Modeling of light scattering by rough surfaces with relevance to pavements monitoring sensors

A physical interpretation of reflectance data, for applications related to lighting, or pavements monitoring systems, relies on the development of models describing the interactions between light and the media under study. Beyond ray-tracing approaches, the general radiation transport theory allows a neat solution to the problem of rough surfaces, provided distinctive features originating in the back-scattering behavior and opposition effect, are accurately accounted for. The present model takes advantage of analytical expressions for the once-scattered part of the reflectance, and computes multiply scattered contribution via a successive order scattering approach. A sensitivity analysis is conducted to assess the influence of parameters controlling the scattering processes and opposition effect. Finally, model outputs are confronted with actual laboratory measurements, and basis to evaluate surface roughness from reflectance data are suggested.