X-Ray Inspection Based on Scatter Detection

• US 20110075808A1
• Filed: 09/28/2010
• Published: 03/31/2011
• Est. Priority Date: 11/06/2002
• Status: Active Grant

• Current Assignee: American Science and Engineering Incorporated (OSI Systems Incorporated)
• Original Assignee: American Science and Engineering Incorporated (OSI Systems Incorporated)
• Inventors: Schubert, Jeffrey R., Rothschild, Peter J., Schueller, Richard L.
• Granted Patent: US 8,194,822 B2
• Time in Patent Office: Days
• US Class Current: 378/88
• 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: 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
• CPC Class Codes: G01V 5/232 having relative motion between the source, detector and object other than by conveyor G01V5/226 takes precedence
• CPC Class Codes: G01V 5/26 Passive interrogation, i.e. by measuring radiation emitted by objects or goods

Abstract

Systems and methods for inspecting an object with a scanned beam of penetrating radiation. Scattered radiation from the beam is detected, in either a backward or forward direction. Characteristic values of the scattered radiation are compared to expected reference values to characterize the object. Additionally, penetrating radiation transmitted through the inspected object may be combined with scatter information. In certain embodiments, the inspected field of view is less than 0.1 steradians, and the detector is separate from the source of penetrating radiation and is disposed, with respect to the object, such as to subtend greater than 0.5 steradians in the field of view of the object.

Claims

1. A method for inspecting a target object comprising:

a. generating a beam of penetrating radiation with a source of penetrating radiation;

b. collimating the beam of penetrating radiation with a collimator to form a collimated beam;

c. illuminating the target object with the collimated beam;

d. detecting radiation backscattered from the collimated beam by the target object;

e. deriving expected reference values based on reference to portions of the target object;

f. comparing characteristic values of the backscattered radiation to the expected reference values; and

g. determining a descriptive category based on the comparing of which descriptive category characterizes the target object.

2. A method according to claim 1, wherein the penetrating radiation is x-ray radiation.

3. A method according to claim 1, wherein the descriptive category indicates abnormally high metallic content when the characteristic values are less than the expected reference values.

4. A method according to claim 1, wherein the descriptive category indicates abnormally high organic content when the characteristic values are greater than the expected reference values.

5. A method according to claim 1, wherein the descriptive category indicates a potential security threat according to pre-established security threat criteria.

6. A method according to claim 1, wherein the descriptive category indicates a confirmed security threat according to pre-established security threat criteria.

7. A method according to claim 1, further comprising:

selecting a particular target object for illumination.

8. A method according to claim 7, wherein the selecting is based on optical surveillance of an area of interest.

9. A method according to claim 7, wherein the selecting is based on non-optical surveillance of an area of interest.

10. A method according to claim 1, further comprising:

determining the expected reference values based on illuminating a reference object with the penetrating radiation.

11. A method for inspecting an object of inspection with penetrating radiation, the method comprising:

generating a beam of penetrating radiation by means of a concealed source of radiation;

scanning the penetrating radiation across the object;

detecting penetrating radiation transmitted through the object into a concealed transmission detector and generating a transmission signal; and

ascertaining a specified characteristic of the contents of the object based in part on the direct transmission signal.

12. A method according to claim 11, wherein the transmission detector includes one or more linear sections.

13. A method according to claim 11, wherein the transmission detector includes an L-shaped detector with a vertical section and a horizontal section.

14. A method according to claim 11, wherein the transmission detector is incorporated into a speed bump structure.

15. A method according to claim 11, further comprising:

detecting penetrating radiation scattered by the object into a forward scatter detector and generating a forward scatter signal; and

ascertaining a specified characteristic of the contents of the object based in part on the scatter signal.

16. A method according to claim 15, wherein the direct transmission signal and the forward scatter signal are combined to create an enhanced scatter image.

17. A method according to claim 15, wherein the direct transmission signal and the forward scatter signal are combined to create an enhanced transmission image.

18. A method according to claim 16 or 17, further comprising displaying the image to the operator.

19. A method according to claim 15, wherein the forward scatter detector is incorporated into a speed bump structure.

20. A system adapted to use the method according to any of claims 11-19.