Incorporating the BRDF into an infrared scene generation system

The directional characteristics of surface emittance and reflectance have a significant impact on the radiance of a target. The directional characteristics of a surface are completely specified by the bidirectional reflectance distribution function (BRDF). In this paper a practical implementation of a method for calculating directional reflection and emission using the BRDF for the purpose of simulating infrared scenes is described. The implementation is based on the existing Georgia Tech Infrared Signature Code (GTSIG) and the semi-empirical Sandford-Robeitson BRDF model.