Optimizing color matching in a lighting reproduction system for complex subject and illuminant spectra

Abstract

This paper presents a technique for improving color matching results in an LED-based lighting reproduction system for complex light source spectra. In our technique, we use measurements of the spectral response curve of the camera system as well as one or more spectral reflectance measurements of the illuminated object to optimize the color matching. We demonstrate our technique using two LED-based light sources: an off-the-shelf 3-channel RGB LED light source and a custom-built 9-channel multi-spectral LED light source. We use our technique to reproduce complex lighting spectra including both fluorescent and tungsten illumination using a Macbeth color checker chart and a human face as test subjects. We show that by using knowledge of the camera spectral response and/or the spectral reflectance of the subjects that we can significantly improve the accuracy of the color matching using either the 3-channel or the 9-channel light, achieving acceptable matches for the 3-channel source and very close matches for the multi-spectral 9-channel source.