Windscreen rain drop detection system uses autocorrelation analysis of video image contrast distribution to distinguish obscuration type and start suitable clearing action

摘要

A windscreen rain drop detection system (5) has a video detector (6) focussed (8) on the surface (9a) of the windscreen (9) to determine the image contrast distribution (11) and autocorrelation function in part of a section through the surface and compare it (7) with predetermined data to detect rain drops and distinguish (12) other types of obscuration.