MAGNETIC TRAFFIC CONTROL SYSTEM

• US 20070162218A1
• Filed: 01/04/2007
• Published: 07/12/2007
• Est. Priority Date: 01/11/2006
• Status: Active Grant

• Current Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Original Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Inventors: Blanpain, Roland, Guilhamat, Bernard, Cattin, Viviane, Flament, Bruno
• Granted Patent: US 7,765,056 B2
• Time in Patent Office: Days
• 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

The invention relates to a device for measuring the magnetic signatures of vehicles including:

• • at least a first set of sensors (C^x_i), designed to be arranged along at least a first direction (2),
  • at least a second set of sensors (C^y_j), designed to be arranged along at least a second direction (4), that intersects the first direction at a point at which a common sensor (C^xy₀) is placed, belonging to the first and the second set,
  • calculation means to calculate a relation between the time signature S_o(t) of a vehicle passing above the common sensor and a spatial profile S_o(x) resulting from measurements made by the sensors in the first set of sensors.

Claims

1. Device for measuring the magnetic signatures of vehicles including:

at least a first set of sensors (C^x_i) designed to be arranged along at least a first direction (2),

at least a second set of sensors (C^y_j), designed to be arranged along at least a second direction (4), that intersects the first direction at a point at which a common sensor (C^xy₀) is placed, belonging to the first and the second set,

calculation means (50) to calculate a relation between the time signature S_o(t) of a vehicle passing above the common sensor and a spatial profile S_o(x) resulting from measurements made by the sensors in the first set of sensors.

2. Device set forth in claim 1, at least one second direction being perpendicular to the first direction.

3. Device set forth in claim 1 or 2, including a third set of sensors designed to be arranged along at least a third direction, that intersects the first direction at a point at which a common sensor (C^xy₁) is placed, belonging to the first and third set.

4. Device set forth in any one of claims 1 to 3, the calculation means being also used to calculate the vehicle speed.

5. Device set forth in any one of claims 1 to 4, including a plurality of first sets of sensors and a plurality of second sets of sensors forming a 2D matrix of sensors.

6. Device set forth in claim 5, the matrix being hollow.

7. Device set forth in any one of claims 1 to 4, including a first set of sensors, at least one second set of sensors, and at least one 2D matrix of sensors arranged on at least one of the sides of the first set.

8. Device set forth in any one of claims 1 to 7, also including at least one 1D, or 2D or 3D field sensor or field gradient sensor along the vertical direction.

9. Device set forth in any one of claims 1 to 8, including at least one 1D, or 2D or 3D offset field sensor or field gradient sensor.

10. Device set forth in any one of claims 1 to 9, the calculation means being used to form a spatial representation of the signature of vehicles.

11. Device set forth in claim 10, the calculation means being used to extract vehicle identification parameters from said spatial representation.

12. Device set forth in claim 11, the calculation means being used to extract the length and/or the width of the vehicle by thresholding said spatial representation.

13. Device set forth in claim 11 or 12, the calculation means being used to extract the number of vehicle axles by detection of intensity maxima.

14. Device set forth in any one of claims 11 to 13, the calculation means being used to calculate the energy of the signature and/or at least part of its Fourier coefficients.

15. Device set forth in any one of claims 11 to 14, also including a triaxial field sensor, the calculation means being used to calculate the angle crossed by the magnetic field vector.

16. Device set forth in any one of claims 11 to 15, the calculation means being used to calculate the derivative of the signature P(X,Y) along X.

17. Device set forth in claim 16, the calculation means being used to calculate a map of gradients.

18. Device set forth in claim 16 or 17, the calculation means being used to calculate a vertical gradient of the field and the ratio of this gradient to the field.

19. Device set forth in any one of claims 11 to 18, said parameters being used in a classification algorithm.