Magnetic traffic control system

• US 7,765,056 B2
• Filed: 01/04/2007
• Issued: 07/27/2010
• Est. Priority Date: 01/11/2006
• Status: Expired due to Fees

• Current Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Original Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Inventors: Guilhamat, Bernard, Cattin, Viviane, Flament, Bruno, Blanpain, Roland
• Primary Examiner(s): Tran; Khoi
• Assistant Examiner(s): KING, RODNEY P
• Application Number:
  US11/619,791
• Publication Number:
  US 20070162218A1
• Time in Patent Office: 1,300 Days
• Field of Search: 701/117, 701/118, 701/119, 340/905, 340/933, 340/934
• US Class Current: 701/117
• CPC Class Codes: G08G 1/015 with provision for distinguishing between two or more types of vehicles, e.g. between motor-cars and cycles
• CPC Class Codes: G08G 1/042 using inductive or magnetic detectors

Abstract

A system for measuring a magnetic signature of a vehicle, including: at least a first set of sensors (C^x_i) that are stationary and arranged along at least a first direction; at least a second set of sensors (C^y_j) that are stationary and arranged along at least a second direction that intersects the first direction; a common sensor (C^xy₀) arranged at a location where the first set of sensors and the second set of sensors intersect, said common sensor belonging to the first and the second sets of sensors, wherein the first set of sensors and the second set of sensors are arranged so that the vehicle passes above at least part of the sensors of the first and second set of sensors; and a calculation device for calculating a relation between a time signature S_o(t) of the vehicle passing above the common sensor and a spatial profile S_o(x) resulting from measurements made by the first set of sensors.

Claims

1. A system for measuring a magnetic signature of a vehicle, comprising:

at least a first set of sensors (C^x_i) that are stationary and arranged along at least a first direction;

at least a second set of sensors (C^y_j) that are stationary and arranged along at least one second direction that intersects the first direction;

a common sensor (C^xy₀) arranged at a location where the first set of sensors and the second set of sensors intersect, said common sensor belonging to the first and the second sets of sensors,

wherein the first set of sensors and the second set of sensors are arranged so that the vehicle passes above at least part of the sensors of said first and second set of sensors; and

calculation means for calculating a relation between a time signature S_o(t) of the vehicle passing above the common sensor and a spatial profile S_o(x) resulting from measurements made by the first set of sensors.

2. The system set forth in claim 1, wherein the at least one second direction is perpendicular to the first direction.

3. The system set forth in claim 1 or 2, further comprising:

a third set of sensors arranged along at least a third direction that intersects the first direction at a point at which another common sensor (C^xy₁) is placed, said another common sensor belonging to the first and third sets of sensors.

4. The system set forth in any one of claims 1 to 2, wherein the calculation means calculates a speed of the vehicle.

5. The system set forth in any one of claims 1 to 2, further comprising:

a plurality of the first sets of sensors and a plurality of the second sets of sensors arranged in a 2D matrix of sensors.

6. The system set forth in claim 5, wherein the matrix is hollow.

7. The system set forth in any one of claims 1 to 2, further comprising:

at least one second set of sensors, and at least one 2D matrix of sensors arranged on at least one side of the first set of sensors.

8. The system set forth in any one of claims 1 to 2, further comprising:

at least one 1D, or 2D or 3D field sensor or field gradient sensor arranged along a vertical direction.

9. The system set forth in any one of claims 1 to 2, further comprising:

at least one 1D, or 2D or 3D offset field sensor or field gradient sensor.

10. The system set forth in any one of claims 1 to 2, wherein the calculation means forms a spatial representation of the signature of the vehicle.

11. The system set forth in claim 10, wherein the calculation means extracts vehicle identification parameters from said spatial representation.

12. The system set forth in claim 11, wherein the calculation means extracts a length or width of the vehicle by thresholding said spatial representation.

13. The system set forth in claim 11, wherein the calculation means extracts a number of vehicle axles by detection of intensity maxima.

14. The system set forth in claim 11, wherein the calculation means calculates an energy of the signature or at least part of the signature'"'"'s Fourier coefficients.

15. The system set forth in claim 11, further comprising:

a triaxial field sensor,

wherein the calculation means uses an output of the triaxial field sensor to calculate an angle crossed by a magnetic field vector.

16. The system set forth in claim 11, wherein the calculation means calculates a derivative of the signature P(X,Y) along X.

17. The system set forth in claim 16, wherein the calculation means calculates a map of gradients.

18. The system set forth in claim 16, wherein the calculation means calculates a vertical gradient of a magnetic field and a ratio of this gradient to the magnetic field.

19. The system set forth in claim 11, further comprising:

a processor which uses said vehicle identification parameters in a classification algorithm.

20. A system for measuring a magnetic signature of a vehicle, comprising:

at least a first set of sensors (C^x_i) that are stationary and arranged along at least a first direction;

at least a second set of sensors (C^y_j) that are stationary and arranged along at least a second direction that intersects the first direction;

a common sensor (C^xy₀) arranged at a location where the first set of sensors and the second set of sensors intersect, said common sensor belonging to the first and the second sets of sensors,

wherein the first set of sensors and the second set of sensors are arranged so that the vehicle passes above at least part of said first and second set of sensors; and

a processor configured to calculate a relation between a time signature S_o(t) of the vehicle passing above the common sensor and a spatial profile S_o(x) resulting from measurements made by the first set of sensors.