Methods and systems for the rapid detection of concealed objects

• US 7,579,845 B2
• Filed: 07/18/2008
• Issued: 08/25/2009
• Est. Priority Date: 09/15/2003
• Status: Expired due to Fees

• Current Assignee: Rapiscan Systems Incorporated (OSI Systems Incorporated)
• Original Assignee: Rapiscan Security Products USA Incorporated (OSI Systems Incorporated)
• Inventors: Mann, Kenneth Robert, Peschmann, Kristian R.
• Primary Examiner(s): Nguyen; Vincent Q
• Assistant Examiner(s): ZHU, JOHN X
• Application Number:
  US12/175,599
• Publication Number:
  US 20090041187A1
• Time in Patent Office: 403 Days
• Field of Search: 324/637, 324/638, 324/639, 324/342, 250/582, 250/250
• US Class Current: 324/637
• CPC Class Codes: G01F 23/284 Electromagnetic waves
• CPC Class Codes: G01N 22/00 Investigating or analysing materials by the use of microwaves or radio waves, i.e. electromagnetic waves with a wavelength of one millimetre or more G01N3/00 - G01N17/00, G01N24/00 take precedence
• CPC Class Codes: G01R 27/06 Measuring reflection coefficients; Measuring standing-wave ratio
• CPC Class Codes: G01V 5/22 Active interrogation, i.e. by irradiating objects or goods using external radiation sources, e.g. using gamma rays or cosmic rays
• CPC Class Codes: G01V 5/222 measuring scattered radiation

Abstract

The present invention provides for an improved scanning process having microwave arrays comprised of microwave transmitters in radiographic alignment with microwave receivers. The microwave array emits controllably directed microwave radiation toward an object under inspection. The object under inspection absorbs radiation in a manner dependent upon its metal content. The microwave radiation absorption can be used to generate a measurement of metal content. The measurement, in turn, can be used to calculate at least a portion of the volume and shape of the object under inspection. The measurement can be compared to a plurality of predefined threats. The microwave screening system is used in combination with other screening technologies, such as NQR-based screening, X-ray transmission based screening, X-ray scattered based screening, or Computed Tomography based screening.

Claims

1. A method of scanning an object, comprising the steps of:

subjecting said object to a first screening system comprising microwave arrays, wherein said microwave arrays comprise more than one microwave transmitter and more than one microwave receiver, wherein the microwave transmitters and microwave receivers are separated by an inspection region, and wherein each of said microwave transmitters transmits microwave radiation to more than one microwave receivers and wherein the first screening system comprises a data acquisition system that acquires data from said microwave receivers, said data comprising microwave radiation absorption data; and

subjecting said object to a second screening system selected from any one of NQR-based screening, X-ray transmission based screening, X-ray scattered based screening, or Computed Tomography based screening.

2. The method of claim 1 wherein said first screening system operates concurrent with said second screening system.

3. The method of claim 1 wherein said first screening system operates serially with respect to said second screening system.

4. The method of claim 1 wherein said microwave transmitter emits controllably directed microwave radiation toward an object under inspection wherein said object under inspection absorbs radiation in a manner dependent upon its metal content.

5. The method of claim 4 wherein said microwave radiation absorption data can be used to generate a measurement of metal content.

6. The method of claim 5 wherein the object under inspection is selected for screening by said second screening system if the measurement is different than a pre-defined value.

7. The method of claim 5 wherein the measurement can be compared to a plurality of predefined threats.

8. The method of claim 5 wherein the object under inspection is ignored by a system operator if the measurement is different than a pre-defined value.

9. The method of claim 5 wherein the measurement is used to generate a microwave image.

10. The method of claim 5 wherein the measurement is used to generate a microwave image and the microwave image is combined with an image produced by said second screening system.

11. The method of claim 5 wherein the measurement is used to generate positional information of metal content in the object under inspection.

12. The method of claim 11 wherein the positional information of metal content is used to direct an analysis from material specific detection technology.

13. The method of claim 12 wherein said material specific detection technology is selected from any one of x-ray diffraction, thermal neutron analysis or pulsed fast neutron analysis.

14. The method of claim 1 wherein the microwave transmitters and microwave receivers are configured in a manner that replicates X-ray beam fan beam geometry.

15. The method of claim 1 wherein the microwave transmitters and microwave receivers are configured in a manner that replicates X-ray beam folded array geometry.

16. The method of claim 1 wherein the microwave transmitters and microwave receivers are configured in a manner that replicates Computed Tomography array geometry.

17. The method of claim 1 wherein the microwave transmitters are broad beam transmit antennas.

18. The method of claim 1 wherein the microwave receivers are narrow band receive antennas.

19. The method of claim 1 wherein said broad beam transmit antennas are configured in parallel with said narrow band receive antennas and switched such that each transmit antenna transmits to several receive antennas.

20. The method of claim 1 wherein said switching occurs to move an illumination point around a region.