Soiling and/or deterioration of automobile glazing causes stray light by transmission or reflection. Stray light impairs the driver's environmental perception. The level of perception interference depends strongly on the stray light characteristic. Wide-angle diffusion (angle of deflection over 2 degrees) is especially discussed. Following some practical remarks, the possibility of characterizing the stray object by means of characteristic parameters is discussed. Some quantitative relations based on a theoretical treatment of the problem are given. The principles of two systems for measurement and analysis of diffusion characteristic are presented together with some typical results. One system uses stationary equipment which is based on the scanning principle. The other instrument involved is a mobile probe for stray light which is used directly on the vehicle.
Samenvatting