MOISTURE SENSOR AND WINDSHIELD FOG DETECTOR

• US 20070194208A1
• Filed: 03/29/2007
• Published: 08/23/2007
• Est. Priority Date: 09/16/1997
• Status: Active Grant

• Current Assignee: Gentex Corporation
• Original Assignee: Gentex Corporation
• Inventors: Roberts, John, Stam, Joseph, Bechtel, Jon
• Granted Patent: US 7,485,844 B2
• Time in Patent Office: Days
• US Class Current: 250/208.1
• CPC Class Codes: B60S 1/0822 characterized by the arrangement or type of detection means
• CPC Class Codes: B60S 1/0833 Optical rain sensor
• CPC Class Codes: B60S 1/0844 including a camera
• CPC Class Codes: B60S 1/0885 the sensor being integrated in a rear-view mirror module
• CPC Class Codes: B60S 1/0888 characterized by the attachment of the elements in a unit
• CPC Class Codes: G06T 2207/20056 Discrete and fast Fourier transform, [DFT, FFT]
• CPC Class Codes: G06T 2207/30252 Vehicle exterior; Vicinity of vehicle
• CPC Class Codes: G06T 7/42 using transform domain methods
• CPC Class Codes: G06V 20/56 exterior to a vehicle by using sensors mounted on the vehicle
• CPC Class Codes: H04N 23/00 Cameras or camera modules comprising electronic image sensors; Control thereof
• CPC Class Codes: Y10S 15/15 Moisture responsive
• CPC Class Codes: Y10S 318/02 Windshield wiper controls

Abstract

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 which represents the illumination level is converted to a corresponding gray scale value by an analog digital converter. 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.

Claims

1. A system for detecting moisture on a vehicle windshield comprising:

an image sensor having an imaging surface, said image sensor mounted in said vehicle such that said imaging surface is inclined with respect to vertical;

an optical system operative to image at least a portion of the vehicle windshield onto the image sensor; and

a processing system in communication with the image sensor and operative to analyze images from the image sensor to detect moisture.