Vehicle rain sensor using imaging sensor

• US 6,320,176 B1
• Filed: 06/22/2000
• Issued: 11/20/2001
• Est. Priority Date: 02/26/1993
• Status: Expired due to Fees

• Current Assignee: Donnelly Corporation (Magna International Incorporated)
• Original Assignee: Donnelly Corporation (Magna International Incorporated)
• Inventors: Schofield, Kenneth, Vadas, Keith J., Larson, Mark L.
• Primary Examiner(s): Lee, John R.
• Application Number:
  US09/599,979
• Time in Patent Office: 516 Days
• Field of Search: 250/573, 250/574, 250/208.1, 250/559.4, 250/559.41, 356/338, 356/343, 356/436, 356/445, 356/446, 356/237.3
• US Class Current: 250/208.1
• CPC Class Codes: B60N 2/002 Seats provided with an occupancy detection means mounted therein or thereon detection means responsive to presence or absence of children B60N2/266
• CPC Class Codes: B60Q 1/085 due to special conditions, e.g. adverse weather, type of road, badly illuminated road signs or potential dangers B60Q1/10, B60Q1/12, B60Q1/1423 take precedence
• CPC Class Codes: B60Q 1/14 having dimming means
• CPC Class Codes: B60Q 1/1423 Automatic dimming circuits, i.e. switching between high beam and low beam due to change of ambient light or light level in road traffic
• CPC Class Codes: B60Q 1/18 being additional front lights bracket mounted headlights B60Q1/0483
• CPC Class Codes: B60Q 2300/054 Variable non-standard intensity, i.e. emission of various beam intensities different from standard intensities, e.g. continuous or stepped transitions of intensity
• CPC Class Codes: B60Q 2300/056 Special anti-blinding beams, e.g. a standard beam is chopped or moved in order not to blind
• CPC Class Codes: B60Q 2300/112 Vehicle speed
• CPC Class Codes: B60Q 2300/122 Steering angle
• CPC Class Codes: B60Q 2300/21 Manual control
• CPC Class Codes: B60Q 2300/312 Adverse weather
• CPC Class Codes: B60Q 2300/314 Ambient light
• CPC Class Codes: B60Q 2300/332 on city roads
• CPC Class Codes: B60Q 2300/3321 Detection of streetlights
• CPC Class Codes: B60Q 2300/41 preceding vehicle
• CPC Class Codes: B60Q 2300/42 oncoming vehicle
• CPC Class Codes: B60Q 9/008 for anti-collision purposes
• CPC Class Codes: B60R 1/088 using a cell of electrically changeable optical characteristic, e.g. liquid-crystal or electrochromic mirrors
• CPC Class Codes: B60R 1/12 Mirror assemblies combined with other articles, e.g. clocks
• CPC Class Codes: B60R 11/04 Mounting of cameras operative during drive; Arrangement of controls thereof relative to the vehicle
• CPC Class Codes: B60R 2001/1223 : with sensors or transducers
• CPC Class Codes: B60R 2001/1253 : with cameras, video cameras or video screens
• CPC Class Codes: B60R 21/01538 : for image processing, e.g. cameras or sensor arrays
• CPC Class Codes: B60S 1/0822 : characterized by the arrangement or type of detection means
• 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: G06V 10/141 : Control of illumination
• CPC Class Codes: G06V 10/143 : Sensing or illuminating at different wavelengths
• CPC Class Codes: G06V 20/584 : of vehicle lights or traffic lights
• CPC Class Codes: H04N 23/45 : for generating image signals from two or more image sensors being of different type or operating in different modes, e.g. with a CMOS sensor for moving images in combination with a charge-coupled device [CCD] for still images
• CPC Class Codes: H04N 7/181 : for receiving images from a plurality of remote sources

Abstract

A vehicular rain sensor which senses precipitation at a vehicle window. The rain sensor comprises an imaging array sensor and a control. The imaging array sensor is directed at the vehicle window from inside the vehicle and comprises a camera device capable of imaging precipitation at a surface of the window. The camera is operable to image the precipitation at least in response to ambient light present at the window. The control responds to an output of the imaging array sensor in order to indicate precipitation at the surface of the window. The control determines the presence of precipitation via spatial filtering of the image received by the camera device.

Claims

1. A vehicular rain sensor which senses precipitation at a vehicle window, said vehicular sensor comprising:

an imaging array sensor directed at the vehicle window from inside the vehicle, said imaging array sensor comprising a camera device capable of imaging precipitation at a surface of the vehicle window, said camera imaging precipitation in response to ambient light present at the window; and

a control which responds to an output of said imaging array sensor in order to indicate precipitation at a surface of the window.

2. The vehicular rain sensor in claim 1, wherein the surface of the window is an exterior surface exposed to weather conditions and the precipitation indicated is rain.

3. The vehicular rain sensor of claim 1, wherein said imaging array sensor is directed forwardly with respect to the vehicle, the window being a windshield of the vehicle.

4. The vehicular rain sensor in claim 3, wherein said control is adapted to be positioned substantially adjacent a rear view mirror housing.

5. The vehicular rain sensor of claim 1, wherein said control is further operable to control a windshield wiper on the vehicle in response to indication of precipitation at the window.

6. The vehicular rain sensor of claim 5, wherein said control is operable to activate and deactivate the windshield wiper and to establish a frequency of intermittent operation in response to indication of precipitation at the window.

7. The vehicular rain sensor of claim 1, wherein said imaging array sensor comprises a pixelated array sensor comprising a plurality of pixels.

8. The vehicular rain sensor in claim 7, wherein said imaging array sensor is a CMOS sensor.

9. The vehicular rain sensor of claim 7, wherein said control is operable to indicate precipitation at the window via spatial filtering of said pixels.

10. The vehicular rain sensor of claim 9, wherein the spatial filtering includes statistical analysis of at least one targeted pixel of said plurality of pixels with respect to adjacent pixels.

11. The vehicular rain sensor of claim 10, wherein the statistical analysis determines a lack of continuous variation of differences between the targeted pixel and adjacent pixels.

12. The vehicular rain sensor of claim 11, wherein the lack of continuous variation of differences between the targeted and adjacent pixels is determined via determination of a change in a first derivative of said plurality of pixels.

13. The vehicular rain sensor of claim 12, wherein said control is operable to determine the first derivative of said pixels by determining a level of one of entropy and disarray of said pixels with respect to at least one adjacent pixel.

14. The vehicular rain sensor of claim 13, wherein said control is operable to determine the first derivative of each of said pixels via the following equation:

$\frac{<br><br>\left(P_i\right)}{<br><br>\mathrm{xy}}=\frac{\sqrt{\underset{j=1}{\overset{n}{\sum <br><br>}}<br><br>{\left(P_i-P_j\right)}^2}}{N};<br><br>$

where N is a quantity of neighboring pixels, P_j is one of the neighboring pixels, and P_i is the targeted one of said pixels.

15. The vehicular rain sensor of claim 14, wherein N is 8 and P_j is one of eight pixels adjacent to the targeted pixel.

16. A vehicular rain sensor which senses precipitation at a windshield of a vehicle, said vehicular sensor comprising:

an imaging array sensor directed forwardly with respect to the vehicle and at the vehicle windshield, said imaging array sensor comprising a camera device comprising a pixelated array sensor comprising a plurality of pixels, said camera device being operable to capture an image of precipitation at a surface of the windshield in response to ambient light at the windshield; and

a control which responds to an output of said imaging array sensor in order to indicate precipitation at a surface of the windshield via spatial filtering of said pixels, said control being further operable to control a windshield wiper on the vehicle in response to indication of precipitation at the windshield.

17. The vehicular rain sensor of claim 16, wherein said imaging array sensor comprises a CMOS sensor.

18. The vehicular rain sensor of claim 16, wherein the spatial filtering includes statistical analysis of at least one targeted pixel of said plurality of pixels with respect to adjacent pixels to determine a lack of continuous variation of differences between the targeted pixel and adjacent pixels.

19. The vehicular rain sensor of claim 18, wherein the lack of continuous variation of differences between the targeted and adjacent pixels is determined via determination of a change in a first derivative of said plurality of pixels, said control being operable to determine the first derivative of said pixels by determining a level of one of entropy and disarray of said pixels with respect to at least one adjacent pixel.

20. The vehicular rain sensor of claim 16, wherein said control is operable to activate and deactivate the windshield wiper and to establish a frequency of intermittent operation in response to indication of precipitation at the windshield.

21. A vehicular rain sensor which senses precipitation at a windshield of a vehicle, said vehicular sensor comprising:

an imaging array sensor directed forwardly with respect to the vehicle and at the vehicle windshield, said imaging array sensor comprising a CMOS sensor operable to capture an image of precipitation at the windshield in response to ambient light present at the windshield; and

a control which responds to an output of said imaging array sensor in order to indicate precipitation at a surface of the windshield, said control being further operable to control a windshield wiper on the vehicle in response to indication of precipitation at the windshield.

22. The vehicular rain sensor of claim 21, wherein said control is operable to activate and deactivate the windshield wiper and to establish a frequency of intermittent operation in response to indication of precipitation at the windshield.

23. The vehicular rain sensor of claim 21, wherein said CMOS sensor comprises a plurality of pixels, said control being operable to indicate precipitation at the windshield via spatial filtering of said pixels.

24. The vehicular rain sensor of claim 23, wherein the spatial filtering includes statistical analysis of at least one targeted pixel of said plurality of pixels with respect to adjacent pixels to determine a lack of continuous variation of differences between the targeted pixel and adjacent pixels.