Wide area metal detection (WAMD) system and method for security screening crowds

• US 20030080868A1
• Filed: 10/25/2002
• Published: 05/01/2003
• Est. Priority Date: 10/25/2001
• Status: Active Grant

• Current Assignee: Johns Hopkins University
• Original Assignee: Johns Hopkins University
• Inventors: Nelson, Carl V.
• Granted Patent: US 6,970,086 B2
• Time in Patent Office: Days
• US Class Current: 340/551
• CPC Class Codes: G01V 3/104 using several coupled or uncoupled coils G01V3/101 takes precedence

Abstract

A Wide Area Metal Detection (WAMD) system and method for security screening a crowd of people is provided. The system comprises at least one Magnetic Field Generator (MFG), e.g., a Horizontal Magnetic Field Generator (HMFG) buried below a walking surface for generating a magnetic field, a plurality of magnetic field sensors located within the sensing area of the MFG for sensing a metallic object, based on eddy currents in the magnetic field, and a location indicator for indicating a location of an individual with the metallic object at a position corresponding to that of one of the plurality of magnetic field sensor that sensed the metallic object. At least one video camera is included for identifying the individual at the location indicated by the location indicator and tracking further movements of the individual.

Claims

1. A Wide Area Metal Detection (WAMD) system for security screening a crowd of people, the system comprising:

at least one Magnetic Field Generator (MFG) located below a walking surface for generating a magnetic field;

a plurality of magnetic field sensors located within the sensing area of the MFG for sensing a metallic object; and

a location indicator for indicating a location of an individual with the metallic object at a position corresponding to that of one of the plurality of magnetic field sensors that sensed the metallic object.

2. The WAMD system of claim 1, wherein the at least one MFG is a Horizontal Magnetic Field Generator (HMFG).

3. The WAMD system of claim 1, further comprising:

at least one video camera for identifying the individual at the location indicated by the location indicator and tracking further movements of the individual; and

a video display for displaying images captured by the at least one video camera to security personnel.

4. The WAMD system of claim 1, wherein the plurality of magnetic field sensors sense the metallic object by sensing an eddy current generated by the metallic object.

5. The WAMD system of claim 4, further comprising a data processing unit for processing the sensed eddy current to determine whether the metallic object is a possible weapon.

6. The WAMD system of claim 1, wherein the plurality of magnetic field sensors are located below the walking surface.

7. The WAMD system of claim 6, further comprising a non-magnetic surface marked with a grid pattern covering the plurality of magnetic field sensors to assist in locating and apprehending the individual.

8. A Wide Area Metal Detection (WAMD) method for security screening a crowd of people, the method comprising:

directing a traffic pattern of the crowd over at least one Magnetic Field Generator (MFG) and by a plurality of magnetic field sensors;

detecting a presence of a metal object in the crowd utilizing the at least one MFG and one of the plurality of magnetic field sensors;

locating an individual in the crowd with the metal object utilizing a location indicator; and

apprehending the individual to perform a more thorough body search and examine the metal object.

9. The WAMD method of claim 8, further comprising:

identifying the individual in the crowd with at least one video camera, after locating the individual; and

tracking movement of the individual with the at least one video camera until the individual is apprehended.

10. The WAMD method of claim 8, wherein the MFG is a Horizontal Magnetic Field Generator (HMFG).

11. The WAMD method of claim 8, wherein the location indicator locates the individual at a position corresponding to that of the one of the plurality of magnetic field sensors.

12. The WAMD method of claim 8, wherein directing the traffic pattern of the crowd over the at least one MFG is performed using physical barriers.

13. The WAMD method of claim 8, further comprising tracking movement of the individual with the location indicator until the individual is apprehended.

14. The WAMD method of claim 8, wherein the plurality of magnetic field sensors is located below the traffic pattern of the crowd and the at least one MFG and the plurality of magnetic field sensors are covered with a non-magnetic surface including a grid pattern to assist in locating the individual.

15. The WAMD method of claim 8, wherein the one of the plurality of magnetic field sensors detects the metal object by sensing an eddy current generated by the metal object over the at least one MFG.

16. The WAMD method of claim 15, further comprising utilizing the sensed eddy current to determine whether the metal object is a weapon.

17. A Wide Area Metal Detection (WAMD) method for security screening a crowd of people, the method comprising:

directing a traffic pattern of the crowd over at least one Magnetic Field Generator (MFG) and by a plurality of magnetic field sensors;

monitoring the crowd for target individuals, utilizing at least one video camera;

upon identification of a target individual, activating the at least one MFG below the target individual;

determining if a metal object is on the target individual, utilizing the at least one MFG and one of the plurality of magnetic field sensors; and

apprehending the individual to perform a more thorough body search and examine the metal object, if the object is on the target individual.

18. The WAMD method of claim 17, further comprising tracking movement of the individual, utilizing the at least one video camera, until the individual is apprehended.

19. The WAMD method of claim 17, further comprising tracking movement of the individual, utilizing a location indicator, until the individual is apprehended.

20. The WAMD method of claim 17, wherein the plurality of magnetic field sensors is located below the traffic pattern of the crowd and the at least one MFG and the plurality of magnetic field sensors are covered with a non-magnetic surface including a grid pattern to assist in apprehending the individual.

21. The WAMD method of claim 17, wherein the one of the plurality of magnetic field sensors detects the metal object by sensing an eddy current generated by the metal object over the at least one MFG.

22. The WAMD method of claim 21, further comprising utilizing the sensed eddy current to determine whether the metal object is a weapon.

23. The WAMD method of claim 17, wherein the at least one MFG is a Horizontal Magnetic Field Generator (HMFG).