Effective directional reflectance modelling of fine-structured surfaces

An additive superposition approach is presented to model the effective directional surface reflectance of optically rough fine-textured planar surfaces. As examples, effective reflectance models for randomly droplet-occupied surfaces and for periodic two-dimensional sawtooth-like fine-structured surfaces are constructed and parameterised. Comparative ray-optical simulation results confirm the applicability of the approach to effective reflectance models of optically rough, finely structured surfaces.