Method and system for detecting with laser the passage by a vehicle of a point for monitoring on a road

• US 7,405,676 B2
• Filed: 02/18/2005
• Issued: 07/29/2008
• Est. Priority Date: 09/10/2004
• Status: Active Grant

• Current Assignee: Gatsometer B.V. (Sensys Gatso Group AB)
• Original Assignee: Gatsometer B.V. (Sensys Gatso Group AB)
• Inventors: Janssen, Theodorus Maria
• Primary Examiner(s): Goins; Davetta W.
• Assistant Examiner(s): Fan; Hongmin
• Application Number:
  US11/061,367
• Publication Number:
  US 20060055560A1
• Time in Patent Office: 1,257 Days
• Field of Search: 340/942, 340555-557, 340555- 7, 250/200, 250/222.1, 250/224
• US Class Current: 340/942
• CPC Class Codes: G01S 17/88 Lidar systems specially adapted for specific applications
• CPC Class Codes: G08G 1/01 Detecting movement of traffic to be counted or controlled G08G1/07 - G08G1/14 take precedence

Abstract

The invention relates to a method for detecting the passage by a vehicle of a determined point for monitoring on a road, wherein from a remotely situated location a laser beam is transmitted continuously to the point for monitoring, reflections from the transmitted laser beam are received at the remotely situated location, and it is determined from the received reflections that the vehicle is passing the point for monitoring. The laser beam can be transmitted at right angles to the travel direction of the passing vehicle. The detection can be used to activate a red-light camera, to measure the speed of the vehicle or measure the traffic intensity, without sensors, for instance induction loops, having to be arranged in the road for this purpose. The invention further relates to a system for performing this method.

Claims

1. A method for detecting the passage of a vehicle past a determined point for monitoring a road, comprising transmitting at least two substantially parallel laser beams from a remotely situated location to the point for monitoring;

receiving reflections from the at least two transmitted laser beams at the remotely situated location, and determining from the received reflections that the vehicle is passing the point for monitoring, wherein said laser beams are transmitted substantially continuously, further wherein said determining is by comparing the received reflections of the at least two laser beams, wherein a time profile of the vehicle is determined from a number of successively received reflections, and the validity of the detection of that vehicle passing the point for monitoring is determined if the time profiles from reflections of the various laser beams correspond precisely.

2. The method of claim 1, wherein the at least one laser beam is transmitted substantially at right angles to the travel direction of the passing vehicle.

3. The method of claim 1, wherein an activating signal is generated when a vehicle passes the point for monitoring in a predetermined direction.

4. The method of claim 3, wherein an identification of the transmitting and receiving location is linked to the activating signal.

5. The method of claim 3, wherein at least one picture record of the passing vehicle is made on the basis of the activating signal.

6. The method of claim 3, wherein the speed and the travel direction of the passing vehicle is calculated from the received reflections of die laser beam.

7. The method of claim 6, wherein the calculated speed is linked to the activating signal.

8. The method of claim 1, wherein the transmitting and receiving location and the point for monitoring are such that each laser beam hits passing vehicles at a characteristic height.

9. The method of claim 1, wherein the road comprises a number of lanes, on each of which a specific point is to be monitored, and for each lane a laser beam is transmitted at a related angle from the transmitting and receiving location.

10. A detection system for detecting the passage of a vehicle past a determined point for monitoring a road, comprising a transmitting and receiving device disposed at a remote location for:

(1) transmitting at least one laser beam substantially continuously to the point for monitoring, (2) receiving reflections from the at least one transmitted laser beam, and (3) determining from the received reflections that a vehicle is passing the point for monitoring,

wherein the transmitting and receiving device is adapted to transmit at least two substantially parallel laser beams and to determine the moment of passing of the point for monitoring by said vehicle by comparing the received reflections from the various laser beams,

further wherein the transmitting and receiving device is adapted to determine a time profile of the vehicle from a number of successively received reflections of a laser beam, and to accept a detection that the vehicle is passing the point for monitoring as valid only if the profiles determined from reflections of the various laser beams correspond precisely.

11. The detection system of claim 10, wherein the transmitting and receiving device is adapted to transmit at least one laser beam substantially at right angles to the travel direction of die passing vehicle.

12. The detection system of claim 10, wherein the transmitting and receiving device is adapted to generate an activating signal when a vehicle passes the point for monitoring in a predetermined direction.

13. The detection system of claim 12, wherein the transmitting and receiving device is adapted to link its identification to the activating signal.

14. The detection system of claim 12, further comprising a device connected controllably to the transmitting and receiving device for making at least one picture record of the passing vehicle.

15. The detection system of claim 10, wherein the transmitting and receiving device is adapted to calculate from the received reflections of various laser beams the speed and the travel direction of the passing vehicle.

16. The detection system of claim 12, wherein the transmitting and receiving device is adapted to link the calculated speed to the activating signal.

17. The detection system of claim 10, wherein the transmitting and receiving device is disposed at a distance from the point for monitoring and adapted to transmit a laser beam such that each laser beam bits passing vehicles at a characteristic height.

18. The detection system of claim 10, wherein the road comprises a uiurnber of lanes, on each of which a specific point is to be monitored, and the transmitting and receiving device is adapted to transmit for each lane a laser beam at a related angle.