Method and apparatus for discriminating the colour of road markings

• US 20050129279A1
• Filed: 11/05/2004
• Published: 06/16/2005
• Est. Priority Date: 11/07/2003
• Status: Active Grant

• Current Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Unwin, Jonathan James
• Granted Patent: US 7,613,326 B2
• Time in Patent Office: Days
• US Class Current: 382/104
• CPC Class Codes: B60T 2201/08 Lane monitoring; Lane Keeping Systems
• CPC Class Codes: B60T 2201/089 using optical detection
• CPC Class Codes: G01J 2003/466 Coded colour; Recognition of predetermined colour; Determining proximity to predetermined colour
• CPC Class Codes: G01J 3/50 using electric radiation detectors
• CPC Class Codes: G01J 3/51 using colour filters
• CPC Class Codes: G06V 20/588 Recognition of the road, e.g. of lane markings; Recognition of the vehicle driving pattern in relation to the road
• CPC Class Codes: G08G 1/161 Decentralised systems, e.g. inter-vehicle communication

Abstract

A method of discriminating between road markings of at least two colours, comprises: capturing an image of a road and at least one road marking with a monochrome camera having a first colour response in a first area of a field of view of the camera and a second colour response in the second area of the field of view; and determining the change in intensity of the captured image of the road marking between the first and second areas. Apparatus for discriminating between road markings is also disclosed.

Claims

1. A method of discriminating between road markings of at least two colours, comprising the steps of:

providing a monochrome camera having a first colour response in a first area of a field of view of said camera and a second colour response in a second area of said field of view;

(b) capturing an image of at least one road marking with the monochrome camera provided in step (a); and

(c) determining a change in intensity of said captured image of said road marking between said first and second areas in said field of view.

2. The method of claim 1 wherein step (c) includes the substeps of:

(c1) comparing the intensity of said captured image in said first and second areas and;

(c2) discriminating between said at least two colours according to the contrast in intensity between said first and second areas.

3. The method of claim 1 wherein said camera is adapted to be fitted to a vehicle and further wherein the method determines the colour of a road marking from said vehicle.

4. The method of claim 1 wherein step (b) includes viewing the image through a filter having at least two sections, said filter sections having different absorbance spectra that provide said different colour response of said first and second areas.

5. The method of claim 4 wherein at least one of said sections of said filter is coloured, and further wherein the method determines from said change in intensity whether said road marking is one of a similar colour to said coloured section or is of and a different colour from said coloured section.

6. The method of claim 1 wherein the markings are lane boundaries marked on a road.

7. The method of claim 1, further including subsequent to step (c), determining a road marking colour from measured changes in intensity of the image of said road marking between said first and second areas of said field of view and then providing said road marking colour determination to an automotive guidance system.

8. The method of claim 1, further including a step of discriminating between further colours of road marking by providing said camera with at least one further area in said field of view, said at least one further area having a colour response different from said colour responses of said first and second areas.

9. The method of claim 8 wherein the method discriminates said colour of said different colour road markings from measured changes in intensity of the image of the road marking between the first, second and further areas.

10. The method of claim 1, which further detects an edge of a road.

11. An apparatus afforded adapted to be fitted to a vehicle and capable of discriminating between at least a first colour and a second colour of road markings, the apparatus comprising:

a monochrome camera arranged to view a road ahead of said vehicle, said camera having a first colour response in a first area of a field of view of said camera and a second colour response in a second area of said field of view; and

a processing unit, arranged to capture images from said camera and determine from said capture images a position of said road markings said processing unit being arranged to discriminate between said first and second colours of said road markings from a change in intensity of said captured image of said road markings between said first and second areas in said field of view.

12. The apparatus of claim 11 wherein said camera is provided with a filter having at least two sections, said filter having different absorbance spectra that provide said different colour response of said first and second areas.

13. The apparatus of claim 12 wherein at least one of said filter sections is coloured, said coloured filter section being one of close to and the same as one of said colours of road markings to be discriminated.

14. The apparatus of claim 13 wherein said filter is of the form of a background having a band of colour forming said coloured area.

15. The apparatus of claim 14 wherein said band of colour is straight and generally parallel to a road surface.

16. The apparatus of claim 12 wherein said camera has a lens, and said filter is provided between said lens and said image to be captured.

17. The apparatus of claim 12 wherein said filter covers a majority of said field of view.

18. The apparatus of claim 11 wherein said monochrome camera is provided with at least one further area in said field of view, said at least one further area having a colour response different from said colour responses of said first and second areas.

19. The apparatus of claim 11 wherein said monochrome camera is arranged to detect an edge of a road.

20. The apparatus of claim 11 wherein said monochrome camera is included in an automotive guidance system.

21. An apparatus capable of discriminating between at least a first colour and a second colour of road markings, the apparatus comprising:

a vehicle;

a monochrome camera mounted upon said vehicle, said monochrome camera arranged to view a road ahead of said vehicle, said camera having a first colour response in a first area of a field of view of said camera and a second colour response in a second area of said field of view; and

a processing unit, arranged to capture images from said camera and to determine from said captured images a position of said road markings, said processing unit being arranged to discriminate between said first and second colours of said road markings from a change in intensity of said captured image of said road markings between said first and second areas in said field of view.