This activity stems from the need to enhance visibility of certain icons on the central console when these directly illuminated by sunlight. Originally, the research had focussed on studying the optical behaviour of the surfaces of the materials used inside the vehicle in order to develop an experimentally-validated predictive mathematical model; the final output was correlated with icon contrast against the background in daylight driving conditions. The activity is focussed on studying the physics of the diffusion of light: a mathematical model based on BRDF (Bidirectional Reflectance Distribution Function) definition has been developed in order to obtain a complete description of the behaviour of light diffused by a rough surface, according to characteristic physical parameters (such as roughness and the intrinsic diffusion properties of the material). Initially, this output was linked to a model of the capacity of human sight to perceive stimuli of different intensity in order to define the geometric conditions of low contrast. The results have been confirmed by direct measurements of BRDF. Further developments have resulted in application of the outputs of the diffusion model to virtual analysis in the field of “Visual Ergonomics”.