Experimental measurement and analysis of wavelength-dependent properties of the BRDF
Samuel D. Butler, Stephen E. Nauyoks, Michael A. Marciniak · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2015
The microfacet BRDF model is preferred to describe reflectance in many applications due to its closed-form approximation to the BRDF which is relatively easy to use; however, it almost entirely excludes wavelength-dependent scaling of the reflectance distribution. To rectify this, the BRDF was measured at multiple incident angles and for multiple materials at several wavelengths between 3.39 μm and 10.6 μm. Results quantify the dramatic change in the specular BRDF of a variety of materials even after accounting for overall reflectance, and suggests it is necessary to modify the wavelength dependence in the microfacet model.