Comparison of microfacet BRDF model elements to diffraction BRDF model elements

摘要

A popular class of BRDF models is the microfacet model, where geometric optics is assumed, but where physical optics effects such as accurate wavelength scaling, important to Hyperspectral Imagery, are lost. More complex physical optics models may more accurately predict the BRDF, but the calculation is time-consuming. These seemingly disparate approaches are compared in detail. The linear systems direction cosine space is compared to microfacet coordinates, and the microfacet models Fresnel reflection in microfacet coordinates is compared to diffraction theory's Fresnel-like term. Similarities and differences between these terms are highlighted to merge these two approaches to the BRDF.