05923027 is referenced by 420 patents and cites 17 patents.

A control system 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 on to an image array sensor, 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. The gray scale values corresponding to the image are stored in memory. 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 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 as well as the exterior of the windshield. By providing a system for automatically detecting the presence of fog on the interior and exterior of the windshield, serious performance limitations of known automatic rain sensors are eliminated.

Title
Moisture sensor and windshield fog detector using an image sensor
Application Number
8/931118
Publication Number
5923027
Application Date
September 16, 1997
Publication Date
July 13, 1999
Inventor
John K Roberts
East Grand Rapids
MI, US
Jon H Bechtel
Holland
MI, US
Joseph S Stam
Holland
MI, US
Agent
Brooks & Kushman P C
Assignee
Gentex Corporation
MI, US
IPC
B60S 1/08
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