Incorporating subsurface attenuation into the Beckmann model

In this paper we explore whether the Fresnel term can be used to improve the predictions of the Beckmann-Kirchhoff (B-K) model for moderately-rough surfaces. Our arm in developing this model is to describe subsurface scattering effects for surfaces of intermediate roughness. We use the BRDF measurements from the CUReT database to compare the predictions of the Fresnel correction process with several variants of the B-K model and the Oren and Nayar Model. The study reveals that our new Fresnel correction provides accurate predictions, which are considerably better than those achieved using both the alternative variants of the B-K model and the Oren-Nayar model.