MOISTURE SENSOR UTILIZING STEREO IMAGING WITH AN IMAGE SENSOR

• US 20030066948A1
• Filed: 10/04/2001
• Published: 04/10/2003
• Est. Priority Date: 10/04/2001
• Status: Active Grant

• Current Assignee: Gentex Corporation
• Original Assignee: Gentex Corporation
• Inventors: Roberts, John K., Ockerse, Harold C.
• Granted Patent: US 6,617,564 B2
• Time in Patent Office: Days
• US Class Current: 250/208.1
• CPC Class Codes: B60S 1/0818 including control systems responsive to external conditions, e.g. by detection of moisture, dirt or the like
• 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: G06T 2207/30268 Vehicle interior
• CPC Class Codes: G06T 7/0002 Inspection of images, e.g. flaw detection
• CPC Class Codes: G06T 7/97 Determining parameters from multiple pictures depth or shape recovery from multiple images G06T7/55; stereo camera calibration G06T7/85
• CPC Class Codes: G06V 20/56 exterior to a vehicle by using sensors mounted on the vehicle
• CPC Class Codes: H04N 13/161 Encoding, multiplexing or demultiplexing different image signal components for multi-view video sequence encoding H04N19/597
• CPC Class Codes: H04N 13/218 using spatial multiplexing
• CPC Class Codes: H04N 13/254 in combination with electromagnetic radiation sources for illuminating objects
• CPC Class Codes: H04N 13/257 Colour aspects
• CPC Class Codes: H04N 13/296 Synchronisation thereof; Control thereof
• CPC Class Codes: H04N 2013/0081 Depth or disparity estimation from stereoscopic image signals
• CPC Class Codes: H04N 23/811 by dust removal, e.g. from surfaces of the image sensor or processing of the image signal output by the electronic image sensor
• CPC Class Codes: Y10S 318/02 Windshield wiper controls

Abstract

A moisture sensing system of the present invention includes first and second sensor arrays, at least one optical system operative to image the same portion of the surface onto both of the sensor arrays, and a processing system in communication with the sensor arrays and operative to analyze images from the sensor arrays to detect moisture. The sensor arrays may be two-dimensional sensor arrays that are separate or different portions of the same sensor array. This system may be used to control the windshield wipers of a vehicle. The processing system may be configured to subtract an image obtained from the first sensor array from an image obtained from the second sensor array to distinguish between near field and far field objects.

Claims

1. A system for detecting moisture on a surface comprising:

a sensor array having first and second portions;

at least one optical system operative to image the same portion of the surface onto both of said portions of said sensor array; and

a processing system in communication with said sensor array and operative to analyze images from said first and second portions of said sensor array to detect moisture.

2. The system of claim 1, wherein said processing system is configured to detect edges of the images from said image sensor array portions.

3. The system of claim 2, wherein said processing system is further configured to compare the relative position of edges detected in an image from said first portion of said sensor array with the relative position of edges detected in an image from said second portion of said sensor array to distinguish objects on the surface from far field objects.

4. The system of claim 1, wherein said processing system is configured to compare the relative position of objects in an image from said first portion of said sensor array with the relative position of objects in an image from said second portion of said sensor array to distinguish objects on the surface from far field objects.

5. The system of claim 1, wherein said processing system is configured to digitize and subtract images from said first and second portions of said sensor arrays to distinguish objects on the surface from far field objects.

6. The system of claim 1, wherein said first and second portions of said sensor array are vertically offset from one another.

7. The system of claim 1 and further including a rearview mirror assembly, wherein said sensor array is supported on said rearview mirror assembly.

8. The system of claim 1 and further including a rearview mirror assembly, wherein at least a portion of said processing system is supported on said rearview mirror assembly.

9. The system of claim 1, wherein said processing system reads image data from at least one row but less than all rows of said first portion of said sensor array and image data from corresponding row(s) of said second portion of said sensor array, compares the image data read, and stores the result of the comparison prior to reading image data from additional rows of said first and second portions of said sensor array.

10. The system of claim 1, wherein said first and second portions of said sensor array are two-dimensional arrays.

11. The system of claim 1, wherein said first and second portions of said sensor array acquire data simultaneously.

12. A system for detecting moisture on a surface comprising:

first and second sensor arrays spatially offset from one another;

at least one optical system operative to image the same portion of the surface onto both of said sensor arrays; and

a processing system in communication with said sensor arrays and operative to analyze images from said sensor arrays to detect moisture, wherein said processing system reads image data from at least one row but less than all rows of said first sensor array and image data from corresponding row(s) of said second sensor array, compares the image data read, and stores the result of the comparison prior to reading image data from additional rows of said sensor arrays.

13. The system of claim 12, wherein said processing system is configured to detect edges of the images from said image sensor arrays.

14. The system of claim 12, wherein said first and second sensor arrays are two-dimensional arrays.

15. The system of claim 12, wherein said first and second sensor arrays are portions of two separate image sensor.

16. The system of claim 12, wherein said first and second sensor arrays are two different portions of the same image sensor.

17. The system of claim 12, wherein said first and second sensor arrays are vertically offset from one another.

18. The system of claim 12 and further including a rearview mirror assembly, wherein said first and second sensor arrays are supported on said rearview mirror assembly.

19. A method of detecting moisture on a surface comprising the steps of:

obtaining two two-dimensional images of the same portion of the surface from two different angles;

digitizing the two images; and

subtracting the two digitized images from one another to thereby remove far field objects from a resultant image while leaving information relating to near field objects in the resultant image, wherein the near field objects correspond to moisture on the surface.

20. A windshield wiper control system for a vehicle comprising:

first and second two-dimensional image sensors;

an optical system operative to image the same portion of the surface of the vehicle windshield onto said first and second image sensors; and

a processing circuit in communication with said image sensors and operative to analyze images from said image sensors to detect moisture on the windshield and to activate the windshield wipers when moisture is detected.

21. The system of claim 20, wherein said processing circuit is configured to detect edges in the images from said image sensors.

22. The system of claim 20, wherein said processing circuit is further configured to compare the relative position of edges detected in an image from said first image sensor with the relative position of edges detected in an image from said second image sensor to distinguish objects on the surface from far field objects.

23. The system of claim 20, wherein said processing circuit is configured to compare the relative position of objects in an image from said first image sensor with the relative position of objects in an image from said second image sensor to distinguish objects on the surface from far field objects.

24. The system of claim 20, wherein said processing circuit is configured to digitize and subtract the images from said first and second image sensors to distinguish objects on the surface from far field objects.

25. The system of claim 20, wherein said first and second image sensors are two adjacent portions of the same image sensor device.

26. The system of claim 20, wherein said first and second image sensors are portions of two separate image sensor devices.

27. The system of claim 20 and further including a rearview mirror assembly, wherein said image sensor arrays are supported on said rearview mirror assembly.

28. The system of claim 20 and further including a rearview mirror assembly, wherein at least a portion of said processing circuit is supported on said rearview mirror assembly.

30. A system for use in a controlled vehicle comprising:

an optical system including an array of sensors; and

a processing subsystem in communication with said sensors for sensing moisture on a windshield of the controlled vehicle and for detecting lights of vehicles generally in front of the controlled vehicle and controlling exterior lights of the controlled vehicle, wherein said processing subsystem disables activation of high beam headlamps of the controlled vehicle when moisture is detected on the vehicle windshield.

31. The system of claim 30, wherein the processing subsystem includes a microprocessor coupled to both an exterior light control circuit and a windshield wiper control circuit of the controlled vehicle.

32. The system of claim 30, wherein said processing subsystem does not attempt to detect lights of vehicles generally in front of the controlled vehicle when moisture is sensed on the windshield.

33. The system of claim 30, wherein said processing subsystem activates low beam headlamps of the controlled vehicle when moisture is sensed on the windshield.

34. A system for use in a controlled vehicle comprising:

an optical system including two arrays of sensors and a red filter for filtering all but red light from light projected onto one of the two sensor arrays;

a light source for projecting red light onto a windshield of the controlled vehicle; and

a processing subsystem in communication with said sensors for sensing moisture on the windshield of the controlled vehicle.

35. The system of claim 34, wherein said optical system includes two lenses, each lens focusing light from the same region on the windshield onto a different one of said arrays of sensors.

36. The system of claim 34, wherein said two sensor arrays are different regions of a larger array of sensors.

37. The system of claim 34, wherein said processing subsystem detects lights of vehicles generally in front of the controlled vehicle and controls exterior lights of the controlled vehicle.

38. The system of claim 37, wherein said processing subsystem disables activation of high beam headlamps of the controlled vehicle when moisture is detected on the vehicle windshield.