CONCEALED OBJECT DETECTION

• US 20070030195A1
• Filed: 05/03/2006
• Published: 02/08/2007
• Est. Priority Date: 09/12/2002
• Status: Abandoned Application

• Current Assignee: L-3 Communications Security & Detection Systems, Inc. (Leidos Holdings, Inc.)
• Original Assignee: L-3 Communications CyTerra Corporation (L3Harris Technologies, Inc.)
• Inventors: Fine, David, Steinway, William, Stilwell, Gregory, Duvoisin, Herbert
• Application Number:
  US11/381,375
• Publication Number:
  US 20070030195A1
• Time in Patent Office: Days
• US Class Current: 342/22
• CPC Class Codes: G01S 13/003 Bistatic radar systems; Multistatic radar systems
• CPC Class Codes: G01S 13/04 Systems determining presence of a target based on relative movement of target G01S13/56
• CPC Class Codes: G01S 13/87 Combinations of radar systems, e.g. primary radar and secondary radar
• CPC Class Codes: G01S 13/887 for detection of concealed objects, e.g. contraband or weapons
• CPC Class Codes: G01S 13/89 for mapping or imaging
• CPC Class Codes: G01S 7/412 based on a comparison between measured values and known or stored values
• CPC Class Codes: G06V 20/52 Surveillance or monitoring of activities, e.g. for recognising suspicious objects recognising microscopic objects G06V20/69
• CPC Class Codes: G06V 2201/05 Recognition of patterns representing particular kinds of hidden objects, e.g. weapons, explosives, drugs

Abstract

A concealed object detection system for detecting objects concealed on a person includes radar transceivers that are each configured and positioned to direct a radar signal at a person and to detect a portion of the radar signal reflected by the person. A processor connected to the radar transceivers processes the portions of the radar signals detected by the radar transceivers to determine whether the person is carrying a concealed object. The system may produce a real-time alert, such as an audible alert, when a concealed object is detected.

Claims

1. An object detection system for detecting objects carried by a person, the system comprising:

radar transceivers that are each configured and positioned to direct a radar signal at a person and including a spiral antenna to detect a portion of the radar signal reflected by the person; and

a processor connected to the radar transceivers and operable to;

process the portions of the radar signals detected by the radar transceivers to conduct a test to determine whether the person is carrying an object to be detected, in which a first characteristic of a first dielectric constant associated with the person is determined from the portions of the radar signals detected by the radar transceivers and a second characteristic of a second dielectric constant associated with the object to be detected is determined from the portions of the radar signals detected by the radar transceivers, and

analyze the portions of the radar signals to output an indication of a detected object.

2. The system of claim 1 wherein the process is operable to analyze the portions of the radar signals in comparison with pre-determined types of items, and, based on the comparison, to output the indication of the detected object.

3. The system of claim 1 wherein a radar tranceiver is operable to output the transmitted radar frequency signal throughout a frequency range of approximately 1.5 to 10 GHz.

4. The system of claim 1 wherein a dielectric constant of the detected object is less than 5.

5. The system of claim 1 wherein the detected object is comprises a plastic or paper material.

6. The system of claim 1 wherein the detected object comprises a metallic object.

7. The system of claim 1 wherein the processor is operable to control the radar transceivers to implement a frequency-stepped radar transmission system.

8. The system of claim 1 wherein:

the radar transceivers are vertically stacked within posts, and

the posts are arranged around a central point.

9. The system of claim 8 wherein the radar transceivers include a vertical beam array and a horizontal beam array for scanning the transmitted radar frequency signal in vertical and horizontal directions about the central point.

10. The system of claim 9 wherein the processor is operable to make a determination that the detected object is in the vicinity of the central point.

11. The system of claim 10 wherein a height of the posts and scanning angles of the detectors are selected to provide a whole-body scan of the person located in the vicinity of the central point.

12. The system of claim 11 wherein the processor is operable to determine a location of the object relative to the person.

13. The system of claim 12 wherein the processor is operable to determine reflectivity measurements associated with a surface reflectivity of the person and clothing of the person.

14. The system of claim 13 wherein a two-dimensional display is created based on the reflectivity measurements.

15. The system of claim 1 wherein the processor is operable to determine whether the object to be detected is being concealed by the person.

16. The system of claim 1 wherein the processor is operable to determine whether the object to be detected is in contact with the person.

17. A method for detecting an object associated with a person, the method comprising:

outputting transmitted radar signals in a direction of a person;

receiving reflected radar signals that are reflected from the person and from an object associated with the person;

determining from the reflected radar signals a first dielectric constant associated with the person;

determining from the reflected radar signals a second characteristic of a second dielectric constant associated with the object; and

analyzing the reflected radar signals portions of the radar signals in comparison with pre-determined types of items, and, based on the comparison, outputting an indication of a detected object.

18. The method of claim 17 further comprising determining reflectivity measurements associated with a surface reflectivity of the person and clothing of the person.

19. The method of claim 18 further comprising:

creating a two-dimensional image of the person based on the reflectivity measurements; and

displaying the two-dimensional image of the person with an indication of an on-body position of the object.

20. The method of claim 17 further comprising determining whether the object associated with the person is being concealed by the person.