MOISTURE SENSOR AND WINDSHIELD FOG DETECTOR

摘要

A control system (20) for automatically detecting moisture on the windshield (26) of a vehicle. The automatic moisture detecting system (20) includes an optical system (30) for imaging a portion of the windshield (26) onto an image array sensor (32), such as a CMOS active pixel sensor. The voltages of each of the pixels which represents the illumination level is converted to a corresponding gray scale value by an analog digital converter (35). The gray scale values correspondi ng to the image are stored in memory (38). The spatial frequency composition of the gray scale values are analyzed to determine the amount of rain present. In order to provide a control signal to control the operation of the windshield wipers (40) of the vehicle as a function of the amount of moisture present. The system is also adapted to detect the level of fog both on the interior of the windshield (2 6) as well as the exterior of the windshield (26). By providing a system for automatically detecting the presence of fog on the interior and exterior of the windshield (26), serious performance limitations of known automatic rain sensors are eliminated.