METHOD FOR DETECTING RAIN ON A WINDSCREEN

• US 20070267993A1
• Filed: 05/21/2007
• Published: 11/22/2007
• Est. Priority Date: 05/22/2006
• Status: Active Grant

• Current Assignee: Valeo Vision (Valeo SE)
• Original Assignee: Valeo Vision (Valeo SE)
• Inventors: Rebut, Julien, Bensrhair, Abdelaziz, Challita, Georges, Leleve, Joel
• Granted Patent: US 7,860,275 B2
• Time in Patent Office: Days
• US Class Current: 318/483
• 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: G01N 21/958 Inspecting transparent materials or objects, e.g. windscreens for conveyed flat sheet or rod G01N21/896
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/30248 Vehicle exterior or interior
• CPC Class Codes: G06T 7/44 using image operators, e.g. filters, edge density metrics or local histograms
• CPC Class Codes: G06V 10/46 Descriptors for shape, contour or point-related descriptors, e.g. scale invariant feature transform [SIFT] or bags of words [BoW]; Salient regional features colour feature extraction G06V10/56
• CPC Class Codes: G06V 20/56 exterior to a vehicle by using sensors mounted on the vehicle

Abstract

A method for detecting raindrops on a windscreen, which uses a camera, which is fitted inside the vehicle opposite the windscreen and which is focused at infinite. The method comprises steps of acquiring images by a camera through the windscreen, camera preferably focused at infinite, retrieving the contours of the spots present on the acquired images, and realizing the histogram of the widths of contours of the spots.

Claims

1. A method for detecting raindrops on a windscreen, wherein it uses a camera, which is fitted inside the vehicle opposite the windscreen and which is focused at infinite.

2. The method according to claim 1, wherein it uses the camera, which is also used to detect vehicles and/or roadside edges and/or to make the vehicle headlamps switch from one mode of lighting to another.

7. The method according to claim 1, wherein at least one of the stages (b to f) are implemented within the framework of a hierarchical approach.

8. A method according to claim 1, wherein said method further comprises the step of:

participating in automatic triggering or automatic modification of a functionality of the vehicle, more particularly actuation of the windscreen wipers, once the droplets of water have been detected on the windscreen.

11. The device according to claim 8, wherein the camera is shared with at least one other device equipping said vehicle.

12. The method according to claim 1 and further comprises the means of storing information, wherein said means memorizes one or more programs, the execution of which authorizes implementation of said method.

13. The method according to claim 1 and further comprises a computer program comprising means of storing information, comprising one or more sequences of executable instructions by a microprocessor and/or a computer, execution of said sequences of instructions authorizing implementation of said method.

3. A method for detecting raindrops on a windscreen, which comprises the steps of:

a stage (a) of acquiring images by a camera through the windscreen, camera preferably focused at infinite,

a stage (b) of retrieving contours of the spots present on the acquired images, and

a stage (c) of realizing a histogram of the widths of said contours of the spots.

4. The method according to claim 3, wherein said method further comprises the step of:

a stage (d) of thresholding, beyond a given minimum threshold, of the widths of contours of the spots, more particularly in order to confirm the possible presence of spots likely to correspond to droplets on the windscreen.

5. The method according to claim 4, wherein said method further comprises the step of:

a stage (e) of reconstructing the droplets based on the thresholded widths of contour.

6. The method according to claim 5, wherein said method further comprises the step of:

at least one stage (f) of characterizing the reconstructed spots, including at least one of the following measurements;

measure of variation of the greyscale in the spots, measure of blur of said spots, measure of shape of said spots, count of the number of spots.

9. A device for detecting raindrops on a windscreen, which comprises a camera fitted inside the vehicle, which is opposite the windscreen and which is focused at infinite.

10. A device for detecting raindrops on a windscreen, which comprises:

means of acquiring images by a camera through the windscreen, camera more particularly focused at infinite,

means of retrieving contours of the spots present on the acquired images,

means of realizing the histogram of the widths of contours of the spots,

means of thresholding, beyond a given minimum threshold, of the widths of contours of the spots, in order to identify the possible presence of spots likely to correspond to droplets on the windscreen,

possibly means of reconstructing/characterizing the spots based on the thresholded widths of contour, including at least one means of measuring one of the following parameters;

measure of variation of the greyscale in the spots, measure of blur of said spots, measure of shape of said spots, count of said spots.

means of automatic triggering or automatic modification of a functionality of the vehicle, more particularly actuation of the windscreen wipers.

14. A vehicle rain sensing system for sensing rain on a windshield comprising of:

a camera for capturing an image of raindrops and generating information in response thereto;

a processor for processing said information and generating contour information of said raindrops; and

a control for energizing at least one windshield wiper in response to said contour information.

15. The vehicle rain sensing system as claimed in claim 14 wherein said camera is set at infinite focus.

16. The vehicle rain sensing system as claimed in claim 14 in response wherein said processor thereto generates a histogram in response to said raindrops.

17. The vehicle rain sensing system as claimed in claim 16 wherein said histogram is a histogram of widths of raindrops.

18. The vehicle rain sensing system as claimed in claim 14 wherein said camera is adapted to capture images situated away from said windshield.

19. The vehicle rain sensing system as claimed in claim 18 wherein said camera is located in a passenger compartment of said vehicle.