Analytical BRDF model for rough surfaces

A new analytical reflectance distribution model for rough surfaces is presented. The model is based on geometrical optics and assumes that the rough surface consist of small, mirror-like facets. Predicted reflectance distribution function depends on incident angle, surface's roughness, and reflection coefficient, i.e. a function of wavelength. The effect of multiple scattering is included in the analysis. The model also takes into account the influence of shadowing and masking effects. The angular distributions of reflectance predicted by the analysis successfully predict the off-specular maxima in the reflection distribution which emerge as the incidence angle increases.