Apparatus for measuring vehicle queue length, method for measuring vehicle queue length, and computer-readable recording medium storing computer program for measuring vehicle queue length

• US 9,361,801 B2
• Filed: 07/30/2012
• Issued: 06/07/2016
• Est. Priority Date: 08/10/2011
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Ochi, Mitsuru
• Primary Examiner(s): Trammell, James
• Assistant Examiner(s): Malhotra, Sanjeev
• Application Number:
  US13/561,740
• Publication Number:
  US 20130041573A1
• Time in Patent Office: 1,408 Days
• Field of Search: 701/1, 701/23, 701/118, 705/14.66, 340/901, 340/907, 340/917, 340/932
• US Class Current: 1/1
• CPC Class Codes: G01S 13/345 using triangular modulation
• CPC Class Codes: G01S 13/584 adapted for simultaneous range and velocity measurements
• CPC Class Codes: G01S 13/66 Radar-tracking systems; Analogous systems
• CPC Class Codes: G01S 13/91 for traffic control G01S13/93 takes precedence
• CPC Class Codes: G08G 1/0116 from roadside infrastructure, e.g. beacons
• CPC Class Codes: G08G 1/0133 for classifying traffic situation
• CPC Class Codes: G08G 1/0145 for active traffic flow control
• CPC Class Codes: G08G 1/052 with provision for determining speed or overspeed speed measuring in general G01P
• CPC Class Codes: G08G 1/08 according to detected number or speed of vehicles

Abstract

An apparatus includes: a processor that executed a procedure, the procedure including: detecting a moving vehicle as the moving vehicle approaches a vehicle queue based on a signal from a sensor, acquiring a position and a speed of the moving vehicle based on the signal, calculating a stop position of the moving vehicle based on a change in the position and the speed of the moving vehicle, and calculating a length of the vehicle queue based on the stop position of the moving vehicle.

Claims

1. An apparatus for measuring a vehicle queue length comprising:

a memory; and

a processor coupled to the memory and configured to;

detect a moving vehicle as the moving vehicle approaches a vehicle queue based on a signal from a sensor;

acquire a position and a speed of the moving vehicle based on the signal;

calculate a stop position of the moving vehicle based on a change in the position and the speed of the moving vehicle; and

calculate a length of the vehicle queue based on the stop position of the moving vehicle,

wherein the processor is further configured to calculate another length of another vehicle queue by a sum of a certain distance and the length of the vehicle queue, when another vehicle that follows the moving vehicle is not detected before a given period elapses from the time when the moving vehicle stops or is not detected.

2. The apparatus according to claim 1, wherein the sensor faces a front surface of the moving vehicle and emits the signal.

3. The apparatus according to claim 1, wherein the vehicle queue comprises a plurality of vehicles, and a first vehicle of the plurality of vehicles is obstructed by a second vehicle of the plurality of vehicles.

4. The apparatus according to claim 1, wherein the sensor is installed at an intersection.

5. The apparatus according to claim 1,

wherein the processor is further configured to:

calculate an acceleration of the moving vehicle based on the change in the speed of the moving vehicle;

determine that the moving vehicle is decelerating based on the acceleration, and

wherein the length of the vehicle queue is calculated when it is determined that the moving vehicle is decelerating.

6. The apparatus according to claim 5,

wherein the processor is further configured to:

acquire, from a traffic signal, timing information that indicates a switching timing of the traffic signal;

specify a movement control period during which the traffic signal prohibit movement of vehicles in the vehicle queue, based on the timing information, and

wherein the stop position of the moving vehicle is calculated only within the movement control period.

7. The apparatus according to claim 6,

wherein the processor is further configured to:

determine a deceleration determination threshold according to the acceleration of the moving vehicle within a movement permission period during which the traffic signal permits movement of the vehicles in the vehicle queue, and

wherein it is determined that the moving vehicle is decelerating when the acceleration is lower than the deceleration determination threshold.

8. A method for measuring a vehicle queue length comprising:

detecting a moving vehicle as the moving vehicle approaches a vehicle queue based on a signal from a sensor;

acquiring a position and a speed of the moving vehicle based on the signal;

calculating a stop position of the moving vehicle based on a change in the position and the speed of the moving vehicle;

calculating the length of the vehicle queue based on the stop position of the moving vehicle; and

calculating another length of another vehicle queue by a sum of a certain distance and the length of the vehicle queue, when another vehicle that follows the moving vehicle is not detected before a given period elapses from the time when the moving vehicle stops or is not detected.

9. The method according to claim 8, wherein the vehicle queue comprises a plurality of vehicles, and a first vehicle of the plurality of vehicles is obstructed by a second vehicle of the plurality of vehicles.

10. The method according to claim 8 further comprising:

calculating an acceleration of the moving vehicle based on the change in the speed of the moving vehicle;

determining that the moving vehicle is decelerating based on the acceleration; and

wherein the length of the vehicle queue is calculated when it is determined that the moving vehicle is decelerating.

11. The method according to claim 10 further comprising:

acquiring, from a traffic signal, timing information that indicates a switching timing of the traffic signal;

specifying a movement control period during which the traffic signal prohibit movement of vehicles in the vehicle queue, based on the timing information; and

wherein the stop position of the moving vehicle is calculated only within the movement control period.

12. The method according to claim 11 further comprising:

determining a deceleration determination threshold according to the acceleration of the moving vehicle within a movement permission period during which the traffic signal permits movement of the vehicles in the vehicle queue; and

wherein it is determined that the moving vehicle is decelerating when the acceleration is lower than the deceleration determination threshold.

13. A non-transitory computer-readable recording medium storing a program for causing a computer to execute a process for measuring a vehicle queue length, the process comprising:

detecting a moving vehicle as the moving vehicle approaches a vehicle queue based on a signal from a sensor;

acquiring a position and a speed of the moving vehicle based on the signal;

calculating a stop position of the moving vehicle based on a change in the position and the speed of the moving vehicle;

calculating the length of the vehicle queue based on the stop position of the moving vehicle; and

calculating another length of another vehicle queue by a sum of a certain distance and the length of the vehicle queue, when another vehicle that follows the moving vehicle is not detected before a given period elapses from the time when the moving vehicle stops or is not detected.

14. The non-transitory computer-readable recording medium according to claim 13, wherein the vehicle queue comprises a plurality of vehicles, and a first vehicle of the plurality of vehicles is obstructed by a second vehicle of the plurality of vehicles.

15. The non-transitory computer-readable recording medium according to claim 13, the process further comprising:

calculating an acceleration of the moving vehicle based on the change in the speed of the moving vehicle;

determining that the moving vehicle is decelerating based on the acceleration; and

wherein the length of the vehicle queue is calculated when it is determined that the moving vehicle is decelerating.

16. The non-transitory computer-readable recording medium according to claim 15, the process further comprising:

acquiring, from a traffic signal, timing information that indicates a switching timing of the traffic signal;

specifying a movement control period during which the traffic signal prohibit movement of vehicles in the vehicle queue, based on the timing information; and

wherein the stop position of the moving vehicle is calculated only within the movement control period.

17. The non-transitory computer-readable recording medium according to claim 16, the process further comprising:

determining a deceleration determination threshold according to the acceleration of the moving vehicle within a movement permission period during which the traffic signal permits movement of the vehicles in the vehicle queue; and

wherein it is determined that the moving vehicle is decelerating when the acceleration is lower than the deceleration determination threshold.