Spectrum-controlled LED system for light quality testing

A light emitting diode (LED) light source based on Red, Green, Blue (RGB) LEDs is capable of producing high quality white light, albeit with unstable color properties. In this paper, we present a computer-controlled light viewing box which was designed and built to create an environment for RGB-based LED lighting quality investigation. The system contains RGB LEDs, the intensity of which can be controlled individually, lending control over the spectrum in the viewing box. The system is used to test the quality of an RGB-based white light, the spectrum of which is optimized based on its tristimulus values compared with the commonly used CIE reference illuminant-D65. It computes chromaticity coordinates and the key quality indices including the color error of the light source. Using a psychophysical test, the optimized white light is tested for its naturalness, attractiveness, brightness and preference compared to a standard white LED light source.