Method for exposure control for a camera in a motor vehicle

• US 8,872,918 B2
• Filed: 04/27/2009
• Issued: 10/28/2014
• Est. Priority Date: 05/03/2008
• Status: Active Grant

• Current Assignee: ADC GmbH (TE Connectivity Ltd. (United Kingdom))
• Original Assignee: ADC GmbH (TE Connectivity Ltd. (United Kingdom))
• Inventors: Krkel, Dieter
• Primary Examiner(s): Rao, Andy
• Assistant Examiner(s): WALKER, JARED T
• Application Number:
  US12/990,567
• Publication Number:
  US 20110157362A1
• Time in Patent Office: 2,010 Days
• Field of Search: 348/148
• US Class Current: 348/148
• CPC Class Codes: B60R 2300/105 using multiple cameras
• CPC Class Codes: H04N 23/73 by influencing the exposure time

Abstract

A method for exposure control for a camera system in a motor vehicle is provided. The camera system records a sequence of images of the surroundings of the vehicle using an optimal exposure time. The optimal exposure time is predetermined depending on the brightness of the surroundings or on the brightness of individual objects in the image. If the optimal exposure time is longer than a predetermined threshold value, at least one intermediate image is recorded using a short predetermined exposure time, i.e. an exposure time shorter than the optimal exposure time. At least two driver assistance functions are executed on the basis of the image data of the camera system. The image data recorded using the optimal exposure time is used for a first driver assistance system and the image data recorded using the short exposure time is used for a second driver assistance system.

Claims

1. A method for exposure control for a camera system in a motor vehicle, the method comprising:

recording, by the camera system, a sequence of images of the surroundings of the vehicle using an optimal exposure time which is predetermined in dependence on the brightness of the surroundings or on the brightness of individual objects in the image, each of the images being recorded during a respective refresh time;

if the optimal exposure time is longer than a predetermined threshold value for avoiding motion blur in the images;

reducing each respective refresh time to include a first refresh time and a second refresh time;

recording a first image during the first refresh time and a second image during the second refresh time, the first image is recorded using a first exposure time, and the second image is recorded using a second exposure time which is shorter than the first exposure time; and

executing at least two driver assistance functions on the basis of the first image and the second image of the camera system,

wherein the first image is used for a first driver assistance system and the second image is used for a second driver assistance system.

2. The method of claim 1, wherein the predetermined threshold value depends on the speed of the motor vehicle.

3. The method of claim 1, wherein images are recorded using short and long exposure times in an alternating manner.

4. The method of claim 1, wherein the first driver assistance system is a lane detection system or a high beam assistance system.

5. The method of claim 1, wherein the second driver assistance system is a traffic sign recognition system.

6. The method of claim 5, wherein the image data recorded using the short exposure time is used for traffic sign recognition at night.

7. The method of claim 1, wherein images are recorded for lane detection or high beam assistance and traffic sign recognition in an alternating manner.

8. The method of claim 1, wherein a refresh rate is constant for all driver assistance systems.

9. The method of claim 1, wherein the interrelationship between the exposure time for the image exposed using a short exposure time and the speed of the motor vehicle is inversely proportional.

10. A camera system capable of storing and executing the method of claim 1.

11. A motor vehicle with a camera system of claim 10.