Statistical approach to color rendition properties of solid state light sources

Versatile spectral power distribution of solid-state light sources offers vast possibilities in color rendition engineering. The optimization of such sources requires the development and psychophysical validation of an advanced metric for assessing their color quality. Here we report on the application and validation of the recently introduced statistical approach to color quality of illumination. This new metric uses the computational grouping of a large number of test color samples depending on the magnitude and direction of color-shift vectors in respect of just perceived differences of chromaticity and luminance. This approach introduces single-format statistical color rendition indices, such as Color Fidelity Index, Color Saturation Index and Color Dulling Index, which are the percentages of test color samples with particular behavior of the color-shift vectors. The new metric has been used for the classification of practical phosphor conversion white light-emitting diodes (LEDs) and polychromatic LED clusters into several distinct categories, such as high-fidelity, color saturating, and color dulling light sources. We also report on the development of the tetrachromatic light source with dynamically tailored color rendition properties and using this source for the psychophysical validation of the statistical metric and finding subjective preferences to the color quality of lighting.