Single camera system and method for range and lateral position measurement of a preceding vehicle

• US 7,545,956 B2
• Filed: 08/12/2005
• Issued: 06/09/2009
• Est. Priority Date: 08/12/2005
• Status: Expired due to Fees

• Current Assignee: Visteon Global Technologies Incorporated (Visteon Corporation)
• Original Assignee: Visteon Global Technologies Incorporated (Visteon Corporation)
• Inventors: Miyahara, Shunji
• Primary Examiner(s): Strege; John B
• Application Number:
  US11/202,917
• Publication Number:
  US 20070035385A1
• Time in Patent Office: 1,397 Days
• Field of Search: 382/106, 340/435
• US Class Current: 382/106
• CPC Class Codes: G01S 11/12 using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 15/86 Combinations of sonar systems with lidar systems; Combinations of sonar systems with systems not using wave reflection
• CPC Class Codes: G01S 15/931 of land vehicles
• CPC Class Codes: G06T 7/70 Determining position or orientation of objects or cameras camera calibration G06T7/80
• CPC Class Codes: G06V 20/58 Recognition of moving objects or obstacles, e.g. vehicles or pedestrians; Recognition of traffic objects, e.g. traffic signs, traffic lights or roads
• CPC Class Codes: G08G 1/16 Anti-collision systems road vehicle drive control systems for predicting or avoiding probable or impending collision otherwise than by control of a particular sub-unit B60W30/08
• CPC Class Codes: G08G 1/166 for active traffic, e.g. moving vehicles, pedestrians, bikes

Abstract

A system for determining range and lateral position of a vehicle is provided. The system includes a camera, a sonar and a processor. The camera is configured to view a long range region of interest and generate an electrical image of the region. The sonar is configured to view a short range region of interest an output a sonar signal. The processor is in electrical communication with the camera and the sonar to receive the electrical image and the sonar signal. The processor analyzes the image and the sonar signal in order to determine the range of an object.

Claims

1. A system for determining range of a vehicle, the system comprising:

a camera configured to view a first region of interest including the vehicle and generate an electrical image of the region;

a sonar sensor configured to detect objects within a second region of interest;

processor in electrical communication with the camera to receive the electrical image, wherein the processor is configured to identify a plurality of windows within the electrical image, each window of the plurality of windows corresponding to a predetermined physical size and target range from the camera, the processor being further configured to evaluate characteristics of a candidate object in relation to each window to identify the vehicle;

the processor in electrical communication with the sonar sensor, the processor configured to identify objects detected by the sonar sensor and determine the range of the objects detected by the sonar sensor;

wherein the window position is determined based on an elevation angle of the camera; and

wherein the lower edge of each window is calculated based on the relationship θ

₁=a tan(−

rc/hc) where hc is the height of the camera from the road surface, rc is the range of window from the camera, and the module is [0, π

].

2. The system according to claim 1, wherein the processor is configured to determine a score indicating likelihood the candidate object is the target.

3. The system according to claim 2, wherein the processor is configured to determine the score based on a size ratio between each window and the characteristics of the candidate object.

4. The system according to claim 1, wherein the predetermined physical size is based on vehicle characteristics.

5. The system according to claim 4, wherein the vehicle characteristics include a width of the vehicle.

6. The system according to claim 4, wherein the vehicle characteristics include a height of the vehicle.

7. The system according to claim 1, wherein the characteristics of the electrical image include edge segments within the electrical image.

8. The system according to claim 7, wherein the edge segments are vertical edge segments.

9. The system according to claim 7, wherein the characteristics of the electrical image include a height of the edge segments.

10. The system according to claim 7, wherein the characteristics of the electrical image include a width of the edge segments.

11. The system according to claim 7, wherein the characteristics of the electrical image include objects constructed from the edge segments.

12. The system according to claim 11, wherein the characteristics of the electrical image include a height of the objects.

13. The system according to claim 11, wherein the characteristics of the electrical image include a width of the objects.

14. The system according to claim 1, wherein a position of each window is determined based on the target range.

15. A system for determining range of a vehicle, the system comprising:

a camera configured to view a first region of interest including the vehicle and generate an electrical image of the region;

a sonar sensor configured to detect objects within a second region of interest;

a processor in electrical communication with the camera to receive the electrical image, wherein the processor is configured to identify a plurality of windows within the electrical image, each window of the plurality of windows corresponding to a predetermined physical size and target range from the camera, the processor being further configured to evaluate characteristics of a candidate object in relation to each window to identify the vehicle;

the processor in electrical communication with the sonar sensor, the processor configured to identify objects detected by the sonar sensor and determine the range of the objects detected by the sonar sensor;

wherein the window position is determined based on an elevation angle of the camera; and

wherein the upper edge of each window is calculated based on the relationship θ

_1h=a tan(r1/(hw−

hc)) where hw is a window height, hc is the height of the camera from the road surface, r1 is the range of window from the camera, and the module is [0, π

].

16. A system for determining range of a vehicle, the system comprising:

a camera configured to view a first region of interest including the vehicle and generate an electrical image of the region;

a sonar sensor configured to detect objects within a second region of interest;

a processor in electrical communication with the camera to receive the electrical image, wherein the processor is configured to identify a plurality of windows within the electrical image, each window of the plurality of windows corresponding to a predetermined physical size and target range from the camera, the processor being further configured to evaluate characteristics of a candidate object in relation to each window to identify the vehicle;

the processor in electrical communication with the sonar sensor, the processor configured to identify objects detected by the sonar sensor and determine the range of the objects detected by the sonar sensor;

wherein the position of each window is determined based on an azimuth angle of the camera; and

wherein the right edge of each window is calculated based on the relationship φ

₁=a tan(−

width_w/(2r1))+π

/2 where window w is the distance from the center of the window to the horizontal edges, r1 is the horizontal range of the window from the camera, and the module is [−

π

/2,π

/2].

17. A system for determining range of a vehicle, the system comprising:

a camera configured to view a first region of interest including the vehicle and generate an electrical image of the region;

a sonar sensor configured to detect objects within a second region of interest;

a processor in electrical communication with the camera to receive the electrical image, wherein the processor is configured to identify a plurality of windows within the electrical image, each window of the plurality of windows corresponding to a predetermined physical size and target range from the camera, the processor being further configured to evaluate characteristics of a candidate object in relation to each window to identify the vehicle;

the processor in electrical communication with the sonar sensor, the processor configured to identify objects detected by the sonar sensor and determine the range of the objects detected by the sonar sensor;

wherein the position of each window is determined based on an azimuth angle of the camera; and

wherein the left edge of each window is calculated based on the relationship φ

_1h=a tan(width_w/r1)+π

/2 where window w is the distance from the center of the window to the horizontal edges, r1 is the horizontal range of the window from the camera, and the module is [−

π

/2,π

/2].

18. A method for determining range of a vehicle, the method comprising:

receiving an optical image of a first region of interest onto a camera;

receiving a sonar signal of a second region of interest onto a sonar;

generating an electrical image based on the optical image;

identifying a plurality of windows within the electrical image, each window corresponding to a predetermined physical size and a target range from the camera;

evaluating characteristics of a candidate object within each window signal to identify the vehicle;

evaluating the sonar signal to determine if objects are located within the second region of interest;

wherein the window Position is determined based on an elevation angle of the camera; and

wherein the lower edge of each window is calculated based on the relationship θ

₁=a tan(−

r1/hc) where hc is the height of the camera from the road surface, r1 is the range of window from the camera, and the module is [0, π

].

19. The method according to claim 18, wherein the processor is configured to determine a score indicating likelihood the candidate object is a target vehicle.

20. The method according to claim 19, wherein the processor is configured to determine the score based on a size ratio between each window and the characteristics of the electrical image.

21. The method according to claim 18, wherein the predetermined physical size is based on vehicle characteristics.

22. The method according to claim 21, wherein the vehicle characteristics include a width of the vehicle.

23. The method according to claim 21, wherein the vehicle characteristics include a height of the vehicle.

24. The method according to claim 18, wherein the characteristics of the electrical image include edge segments within the electrical image.

25. The method according to claim 24, wherein the edge segments are vertical edge segments.

26. The method according to claim 24, wherein the characteristics of the electrical image include a height of the edge segments.

27. The method according to claim 24, wherein the characteristics of the electrical image include a width of the edge segments.

28. The method according to claim 24, wherein the characteristics of the electrical image include objects constructed from the edge segments.

29. The method according to claim 28, wherein the characteristics of the electrical image include a height of the objects.

30. The method according to claim 28, wherein the characteristics of the electrical image include a width of the objects.

31. The method according to claim 18, wherein a position of each window is determined based on the target range.

32. The method according to claim 18, wherein evaluating characteristics of the electrical image includes performing an edge enhancement algorithm to the electrical image.

33. The method according to claim 32, wherein the edge enhancement algorithm is a vertical edge enhancement algorithm.

34. The method according to claim 32, wherein evaluating characteristics of the electrical image includes extracting only the electrical image within the window.

35. The method according to claim 32, wherein evaluating characteristics of the electrical image includes binarizing the electrical image utilizing a threshold.

36. The method according to claim 32, wherein evaluating characteristics of the electrical image includes identifying segments from the binarized image.

37. The method according to claim 36, wherein evaluating characteristics of the electrical image includes constructing objects from the segments.

38. The method according to claim 37, wherein evaluating the electrical image, includes determining a score for each object based on the object width, object height position, object height, and segment width.

39. The method according to claim 38, wherein evaluating characteristics of the electrical image, further includes determining a range of the object that is based on the score of the object.

40. The method according to claim 18, further comprising the step of determining the range of objects located within the second region of interest using the sonar signal.

41. The method of claim 18, further comprising the step of:

determining if the object detected within the second region of interest is detected in the first region of interest;

using the sonar signal to determine the range of the object detected within the second region of interest if the object is not detected within the first region of interest.

42. A method for determining range of a vehicle, the method comprising:

receiving an optical image of a first region of interest onto a camera;

receiving a sonar signal of a second region of interest onto a sonar;

generating an electrical image based on the optical image;

identifying a plurality of windows within the electrical image, each window corresponding to a predetermined physical size and a target range from the camera;

evaluating characteristics of a candidate object within each window signal to identify the vehicle;

evaluating the sonar signal to determine if objects are located within the second region of interest;

wherein the window position is determined based on an elevation angle of the camera; and

wherein the upper edge of each window is calculated based on the relationship θ

_1h=a tan(r1/(hw−

hc)) where hw is a window height, hc is the height of the camera from the road surface, r1 is the range of window from the camera, and the module is [0, π

].

43. A method for determining range of a vehicle, the method comprising:

receiving an optical image of a first region of interest onto a camera;

receiving a sonar signal of a second region of interest onto a sonar;

generating an electrical image based on the optical image;

identifying a plurality of windows within the electrical image, reach window corresponding to a predetermined physical size and a target range from the camera;

evaluating characteristics of a candidate object within each window signal to identify the vehicle;

evaluating the sonar signal to determine if objects are located within the second region of interest;

wherein the position of each window is determined based on an azimuth angle of the camera; and

wherein the right edge of each window is calculated based on the relationship φ

₁=a tan(−

width₁₃ /(2*r1))+π

/2 where window w is the distance from the center of the window to the horizontal edges, r1 is the horizontal range of the window from the camera, and the module is [−

π

/2,π

/2].

44. method for determining range of a vehicle, the method comprising:

receiving an optical image of a first region of interest onto a camera;

receiving a sonar signal of a second region of interest onto a sonar;

generating an electrical image based on the optical image;

identifying a plurality of windows within the electrical image, each window corresponding to a predetermined physical size and a target range from the camera;

evaluating characteristics of a candidate object within each window signal to identify the vehicle;

evaluating the sonar signal to determine if objects are located within the second region of interest;

wherein the position of each window is determined based on an azimuth angle of the camera; and

wherein the left edge of each window is calculated based on the relationship φ

_1h=a tan(width_w/(2*r1))+π

/2 where window w is the distance from the center of the window to the horizontal edges, r1 is the horizontal range of the window from the camera, and the module is [−

π

/2,π

/2].