Probabilistic water BRDF model

Is a reflecting surface, and therefore can be a hazard source when illuminated by a laser beam. The extent of the hazard has been a matter of concern on a regular basis over the years, with disallowing interactions of laser beams with water being the most conservative approach. Quantifying the actual hazard requires a bi-directional reflectance distribution (BRDF) model of the water surface, and it is probabilistic due to the nature of water surfaces. The surface of water has reflecting features over many length scales, from small ripples to large swells. These wave features depend on the wind speed, and their variability obviously complicates a BRDF model. A combination of models, one for small-scale features and another for large-scale, provides the basis for a probabilistic water BRDF. This presentation describes the components of the model and illustrates dependencies on wind speed and direction, laser beam diameter, and angles of incidence and reflection.