Florica Mindru Luc J. Van Gool Theo Moons Model Estimation for Photometric Changes of Outdoor Planar Color Surfaces Caused by Changes in Illumination and Viewpoint. 620-623 2002 ICPR (1) http://doi.ieeecomputersociety.org/10.1109/ICPR.2002.1044819 db/conf/icpr/icpr2002-1.html#MindruGM02