A control system is disclosed for automatically detecting moisture on the windshield of a vehicle. The automatic moisture detecting system includes an optical system for imaging a portion of the windshield onto an image array sensor, such as a CMOS active pixel sensor. The voltage of each of the pixels...http://www.google.com.au/patents/US6946639?utm_source=gb-gplus-sharePatent US6946639 - Moisture sensor and windshield fog detector
