Multispectral systems allow the spectral characterization of the scene through several acquisition channels with different spectral features. The spectral sampling can be done by using transmittance filters and a white light source or illuminating the scene using light sources with different spectral emission characteristics. Light-emitting diodes based light sources have started to be used in multispectral systems, mainly to develop low-cost devices for the industry. In this study we analyze the spectral power distribution and color variability of white and single color light-emitting diodes relative to the viewing angle, and highlight some aspects that must be taken into account if these light sources want to be used in a multispectral system.
Óscar Martínez, Meritxell Vilaseca, Carles Pizarro, Èdgar Ferrer, Montserrat Arjona, Jaume Pujol, "Spectral Variability of Light-Emitting Diodes with Angle" in Proc. IS&T CGIV 2010/MCS'10 5th European Conf. on Colour in Graphics, Imaging, and Vision 12th Int'l Symp. on Multispectral Colour Science, 2010, pp 547 - 553, https://doi.org/10.2352/CGIV.2010.5.1.art00085