Vehicle detection apparatus and vehicle detection method

• US 20020011939A1
• Filed: 06/22/2001
• Published: 01/31/2002
• Est. Priority Date: 06/22/2000
• Status: Active Grant

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Mizushima, Koichiro
• Granted Patent: US 6,504,490 B2
• Time in Patent Office: Days
• US Class Current: 340/943
• CPC Class Codes: G08G 1/04 using optical or ultrasonic detectors
• CPC Class Codes: G08G 1/056 with provision for distinguishing direction of travel

Abstract

There are provided a vehicle detection apparatus and a vehicle detection method which are capable of detecting a sound source even when a plurality of vehicles are traveling simultaneously or when there are noises produced from something other than the desired vehicle and calculating the location in the vehicle traveling direction and the lane direction of the sound source and the number of passing vehicles. In the vehicle detection apparatus and the vehicle detection method, noises are collected by a microphone array (402) comprising a plurality of microphones arranged in the form of a matrix in the same plane, the outputs thereof are sampled periodically with time windows in a noise component matrix calculation section (122), the direction in the vehicle traveling direction and the lane direction of the sound source in each window is estimated in an α-direction calculation section (410) and a β-direction calculation section (417), the vehicle is detected by the degree of similarity between the estimated directions in the vehicle traveling direction and traveling sound templates in a vehicle detection section (124), and the estimated directions in the lane direction are counted for each lane and the location in the lane direction of the sound source is detected in a lane detection section (312).

Claims

1. A vehicle detection apparatus comprising a sound collection means placed in the vicinity of a road and comprising a plurality of microphones;

a direction estimation means for sampling the input signals from the sound collection means periodically with time windows and estimating the direction of a sound source in each time window; and

a similarity calculation means for calculating the degree of similarity between the estimation results by the direction estimation means and a plurality of templates which indicate a change in the direction of the sound source with time while the vehicle is traveling.

2. The vehicle detection apparatus as set forth in claim 1, wherein the sound collection means comprises a plurality of microphones aligned on a line parallel to the vehicle traveling direction.

3. The vehicle detection apparatus as set forth in claim 1, wherein the sound collection means comprises a plurality of microphones aligned on a line parallel to the vehicle traveling direction and a plurality of microphones aligned on a line perpendicular to the vehicle traveling direction.

4. The vehicle detection apparatus as set forth in claim 3, wherein the direction estimation means comprises an estimation means for estimating the direction in the vehicle traveling direction and the lane direction of the sound source.

5. The vehicle detection apparatus as set forth in claim 4, which comprises counters for counting the estimation results by the direction estimation means for each lane and a lane detection means for detecting the location in the lanes of the sound source based on the counting values of these counters, when the road has a plurality of lanes.

6. The vehicle detection apparatus as set forth in claim 1, wherein the sound collection means comprises a plurality of microphones arranged in the form of a matrix in the same plane.

7. The vehicle detection apparatus as set forth in claim 6, wherein the direction estimation means comprises an estimation means for estimating the direction in the vehicle traveling direction and the lane direction of the sound source two-dimensionally.

8. The vehicle detection apparatus as set forth in claim 7, wherein the direction estimation means comprises an estimation means for estimating the direction of the sound source by scanning in the vehicle traveling direction with the direction of the sound source in the lane direction limited to the center of the road.

9. The vehicle detection apparatus as set forth in claim 7, wherein the direction estimation means comprises an estimation means for estimating the direction of the sound source by scanning in the lane direction with the direction of the sound source in the vehicle traveling direction limited.

10. The vehicle detection apparatus as set forth in claim 7, which further comprises a first counter which counts the estimation results by the direction estimation means for each lane, a lane location detection means for detecting the location in the lanes of the sound source based on the counting values of the counter, and a second counter which counts the detection results by the lane location detection means for each lane, when the road has a plurality of lanes.

11. The vehicle detection apparatus as set forth in any one of claims 1 to 10, wherein the similarity calculation means comprises a comparison means for comparing the plurality of templates with the estimation results.

12. The vehicle detection apparatus as set forth in claim 11, wherein the plurality of templates are prepared by using the sound of a vehicle when the vehicle is caused to travel at different velocities.

13. The vehicle detection apparatus as set forth in claim 11, wherein the plurality of templates are prepared by expanding or contracting the time base of a template prepared by using the sound of a vehicle traveling at a constant speed, and the similarity calculation means comprises a time base expansion means for expanding or contracting the time base of the template.

14. The vehicle detection apparatus as set forth in any one of claims 1 to 13, wherein the sound collection means comprises a plurality of microphones the number of which is equal to or greater than “

number of assumed sound sources+1”

.

15. A vehicle detection method comprising a sound collection step in which the noises produced by a traveling vehicle are collected by a plurality of microphones placed in the vicinity of a road;

a direction estimation step in which the input signals from the plurality of microphones are sampled periodically with time windows and the direction of a sound source is estimated in each time window; and

a similarity calculation step in which the degree of similarity between the estimation results by the direction estimation step and templates which indicate a change in the direction of the sound source with time while the vehicle is traveling is calculated.

23. The vehicle detection method as set forth in any one of claims 15 to 22, wherein in the vehicle detection step, the degree of similarity between the templates prepared by using the sounds of a vehicle traveling at different velocities and the estimation results is calculated.

24. The vehicle detection method as set forth in any one of claims 15 to 22, wherein the vehicle detection step further comprises a velocity detection step in which the degree of similarity between the templates prepared by expanding or contracting the time base of a template prepared by using the sounds of a vehicle traveling at a constant speed and the estimation results is calculated and, according to the result of the calculation, the velocity of the detected vehicle is calculated from the expansion ratio of the template and the vehicle velocity used for preparing the template.

25. The vehicle detection method as set forth in any one of claims 15 to 24, wherein template matching is used for calculating the degree of similarity between the templates and the estimation results.

26. The vehicle detection method as set forth in any one of claims 15 to 24, wherein DP matching is used for calculating the degree of similarity between the templates and the estimation results.

27. The vehicle detection method as set forth in any one of claims 15 to 26, wherein the number of the plurality of microphones is equal to or greater than “

number of assumed sound sources+1”

.

16. A vehicle detection method comprising a sound collection step in which the noises produced by a traveling vehicle are collected by a plurality of microphones aligned on a line parallel to the vehicle traveling direction and placed in the vicinity of a road;

a direction estimation step in which the input signals from the plurality of microphones are sampled periodically with time windows and the direction of a sound source is estimated in each time window; and

a vehicle detection step in which the degree of similarity between the estimation results by the direction estimation step and a plurality of templates which indicate a change in the direction of the sound source with time while the vehicle is traveling is calculated and the vehicle is detected based on the result of the calculation.

17. A vehicle detection method comprising a sound collection step in which the noises produced by a traveling vehicle are collected by a plurality of microphones aligned on a line parallel to the vehicle traveling direction and on a line perpendicular to the vehicle traveling direction and placed in the vicinity of a multi-lane road;

a direction estimation step in which the input signals from the plurality of microphones are sampled periodically with time windows and the direction in the vehicle traveling direction and the lane direction of a sound source is estimated in each time window;

a vehicle detection step in which the degree of similarity between the estimation results in the vehicle traveling direction by the direction estimation step and a plurality of templates which indicate a change in the direction of the sound source with time while the vehicle is traveling is calculated and the vehicle is detected based on the result of the calculation; and

a lane detection step in which the estimation results in the lane direction by the direction estimation step are counted for each lane and the location in the lanes of the sound source is detected based on the counting values.

18. A vehicle detection method comprising a sound collection step in which the noises produced by a traveling vehicle are collected by a plurality of microphones arranged in the form of a matrix in the same plane and placed in the vicinity of a multi-lane road;

a direction estimation step in which the input signals from the plurality of microphones are sampled periodically with time windows and the direction in the vehicle traveling direction and the lane direction of a sound source is estimated in each time window;

a vehicle detection step in which the degree of similarity between the estimation results in the vehicle traveling direction by the direction estimation step and a plurality of templates which indicate a change in the direction of the sound source with time while the vehicle is traveling is calculated and the vehicle is detected based on the result of the calculation; and

a lane detection step in which the estimation results in the lane direction by the direction estimation step are counted for each lane and the location in the lanes of the sound source is detected based on the counting values.

19. The vehicle detection method as set forth in claim 18, wherein in the direction estimation step, the direction of the sound source is estimated by scanning in the vehicle traveling direction with the direction of the sound source in the lane direction limited to the center of the road.

20. The vehicle detection method as set forth in claim 18, wherein in the direction estimation step, the direction of the sound source is estimated by scanning in the lane direction with the direction of the sound source in the vehicle traveling direction limited.

22. The vehicle detection method as set forth in claim 20, wherein in the direction estimation step, the direction of the sound source is estimated by scanning in the lane direction with the direction of the sound source in the vehicle traveling direction limited.

21. A vehicle detection method comprising a sound collection step in which the noises produced by a traveling vehicle are collected by a plurality of microphones arranged in the form of a matrix in the same plane and placed in the vicinity of a multi-lane road;

a direction estimation step in which the input signals from the plurality of microphones are sampled periodically with time windows and the direction in the vehicle traveling direction and the lane direction of a sound source is estimated in each time window; and

a lane-specific vehicle detection step in which the estimation results in the lane direction by the direction estimation step are counted for each lane to carry out vehicle detection and the detected vehicles are counted for each lane.