Optical sensor for use in windscreen of car, is designed such that transmitting power to received power ratio is intermittently calibrated, permeability of optical passage window is measured and evaluation of visual range is considered

摘要

The sensor (110) is designed such that transmitting power to received power ratio is intermittently calibrated for actual visual range measurements, permeability of an optical passage window is measured and evaluation of a visual range is considered. The sensor performs the visual range measurements by evaluation of a pulse shape and amplitude of signals backscattered by a visual range coercive medium. Vehicle speed and vehicle density on a road (114) are measured and registered in addition to measurement of the visual range.