System and method for inspecting containers for target material

• US 7,839,971 B2
• Filed: 12/31/2007
• Issued: 11/23/2010
• Est. Priority Date: 12/31/2007
• Status: Active Grant

• Current Assignee: Morpho Detection (Safran SA)
• Original Assignee: Morpho Detection (Safran SA)
• Inventors: Gu, Mengqian, Bendahan, Joseph, Garms, Walter Irving
• Primary Examiner(s): Glick; Edward J
• Assistant Examiner(s): Sanei; Mona M
• Application Number:
  US12/006,119
• Publication Number:
  US 20090168949A1
• Time in Patent Office: 1,058 Days
• Field of Search: 378/57
• US Class Current: 378/57
• CPC Class Codes: G01N 2223/419 computed tomograph
• CPC Class Codes: G01N 2223/424 energy substraction image processing (dual energy processing)
• CPC Class Codes: G01N 2223/639 material in a container
• CPC Class Codes: G01N 23/046 using tomography, e.g. computed tomography [CT]
• 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 5/232 having relative motion between the source, detector and object other than by conveyor G01V5/226 takes precedence

Abstract

A method for automatically inspecting a container for a target material using a computed tomography (CT) scanning system includes performing an initial radiographic scan of the container. Based at least partially on projection data generated during the initial radiographic scan, at least one location within the container is identified that requires CT inspection. A dual energy CT scan of the at least one identified location within the container is performed based on a single energy algorithm or a dual energy algorithm. The dual energy CT scan includes a low energy scan of the at least one identified location and a high energy scan of the at least one identified location. Based on dual energy scan information generated during the dual energy CT scan, a determination is made to confirm or clear an alarm corresponding to the at least one identified location within the container.

Claims

1. A method for automatically inspecting a container for a target material using a computed tomography (CT) scanning system, said method comprising:

performing an initial radiographic scan of the container;

identifying, based at least partially on projection data generated during the initial radiographic scan, a first slice plan with at least one location within the container that requires CT inspection;

performing additional single energy scans to acquire additional projection data;

adjusting the first slice plan using the additional projection data;

identifying at least one object of interest using an automatic detection algorithm once the first slice plan requires no more single energy scans;

if the at least one object of interest is identified, generating a second slice plan of the at least one object of interest;

performing a dual energy CT scan of the at least one object of interest, the dual energy CT scan including a low energy scan of the at least one object of interest and a high energy scan of the at least one object of interest;

determining, based at least partially on dual energy scan information generated during the dual energy CT scan, whether the at least one object of interest includes a target material; and

generating an alarm signal for the container if the at least one object of interest includes the target material.

2. A method in accordance with claim 1, wherein performing a dual energy CT scan comprises calculating a CT number distribution within cross-sectional slices of the container and processing the dual energy scan information to determine an atomic number distribution to facilitate identifying the at least one object of interest within the container.

3. A method in accordance with claim 2, further comprising CT scanning only the at least one object of interest to facilitate maintaining system throughput.

4. A method in accordance with claim 1, wherein said performing a dual energy CT scan is based on the single energy algorithm, said method further comprising generating a single energy slice plan using first high energy scan information obtained during the dual energy CT scan, the first high energy scan information utilized to facilitate determining whether the at least one identified location includes the at least one object of interest.

5. A method in accordance with claim 4, further comprising performing a second dual energy CT scan of the at least one identified location to generate second high energy scan information utilized to facilitate identifying the at least one object of interest.

6. A method in accordance with claim 5, wherein said method further comprises determining based on the dual energy scan information whether to generate the alarm signal or to clear the container.

7. A method in accordance with claim 6, further comprising:

generating the alarm signal;

performing a post detection dual energy CT scan of the at least one object of interest; and

determining whether to clear an alarm based on information obtained during the post detection dual energy CT scan.

8. A method in accordance with claim 7, wherein during the post detection dual energy CT scan, high energy scan information related to a CT number of the at least one object of interest and a combination of the high energy scan information and low energy scan information related to an atomic number of the at least one object of interest are processed to determine whether the at least one object of interest includes the target material.

9. A method in accordance with claim 1, further comprising:

determining that the at least one identified location includes the at least one object of interest; and

performing a CT scan to facilitate determining whether the at least one object of interest includes the target material.

10. A method in accordance with claim 9, further comprising:

generating high energy scan information and low energy scan information corresponding to additional cross-sectional slices of the identified location; and

transmitting to a data collection system the high energy scan information and the low energy scan information, the data collection system configured to calculate a CT number distribution and an atomic number distribution within the additional cross-sectional slices of the identified location to facilitate identifying the target material within the identified location.

11. A method in accordance with claim 1, further comprising:

generating the first slice plan to scan the identified locations for objects having a CT number similar to a CT number of the target material; and

performing a single energy CT scan of the container based on a single energy algorithm.

12. A method in accordance with claim 11, further comprising transmitting high energy scan information obtained during the single energy CT scan to a data collection system, the data collection system configured to calculate a CT number distribution within cross-sectional slices of the container to facilitate identifying the at least one object of interest within the container.

13. A method in accordance with claim 12, wherein the dual energy CT scan is performed only on the at least one object of interest.

14. A method in accordance with claim 11, further comprising generating a single energy slice plan using high energy scan information obtained during the single energy CT scan, the high energy scan information including CT number information utilized to facilitate determining whether the identified location includes the at least one object of interest.

15. A method in accordance with claim 14, further comprising bypassing the dual energy CT scan if no object of interest is identified based on the high energy scan information obtained during the single energy CT scan.

16. A method in accordance with claim 14, wherein, upon identifying the at least one object of interest, the dual energy CT scan is performed to facilitate determining whether the at least one object of interest includes the target material.

17. A method in accordance with claim 1, further comprising generating the alarm signal before performing the dual energy CT scan, wherein the dual energy CT scan only scans identified locations within the container suspected of including at least one object of interest.

18. A method in accordance with claim 17, wherein performing a dual energy CT scan of the at least one identified location further comprises obtaining high energy scan information corresponding to a CT number of the at least one object of interest and a combination of the high energy scan information and low energy scan information corresponding to an atomic number of the object of interest to facilitate determining whether the at least one object of interest includes the target material.

19. A method in accordance with claim 18, further comprising removing the container from the CT scanning system for further inspection if, based on the high energy scan information and the low energy scan information, the at least one object of interest includes the target material.

20. A method in accordance with claim 18, further comprising determining whether an additional alarm signal was generated for the container during the dual energy CT scan.

21. A method in accordance with claim 20, further comprising ejecting the container from within the CT scanning system if no additional alarm signal is generated.

22. A method in accordance with claim 20, further comprising performing a second dual energy CT scan if the additional alarm signal was generated for the container during the dual energy CT scan.

23. A method in accordance with claim 22, further comprising ejecting the container from within the CT scanning system if, upon scanning at least one object of interest responsible for generating the alarm signal, no object of interest includes the target material.

24. A method in accordance with claim 17, further comprising performing a query to determine whether a second container is queued for scanning.

25. A method in accordance with claim 24, wherein, if scanning of the container generates the alarm signal and the second container is queued for scanning by the CT scanning system, the container is ejected from within the CT scanning system for further inspection.

26. A method in accordance with claim 24, wherein, if scanning of the container generates the alarm signal and the second container is not queued for scanning, the dual energy CT scan of alarming objects within the container is performed.

27. A computed tomography (CT) scanning system for automatically inspecting a container for a target material, said CT scanning system comprising:

an X-ray source;

an X-ray detector; and

a processor, said processor configured to;

perform an initial radiographic scan of the container;

identify, based at least partially on projection data generated during the initial radiographic scan, a first slice plan with at least one location within the container that requires a single energy CT inspection;

adjust the first slice plan as additional single energy scans are performed;

identify objects of interest using an automatic detection algorithm once the first slice plan requires no more single energy scans;

if at least one object of interest is identified, generate a second slice plan of the at least one object of interest;

perform a dual energy CT scan of the at least one identified object of interest, the dual energy CT scan comprising a low energy scan of the at least one identified object of interest and a high energy scan of the at least one identified object of interest;

determine whether the at least one object of interest includes a target material based at least partially on dual energy scan information generated during the dual energy CT scan; and

generate an alarm signal for the container if the at least one object of interest includes the target material.

28. A method for automatically inspecting containers for a target material using a computed tomography (CT) scanning system, said method comprising:

identifying at least one location within a first container that requires CT inspection based at least partially on projection data generated during an initial radiographic scan;

performing a dual energy CT scan of the at least one identified location within the first container, the dual energy CT scan including a low energy scan of the at least one identified location and a high energy scan of the at least one identified location;

determining whether the at least one identified location includes an object of interest based on data acquired by the dual energy CT scan;

when the at least one identified location includes the object of interest, generating an alarm;

determining whether a second container is queued for scanning;

when the second container is queued for scanning, ejecting the first container from within the CT scanning system for further inspection to determine if the object of interest includes the target material; and

when the second container is not queued for scanning, performing a dual energy CT scan of the object of interest within the first container to determine if the object of interest includes the target material.