Identical object determination method and apparatus and displacement correction method and apparatus

• US 20040098224A1
• Filed: 07/01/2003
• Published: 05/20/2004
• Est. Priority Date: 07/03/2002
• Status: Active Grant

• Current Assignee: Fuji Jukogyo KK (Subaru Corp.)
• Original Assignee: Fuji Jukogyo KK (Subaru Corp.)
• Inventors: Takahashi, Yasushi
• Granted Patent: US 6,999,896 B2
• Time in Patent Office: Days
• US Class Current: 702/181
• CPC Class Codes: G01S 11/12 using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 13/865 Combination of radar systems with lidar systems
• CPC Class Codes: G01S 13/867 Combination of radar systems with cameras
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 17/86 Combinations of lidar systems with systems other than lidar, radar or sonar, e.g. with direction finders
• CPC Class Codes: G01S 17/931 of land vehicles
• CPC Class Codes: G01S 2013/93271 in the front of the vehicles
• CPC Class Codes: G01S 7/4026 Antenna boresight
• CPC Class Codes: G01S 7/403 in azimuth, i.e. in the horizontal plane
• CPC Class Codes: G01S 7/497 Means for monitoring or calibrating

Abstract

An identical object determination method of determining whether or not objects are detected by a plurality of sensors identical has a determining a relative position and speed thereof, a determining a position error thereof based on the determined positions and calculating a first probability that the detected objects are identical with respect to the position from the determined position error based on a normal distribution concerning the position error, a determining a speed error thereof based on the determined speed and calculating a second probability that the detected objects are identical with respect to the speed from the determined speed error based on a normal distribution concerning the speed error, a calculating a third probability that the detected objects are identical based on the calculated first probability and the calculated second probability, and a determining that the detected objects are identical if the third probability exceeds a first determination value.

Claims

1. An identical object determination method of determining whether or not objects detected by a plurality of sensors are identical, the identical object determination method comprising:

a first step for determining a relative position and relative speed of each of the detected objects;

a second step for determining a position error of each of the detected objects based on the determined positions and calculating a first probability as a probability that the detected objects are identical with respect to the position from the determined position error based on a normal distribution concerning the position error when the plurality of sensors detect the identical object;

a third step for determining a speed error of each of the detected objects based on the determined speed and calculating a second probability as a probability that the detected objects are identical with respect to the speed from the determined speed error based on a normal distribution concerning the speed error when the plurality of sensors detect the identical object;

a fourth step for calculating a third probability as a probability that the detected objects are identical based on the calculated first probability and the calculated second probability; and

a fifth step for determining that the detected objects are identical if the third probability exceeds a first determination value.

2. The identical object determination method as set forth in claim 1 further comprising the steps of:

if the third probability is smaller than the first determination value, extracting the objects in any desired combination from the detected objects and calculating a fourth probability as a probability that the extracted objects, each as a processed object, are identical; and

if the calculated fourth probability exceeds the first determination value, determining that the extracted objects are identical.

3. The identical object determination method as set forth in claim 1 wherein if at least one of the sensors detects a plurality of objects,

the second step selects one object from among the detected objects for each sensor, thereby forming groups, each as a processed object, as different combinations and calculates the first probability as the probability that the objects making up each of the groups are identical with respect to the position,

the third step calculates the second probability as the probability that the objects making up each of the groups are identical with respect to the speed,

the fourth step calculates the third probability as the probability that the objects making up each of the groups are identical based on the calculated first probability and the calculated second probability, and

the fifth step adopts the object detected by one of the sensors as the reference, determines the group having the maximum value of the third probability from among the groups containing the reference object, and if the third probability calculated for the determined group exceeds the first determination value, determines that the objects making up the determined group are identical.

4. The identical object determination method as set forth in claim 2 wherein if at least one of the sensors detects a plurality of objects,

the second step selects one object from among the detected objects for each sensor, thereby forming groups, each as a processed object, as different combinations and calculates the first probability as the probability that the objects making up each of the groups are identical with respect to the position,

the third step calculates the second probability as the probability that the objects making up each of the groups are identical with respect to the speed,

the fourth step calculates the third probability as the probability that the objects making up each of the groups are identical based on the calculated first probability and the calculated second probability, and

the fifth step adopts the object detected by one of the sensors as the reference, determines the group having the maximum value of the third probability from among the groups containing the reference object, and if the third probability calculated for the determined group exceeds the first determination value, determines that the objects making up the determined group are identical.

5. The identical object determination method as set forth in claim 4 wherein the fifth step comprises the steps of:

if the third probability calculated for a first group containing the reference object and the third probability calculated for a second group containing the reference object, different from the first group exceed each the first determination value, comparing the third probability calculated for the first group and the third probability calculated for the second group each with a second determination value greater than the first determination value; and

if the third probability calculated for the first group and the third probability calculated for the second group exceed each the second determination value, determining that the objects making up the first group and the second group are identical;

if either the third probability calculated for the first group or the third probability calculated for the second group exceeds the second determination value, determining that the objects making up the group corresponding to the third probability exceeding the second determination value are identical.

6. The identical object determination method as set forth in claim 1 further comprising the step for correcting the calculated third probability based on history information indicating that the object detected by one sensor is determined identical with which of objects detected by a different sensor.

7. The identical object determination method as set forth in claim 5 further comprising the step for correcting the calculated third probability based on history information indicating that the object detected by one sensor is determined identical with which of objects detected by a different sensor.

8. The identical object determination method as set forth in claim 7 further comprising the step for correcting the calculated third probability based on history information indicating the number of successive times that the object detected by the one sensor has been determined identical with the object detected by the different sensor.

9. The identical object determination method as set forth in claim 1 further comprising the step for correcting the calculated third probability based on history information indicating the third probability calculated for the object detected by one sensor and the object detected by a different sensor.

10. The identical object determination method as set forth in claim 5 further comprising the step for correcting the calculated third probability based on history information indicating the third probability calculated for the object detected by one sensor and the object detected by a different sensor.

11. The identical object determination method as set forth in claim 1 wherein the plurality of sensors are selected from the group containing a sensor for detecting an object based on a pair of picked-up images using stereoscopic image processing, a millimeter wave radar, and a laser radar.

12. The identical object determination method as set forth in claim 8 wherein the plurality of sensors are selected from the group containing a sensor for detecting an object based on a pair of picked-up images using stereoscopic image processing, a millimeter wave radar, and a laser radar.

13. The identical object determination method as set forth in claim 10 wherein the plurality of sensors are selected from the group containing a sensor for detecting an object based on a pair of picked-up images using stereoscopic image processing, a millimeter wave radar, and a laser radar.

14. An identical object determination apparatus for determining whether or not objects detected by a plurality of sensors are identical using an identical object determination method as set forth in claim 1.

15. An identical object determination apparatus for determining whether or not objects detected by a plurality of sensors are identical using an identical object determination method as set forth in claim 12.

16. An identical object determination apparatus for determining whether or not objects detected by a plurality of sensors are identical using an identical object determination method as set forth in claim 13.

18. The identical object determination method as set forth in claim 11 wherein the second step determines that the detected objects are identical if the determined position error is smaller than the first determination value and the determined speed error is smaller than the second determination value.

20. The identical object determination method as set forth in claim 18 wherein the plurality of sensors are selected from the group containing a sensor for detecting an object based on a pair of picked-up images using stereoscopic image processing, a millimeter wave radar, and a laser radar.

22. An identical object determination apparatus for determining whether or not objects detected by a plurality of sensors are identical using an identical object determination method as set forth in claim 20.

41. The displacement correction method as set forth in claim 23 wherein the third step uses an identical object determination method as set forth in claim 1.

17. An identical object determination method of determining whether or not objects detected by a plurality of sensors are identical, the identical object determination method comprising:

a first step for determining a relative position and relative speed of each of the detected objects; and

a second step for determining a position error of each of the detected objects based on the determined positions, comparing the determined position error with a first determination value, determining a speed error of each of the detected objects based on the determined speed, and comparing the determined speed error with a second determination value, thereby separating the detected objects into the identical object and different objects.

19. The identical object determination method as set forth in claim 17 wherein the plurality of sensors are selected from the group containing a sensor for detecting an object based on a pair of picked-up images using stereoscopic image processing, a millimeter wave radar, and a laser radar.

21. An identical object determination apparatus for determining whether or not objects detected by a plurality of sensors are identical using an identical object determination method as set forth in claim 17.

23. A displacement correction method of correcting relative displacement of identical objects detected by one sensor and a different sensor for detecting objects in cooperation with each other, the displacement correction method comprising:

a first step for setting a plurality of correction parameters for correcting relative displacement of the position of the object detected by the one sensor and the position of the object detected by the different sensor;

a second step for relatively correcting the position of the object detected by the different sensor based on the correction parameter;

a third step for determining whether or not the object detected by the one sensor and the object detected by the different sensor, the position of which is corrected based on the correction parameter are identical for each of the correction parameters; and

a fourth step for comparing the comparison results at the third step, determining the correction parameter determined corresponding to the identical object having the best determination result, and determining a feedback correction parameter for making feedback correction of relative displacement of the identical objects detected by the one sensor and the different sensor based on the determined correction parameter.

24. The displacement correction method as set forth in claim 23 wherein the correction parameter is set based on a relative difference between an attachment position of the one sensor and an attachment position of the different sensor.

25. The displacement correction method as set forth in claim 23 wherein the correction parameter is set based on a relative detection position error between the one sensor and the different sensor.

26. The displacement correction method as set forth in claim 24 wherein the correction parameter is set based on a relative detection position error between the one sensor and the different sensor.

27. The displacement correction method as set forth in claim 23 wherein the correction parameter is set based on a relative detection time difference between the one sensor and the different sensor.

28. The displacement correction method as set forth in claim 26 wherein the correction parameter is set based on a relative detection time difference between the one sensor and the different sensor.

29. The displacement correction method as set forth in claim 23 wherein the first step to the third step are repeated two or more times and if the number of times that the correction parameter has been determined corresponding to the identical object exceeds a predetermined determination value, the feedback correction parameter is determined based on the correction parameter.

30. The displacement correction method as set forth in claim 28 wherein the first step to the third step are repeated two or more times and if the number of times that the correction parameter has been determined corresponding to the identical object exceeds a predetermined determination value, the feedback correction parameter is determined based on the correction parameter.

31. The displacement correction method as set forth in claim 23 wherein the first step to the third step are repeated two or more times and if the number of times that the correction parameter has been determined corresponding to the identical object reaches the maximum, the feedback correction parameter is determined based on the correction parameter.

32. The displacement correction method as set forth in claim 28 wherein the first step to the third step are repeated two or more times and if the number of times that the correction parameter has been determined corresponding to the identical object reaches the maximum, the feedback correction parameter is determined based on the correction parameter.

33. The displacement correction method as set forth in claim 23 wherein when comparing the comparison results at the third step, the fourth step uses only the determination result concerning the object more distant from the predetermined determination value with respect to the position.

34. The displacement correction method as set forth in claim 30 wherein when comparing the comparison results at the third step, the fourth step uses only the determination result concerning the object more distant from the predetermined determination value with respect to the position.

35. The displacement correction method as set forth in claim 32 wherein when comparing the comparison results at the third step, the fourth step uses only the determination result concerning the object more distant from the predetermined determination value with respect to the position.

36. The displacement correction method as set forth in claim 23 wherein the plurality of correction parameters are divided into a plurality of groups and the correction parameters belonging to each group are used in one process.

37. The displacement correction method as set forth in claim 34 wherein the plurality of correction parameters are divided into a plurality of groups and the correction parameters belonging to each group are used in one process.

38. The displacement correction method as set forth in claim 35 wherein the plurality of correction parameters are divided into a plurality of groups and the correction parameters belonging to each group are used in one process.

39. The displacement correction method as set forth in claim 37 wherein each group contains one common correction parameter to the groups.

40. The displacement correction method as set forth in claim 38 wherein each group contains one common correction parameter to the groups.

42. A displacement correction apparatus for correcting relative displacement of identical objects detected by a plurality of sensors for detecting objects in cooperation with each other using a displacement correction method as set forth in claim 23.