System for optical acquisition of the road

• US 6,067,111 A
• Filed: 04/18/1997
• Issued: 05/23/2000
• Est. Priority Date: 04/18/1996
• Status: Expired due to Term

• Current Assignee: ADC GmbH (TE Connectivity Ltd. (United Kingdom))
• Original Assignee: Daimler AG (Mercedes-Benz Group AG)
• Inventors: Hahn, Stefan, Stein, Fridtjof
• Primary Examiner(s): Britton, Howard
• Assistant Examiner(s): VO, TUNG T
• Application Number:
  US08/847,970
• Time in Patent Office: 1,131 Days
• Field of Search: 348/113, 348/117, 348/135, 348/148, 348/149, 348/159, 348/162, 340/435, 340/436, 340/104, 340/901, 340/904, 340/905, 340/937, 340/932.2, 358/108, 382/1, 365/4
• US Class Current: 348/148
• CPC Class Codes: B60R 16/0237 circuits concerning the atmospheric environment meteorology G01W
• CPC Class Codes: G05D 1/0246 using a video camera in combination with image processing means

Abstract

In a system for optical acquisition of the road and traffic in front of a road vehicle by electronic processing and evaluation of the image signals from a video camera mounted at the level of the top edge of the windshield of the vehicle, with the optical axis of the camera running at an angle to the road in a plane that is parallel to or approximately parallel to the vertical lengthwise central plane of the vehicle, the lens of the video camera is designed as a wide-angle lens and the slope angle that the optical axis of the lens forms with the plane of the road is less than half the total aperture angle of the lens, but corresponds approximately to half of its value.

Claims

1. Device for detecting a road and objects therein in an area of interest near a vehicle, by means of electronic signals from a video camera mounted on an elevated part of said vehicle, wherein:

said camera is oriented so that an optical axis of a camera lens thereof forms a slope angle relative to a plane of said road, which slope angle is less than but approximately equal to one half of an aperture angle of said camera lens;

said camera lens is a wide angle lens with an aperture angle greater than approximately sixty degrees; and

said camera has a photosensitive detector element which is situated in an eccentric portion of an image area of said camera lens, which portion of said image area lies approximately between said optical axis of said camera lens and a part of said image area which corresponds to a farthest edge of said area of interest.

2. Device according to claim 1 wherein said wide angle lens has an aperture angle greater than approximately ninety degrees.

3. System according to claim 2 wherein said predetermined minimum distance is approximately equal to the value h/tanε

, where h is vertical distance of the center of lens from road and ε

is the slope angle that the optical axis of the camera lens forms with the plane of the road.

4. System according to claim 1 wherein said predetermined minimum distance is approximately equal to the value h/tanε

, where h is vertical distance of the center of lens from road and ε

is the slope angle that the optical axis of the camera lens forms with the plane of the road.

5. The device according to claim 1, wherein said optical axis of said camera lens is pointed in a direction which corresponds approximately to an edge of said area of interest nearest said vehicle.

6. A camera for detecting a road and objects therein in an area of interest near of a vehicle, said camera comprising:

a wide angle lens having an aperture angle greater than ninety degrees; and

a photosensitive detector element which is mounted off center in an image area of said lens, in a portion of said image area such that, when said camera is mounted on said vehicle with an optical axis of said lens forming an angle with a plane of said road which is less than but approximately equal to one half of said aperture angle, said portion lies approximately between said optical axis of said lens and a part of said image area which corresponds to a farthest edge of said area of interest.

7. Method for detecting a road and objects in an area of interest near a vehicle, comprising:

providing a video camera mounted on said vehicle, said camera having a wide angle lens and a photodetector disposed in an image area of said wide angle lens;

fixing a mounting direction of said camera on said vehicle such that an optical axis of said wide angle lens is directed approximately toward an edge of said area of interest which edge is nearest said vehicle, so that said area of interest lies in an eccentric portion of a field of view of said lens, approximately from said optical axis to an edge of said field of view;

processing signals from said photodetector in an eccentric portion of said image area corresponding to said area of interest to identify said road and objects in said area of interest.

8. The method according to claim 7 wherein in said step of providing a video camera, said photodetector is provided in an eccentric portion of said image area which corresponds to said area of interest.

9. Apparatus for detecting a road and objects in an area of interest near a vehicle, comprising:

a video camera mounted on said vehicle for detecting objects in said area of interest;

a wide angle lens on said video camera, providing an optical image area in said camera; and

a photodetector in said video camera, disposed in said image area;

wherein said video camera is mounted on said vehicle with an optical axis of said wide angle lens oriented in a direction which points approximately at an edge of said area of interest which edge is nearest said vehicle, so that said area of interest lies in an eccentric portion of a field of view of said lens, approximately from said optical axis to an edge of said field of view.

10. The apparatus according to claim 9 wherein said photodetector is disposed in an eccentric portion of said image area which corresponds to said area of interest.