A Fast and Accurate Light Reflection Model
		Introduction
		Physical Parameters

Geometrical Parameters

The geometry of light reflection at a surface is illustrated in Figure 2. The polar and azimuthal angles of incidence and reflection are given by (θ_i,φ_i) and (θ_r,φ_r), respectively, and the solid angle of the incident light is given by dω_i. The polar angles are measured from the surface normal. For isotropic surfaces, the BRDF is independent of φ_i because of rotational symmetry.

Figure 2: Geometry of incident and reflected light

We can express the incident energy flux dE_i in terms of the incident radiance I_i, the incident angle θ_i and the incident solid angle dθ_i

dEi = Ii • cosθi • dωi

(2)

 

Last modified: Mon Sep 5 22:07:26 EDT 2011