Methods and systems for rapid detection of concealed objects

• US 8,428,217 B2
• Filed: 11/15/2010
• Issued: 04/23/2013
• Est. Priority Date: 09/15/2003
• Status: Expired due to Term

• Current Assignee: Rapiscan Systems Incorporated (OSI Systems Incorporated)
• Original Assignee: Rapiscan Systems Incorporated (OSI Systems Incorporated)
• Inventors: Peschmann, Kristian R.
• Primary Examiner(s): Yun, Jurie
• Application Number:
  US12/946,513
• Publication Number:
  US 20110228896A1
• Time in Patent Office: 890 Days
• Field of Search: 378/4, 378/5, 378/6, 378 44- 46, 378/57, 378 70- 90
• US Class Current: 378/5
• CPC Class Codes: G01N 2223/076 X-ray fluorescence
• CPC Class Codes: G01N 23/20 by using diffraction of the radiation by the materials, e.g. for investigating crystal structure; by using scattering of the radiation by the materials, e.g. for investigating non-crystalline materials; by using reflection of the radiation by the materials
• CPC Class Codes: G01N 23/20083 by using a combination of at least two measurements at least one being a transmission measurement and one a scatter measurement
• CPC Class Codes: G01N 23/223 by irradiating the sample with X-rays or gamma-rays and by measuring X-ray fluorescence
• CPC Class Codes: G01V 5/00 Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity
• CPC Class Codes: G01V 5/222 measuring scattered radiation
• CPC Class Codes: G01V 5/224 Multiple energy techniques using one type of radiation, e.g. X-rays of different energies
• CPC Class Codes: G01V 5/226 using tomography
• CPC Class Codes: G01V 5/228 using stereoscopic means
• CPC Class Codes: G01V 5/281 detecting special nuclear material [SNM], e.g. Uranium-235, Uranium-233 or Plutonium-239

Abstract

This specification is directed towards finding, locating, and confirming threat items and substances. The inspection system is designed to detect objects that are made from, but not limited to, special nuclear materials (“SNM”) and/or high atomic number materials. The system employs a dual energy CT scanning first stage inspection system and advanced image processing techniques to analyze images of an object under inspection (“OUI”), which includes, but is not limited to baggage, parcels, vehicles and cargo.

Claims

1. An apparatus for inspecting an object, comprising:

a first stage inspection system comprising a conveyor for transporting the object into a first inspection volume, a dual energy X-ray source wherein said dual energy X-ray source is configured to irradiate said first inspection volume with dual energy radiation, and a detector array positioned opposite said dual energy X-ray source, configured to receive dual energy radiation transmitted through said object, and adapted to generate signals, comprising high energy data component and low energy data, based upon said received dual energy radiation; and

at least one processor for processing said signals to generate a three dimensional image of said object and to locate a threat within said object and for plotting said high energy data against said low energy data to identify at least one of spectra, parameters of analytical expressions, or spectral attenuation functions in a lookup table.

2. The apparatus of claim 1 wherein said first stage inspection system is adapted to identify a location of the threat within said object and to communicate said location to a human operator.

3. The apparatus of claim 1 wherein said first stage inspection system is adapted to identify a location of the threat within said object and to communicate said location to a second stage inspection system.

4. The apparatus of claim 3 wherein the second stage inspection system inspects said location to confirm the existence of said threat.

5. The apparatus of claim 3 wherein the second stage inspection system produces a second set of data having an X-ray signature characteristic of a material in said location.

6. The apparatus of claim 5 wherein the X-ray signature characteristic is at least one of mass, degree of attenuation, area, atomic number, size, shape, pattern, or context.

7. The apparatus of claim 3 wherein the second stage inspection system determines the existence of said threat by subjecting said object to radiation and detecting at least one of diffracted radiation or scattered radiation.

8. The apparatus of claim 7 wherein the second stage inspection system comprises a detector array having transmission detectors and energy-dispersive detectors.

9. The apparatus of claim 1 wherein said first stage inspection system is adapted to pass said object to a bypass conveyor when said processor determines that said object does not contain a threat.

10. The apparatus of claim 1 wherein said three dimensional image is generated by rotating said dual energy X-ray source and said detector array around said object.

11. The apparatus of claim 1 wherein said processor determines a location by analyzing the three dimensional image and determining a set of coordinates for the location based upon said three dimensional image.

12. The apparatus of claim 11 wherein said analysis comprises computing densities for a plurality of voxels within said three dimensional image.

13. The apparatus of claim 1 wherein said detector array comprises at least one first detector and at least one second detector, wherein said first detector is positioned in front of the second detector relative to a pathway of said transmitted dual energy radiation.

14. The apparatus of claim 13 wherein said first detector is configured to detect more lower energy photons than said second detector.

15. The apparatus of claim 14 wherein said second detector is configured to detect more higher energy photons than said first detector.

16. The apparatus of claim 1 wherein the processor processes said signals to discriminate between pairs of similar materials, wherein said pairs of similar materials comprises at least one pair selected from a) a plastic comprised of more oxygen and nitrogen atoms than hydrogen and carbon atoms and a plastic comprised of more hydrogen and carbon atoms than oxygen and nitrogen atoms and b) a material having more aluminum than steel and a material having more steel than aluminum.

17. An apparatus for inspecting an object, comprising:

a first stage inspection system comprising a conveyor for transporting the object into a first inspection volume, a dual energy X-ray source wherein said dual energy X-ray source is configured to irradiate said first inspection volume with dual energy radiation, and a detector array positioned opposite said dual energy X-ray source, configured to receive dual energy radiation transmitted through said object, and adapted to generate signals, comprising high energy data component and low energy data, based upon said received dual energy radiation;

at least one processor for processing said signals to generate a three dimensional image of said object, to locate a threat within said object, to generate a signal comprising data defining said location and to map said high energy data against said low energy data to identify at least one of spectra, parameters of analytical expressions, or spectral attenuation functions in a lookup table; and

a second stage inspection system comprising a radiation source and a detector array having at least one transmission detector or energy-dispersive detector, wherein said second stage inspection system inspects said object based on said location.

18. The apparatus of claim 17 wherein the second stage inspection system produces a second set of data having an X-ray signature characteristic of a material in said location, wherein the X-ray signature characteristic is at least one of mass, degree of attenuation, area, atomic number, size, shape, pattern, or context.

19. The apparatus of claim 17 wherein said detector array of the first stage inspection system comprises at least one first detector and at least one second detector, wherein said first detector is configured to detect more lower energy photons than said second detector, and wherein said second detector is configured to detect more higher energy photons than said first detector.

20. The apparatus of claim 19 wherein the processor processes said signals to discriminate between pairs of similar materials, wherein said pairs of similar materials comprises at least one pair selected from a) a plastic comprised of more oxygen and nitrogen atoms than hydrogen and carbon atoms and a plastic comprised of more hydrogen and carbon atoms than oxygen and nitrogen atoms and b) a material having more aluminum than steel and a material having more steel than aluminum.