System and method for analyzing content data

• US 7,430,479 B1
• Filed: 08/01/2005
• Issued: 09/30/2008
• Est. Priority Date: 08/17/2004
• Status: Expired due to Fees

• Current Assignee: Leidos, Inc. (Leidos Holdings, Inc.)
• Original Assignee: Science Applications International Corporation
• Inventors: Borgonovi, Giancarlo, Holslin, Daniel
• Primary Examiner(s): TSAI, CAROL S W
• Application Number:
  US11/193,529
• Time in Patent Office: 1,156 Days
• Field of Search: 702/19, 702/22, 702/27, 702/28, 702/30, 702/32, 702/40, 702/23, 702/31, 702/124, 702/183, 702/188, 702/189, 250/390.04, 250/358.1, 250/356.2, 250/390.07, 250/390.02, 250/359.1, 250/393, 376/158, 376/159, 376/165, 376/166
• US Class Current: 702/22
• CPC Class Codes: G01T 1/167 Measuring radioactive content of objects, e.g. contamination whole body counters G01T1/163
• CPC Class Codes: G01T 3/00 Measuring neutron radiation G01T5/00 takes precedence
• CPC Class Codes: G01V 5/20 Detecting prohibited goods, e.g. weapons, explosives, hazardous substances, contraband or smuggled objects
• CPC Class Codes: G01V 5/234 Measuring induced radiation, e.g. thermal neutron activation analysis

Abstract

The system and method provide security and cargo handling personnel a versatile tool to rapidly check cargo for hidden radiological materials, explosives, drugs, and chemical weapons material. Gamma ray emission is stimulated by a pulsed neutron source. The gamma ray signature is used to classify the material. Passive gamma ray analysis can be used to detect and identify radiological material. The method of determining the contents of a target includes irradiating a target; detecting at least one spectrum emitted from the target; performing a primary analysis to extract a first set of indicators; and performing a secondary analysis to decide the contents of the target. The primary analysis utilizes either a least squares analysis or principal component analysis. The secondary analysis utilizes a generalized likelihood ratio test or support vector machines.

Claims

1. A method for analyzing target interrogation data, the method comprising:

irradiating a target with neutrons;

collecting target interrogation data, wherein the target interrogation data comprises spectra that is representative of the contents of the target;

performing a primary analysis of the spectra according to a least squares analysis to determine a first set of elemental intensities representative of the contents of the target;

performing a secondary analysis of the spectra utilizing the first set of elemental intensities by comparing the first set of elemental intensities from the target to a second set of elemental intensities for known spectra wherein the secondary analysis is a tertiary hypothesis test; and

classifying the contents of the target based on the secondary analysis comparison.

2. The method according to claim 1, wherein classifying the target further comprises the step of determining whether the target contains explosives, chemical warfare agents, or illicit drugs.

3. The method according to claim 1, wherein spectra is emitted from at least one element of the target selected from the group consisting of H, C, N, O, S, Cl, Fe, Al, Si, and P.

4. The method according to claim 1, further comprising the step of providing a library of spectra for at least one element.

5. The method according to claim 1, further comprising the step of plotting a receiver operating characteristic curve.

6. The method according to claim 1, wherein the spectra are gamma ray spectra.

7. A method for analyzing target interrogation data, the method comprising:

irradiating a target with neutrons;

collecting target interrogation data, wherein the target interrogation data comprises spectra that is representative of the contents of the target;

performing a primary analysis of the spectra according to a principal component analysis to determine a first set of vectors representative of the contents of the target;

performing a secondary analysis of the spectra utilizing the first set of vectors by comparing the first set of vectors from the target to a second set of vectors for known spectra; and

classifying the contents of the target based on the secondary analysis comparison.

8. The method according to claim 7, wherein the secondary analysis is a generalized likelihood ratio test or support vector machines.

9. The method according to claim 7, wherein classifying the target further comprises the step of determining whether the target contains explosives, chemical warfare agents, or illicit drugs.

10. The method according to claim 7, wherein spectra is emitted from at least one element of the target selected from the group consisting of H, C, N, O, S, Cl, Fe, Al, Si, and P.

11. The method according to claim 7, further comprising the step of plotting a receiver operating characteristic curve.

12. The method according to claim 7, wherein the secondary analysis is a binary hypothesis test.

13. The method according to claim 7, wherein the secondary analysis is a tertiary hypothesis test.

14. The method according to claim 7, wherein the spectra are gamma ray spectra.

15. An interrogation system for determining the contents of a target comprising:

at least one pulsed neutron generator;

at least one detector configured to provide spectra representative of the target;

a primary analysis application to perform a least squares analysis of the spectra to determine a first set of elemental intensities representative of the contents of the target; and

a secondary analysis application to perform an analysis of the spectra utilizing the first set of elemental intensities by comparing the first set of elemental intensities from the target to a second set of elemental intensities for known spectra wherein the secondary analysis is a tertiary hypothesis test;

wherein the system classifies the contents of the target based on the secondary analysis application comparison.

16. The interrogation system according to claim 15, wherein the system classifies the target to determining whether the target contains explosives, chemical warfare agents, or illicit drugs.

17. The interrogation system according to claim 15, wherein spectra is emitted from at least one element of the target selected from the group consisting of H, C, N, O, S, Cl, Fe, Al, Si, and P.

18. The interrogation system according to claim 15, further comprising a library of spectra for at least one element.

19. The system according to claim 15, wherein the secondary analysis application plots a receiver operating characteristic curve.

20. The system according to claim 15, wherein the spectra are gamma ray spectra.

21. An interrogation system for determining the contents of a target comprising:

at least one pulsed neutron generator;

at least one detector configured to provide spectra representative of the target;

a primary analysis application to perform a principal component analysis to determine a first set of vectors representative of the contents of the target; and

a secondary analysis application to perform an analysis of the spectra utilizing the first set of vectors be comparing the first set of vectors from the target to a second set of vectors for known spectra;

wherein the system classifies the contents of the target based on the secondary analysis application comparison.

22. The interrogation system according to claim 21, wherein the secondary analysis application utilizes a generalized likelihood ratio test or support vector machines.

23. The interrogation system according to claim 21, wherein the system classifies the target to determining whether the target contains explosives, chemical warfare agents, or illicit drugs.

24. The interrogation system according to claim 21, wherein spectra is emitted from at least one element of the target selected from the group consisting of H, C, N, O, S, Cl, Fe, Al, Si, and P.

25. The interrogation system according to claim 21, wherein the secondary analysis application plots a receiver operating characteristic curve.

26. The interrogation system according to claim 21, wherein the secondary analysis application utilizes a binary hypothesis test.

27. The interrogation system according to claim 21, wherein the secondary analysis utilizes a tertiary hypothesis test.

28. The system according to claim 21, wherein the spectra are gamma ray spectra.