We applied this color-rendering simulator to evaluate color-rendering features of white LED light sources. Purposes of this study are, first, to optimize spectral power distribution of white LED in terms of color rendering, and second, to test if the CIE color rendering indices work properly to describe visual impression for such illuminants.