System and method for detecting contraband

• US 20080296501A1
• Filed: 06/04/2007
• Published: 12/04/2008
• Est. Priority Date: 06/04/2007
• Status: Active Grant

• Current Assignee: Morpho Detection (Safran SA)
• Original Assignee: General Electric Company
• Inventors: Breit, Michael, Krug, Florian
• Granted Patent: US 7,888,646 B2
• Time in Patent Office: Days
• US Class Current: 250/341.8
• CPC Class Codes: G01J 3/42 Absorption spectrometry; Double beam spectrometry; Flicker spectrometry; Reflection spectrometry beam switching arrangements G01J3/08
• CPC Class Codes: G01N 21/3563 for analysing solids; Preparation of samples therefor
• CPC Class Codes: G01N 21/3581 using far infrared light; using Terahertz radiation
• CPC Class Codes: G01N 21/55 Specular reflectivity

Abstract

A technique is provided for detecting whether an object of interest is being carried by a subject. The technique includes coarsely scanning the subject with an electromagnetic radiation, measuring reflective intensity of radiation reflected from the subject, and detecting the presence or absence of the object of interest based upon the measured reflective intensity.

Claims

1. A method for detecting whether an object of interest is being carried by a subject, the method comprising:

coarsely scanning the subject with an electromagnetic radiation;

measuring reflective intensity of radiation reflected from the subject; and

detecting the presence or absence of the object of interest based upon the measured reflective intensity.

2. The method of claim 1, wherein said coarsely scanning comprises coarsely scanning with an electromagnetic radiation in a range of about 0.1 terahertz to about 10 terahertz.

3. The method of claim 1, wherein said coarsely scanning comprises scanning the subject with an electromagnetic radiation having a spot size of at least 1 centimeter at a predetermined scanning distance.

4. The method of claim 3, wherein the spot size is at least five centimeters at the scanning distance.

5. The method of claim 3, wherein the spot size is more than 15 centimeters at the scanning distance.

6. The method of claim 1, wherein said coarsely scanning the subject comprises scanning the subject at multiple frequencies of the electromagnetic radiation.

7. The method of claim 6, wherein each of the multiple frequencies is selected based upon a known spectroscopic signature of the object of interest.

8. The method of claim 6, wherein said coarsely scanning comprises switching between the multiple frequencies at a rate faster than the coarse scanning rate.

9. The method of claim 1, wherein the electromagnetic radiation is in a range of about 10 gigahertz to 100 gigahertz.

10. The method of claim 9, wherein said detecting the presence of the object of interest comprises identifying a region of interest within the subject and scanning the region of interest at multiple frequencies of the electromagnetic radiation in the terahertz range to detect the object of interest.

11. The method of claim 1, wherein said detecting the presence or absence of the object of interest comprises detecting the presence or absence of a spectroscopic signature of the object of interest from the measured reflective intensity.

12. The method of claim 1, wherein the object of interest includes an explosive material and wherein said detecting the presence or absence of the object of interest is based upon a spectroscopic signature of the explosive material.

13. The method of claim 1, wherein said coarsely scanning the subject comprises scanning the subject continuously or scanning the subject intermittently.

14. A method for detecting a presence or absence of an object of interest, the method comprising:

coarsely scanning a region of interest with an electromagnetic radiation in the terahertz range while selecting different frequencies of the electromagnetic radiation, the electromagnetic radiation having a spot size of at least 1 centimeter at a predetermined scanning distance;

measuring reflective intensity of radiation reflected from the scanned region; and

detecting the presence or absence of the object of interest within the region of interest based upon the measured reflective intensity.

15. The method of claim 14, comprising coarsely scanning a region with an electromagnetic radiation in a range of about 10 gigahertz to about 100 gigahertz to identify the region of interest within the region.

16. The method of claim 14, wherein said detecting the presence or absence of the object of interest comprises detecting the presence or absence of a spectroscopic signature of the object of interest from the measured reflective intensity.

17. The method of claim 14, wherein the spot size is at least five centimeters at the scanning distance.

18. The method of claim 14, wherein the spot size is more than 15 centimeters at the scanning distance.

19. The method of claim 14, wherein each of the selected different frequencies is based upon a known spectroscopic signature of the object of interest.

20. A system for detecting whether an object of interest is being carried by a subject, the system comprising:

a source configured to generate electromagnetic radiation in terahertz range;

an optical scanner configured to coarsely scan a region of interest within the subject with the generated electromagnetic radiation; and

a detection subsystem configured to detect radiation reflected from the scanned region, measure reflective intensity of the reflected radiation, and detect the presence or absence of the object of interest within the region of interest based upon the measured reflective intensity.

21. The system of claim 20, wherein the source comprises a backward wave oscillator source, a quantum cascading laser source, a multiplier chain source, a gas laser source, or other sweepable ultra-broadband high-power source.

22. The system of claim 20, wherein the source is configured to generate electromagnetic radiation at multiple frequencies in the terahertz range and wherein the optical scanner is configured to coarsely scan the region of interest at the multiple frequencies of the electromagnetic radiation.

23. The system of claim 22, wherein each of the multiple frequencies is selected based upon a known spectroscopic signature of the object of interest.

24. The system of claim 22, wherein the source is configured to switch between the multiple frequencies at a rate faster than the coarse scanning rate of the optical scanner.

25. The system of claim 20, wherein the optical scanner is configured to scan the region of interest with the electromagnetic radiation having a spot size of at least 1 centimeter at a predetermined scanning distance.

26. The system of claim 25, wherein the spot size is at least five centimeters at the scanning distance.

27. The system of claim 25, wherein the spot size is more than 15 centimeters at the scanning distance.

28. The system of claim 20, wherein the optical scanner is configured to coarsely scan the region of interest continuously.

29. The system of claim 20, wherein the detection subsystem comprises a Golay cell broadband detector, a cryogenically cooled bolometer, an antenna coupled bolometer, a pyroelectric broadband detector, or other broadband detectors.

30. The system of claim 20, wherein the detection subsystem is configured to detect the presence of the object of interest by detecting the presence of spectroscopic signature of the respective object of interest from the measured reflective intensity.

31. The system of claim 20, wherein the detector subsystem is synchronized with the source to enable frequency dependent detection.

32. The system of claim 20, further comprising another source for generating electromagnetic radiation in a range of about 10 gigahertz to about 100 gigahertz.

33. The system of claim 32, wherein the optical scanner is configured to coarsely scan the subject with the electromagnetic radiation in the range of about 10 gigahertz to about 100 gigahertz to identify the region of interest.