US 2006/0140340 A1Published application

X-ray inspection system for detecting explosives and other contraband

AssigneeControl Screening, LLC

InventorScott Kravis

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Abstract

A baggage scanning system and method employ combined angular and energy dispersive x-ray scanning to detect the presence of a contraband substance within an interrogation volume of a baggage item. The interrogation volume is illuminated with penetrating, polychromatic x-rays in a primary fan beam from a source such as a tungsten-anode x-ray tube. An energy-dependent absorption correction is determined from measurement of the attenuation of the fan beam at a plurality of different energies. Radiation coherently scattered by substances in the interrogation volume is detected by an energy-resolved x-ray detector operated at a plurality of scattering angles to form a plurality of scattering spectra. Each scattering spectrum is corrected for energy-dependent absorption and the corrected spectra are combined to produce a scattering pattern. The experimental scattering pattern is compared with reference patterns that uniquely characterize known contraband substances. The system and method can locate and identify a wide variety of contraband substances in an accurate, reliable manner. The system provides for automated screening, with the result that vagaries of human performance are virtually eliminated. False alarms and the need for hand inspection are reduced and detection efficacy is increased.

Claims26

Dependent claims

A system for screening an interrogation volume within a baggage item for the presence of at least one contraband substance, the system comprising:

a. an x-ray source adapted to emit penetrating, polychromatic radiation;
b. a primary beam collimator adapted to limit the radiation emanating from said x-ray source to a primary fan beam that opens at a fan angle, circumscribes a primary beam direction, and is incident on said interrogation volume;
c. a dual-energy detection system, comprising at least a low-energy x-ray detector and a high-energy x-ray detector, each detector being positioned to intercept and detect radiation in said primary fan beam transmitted through said baggage item;
d. an energy-resolved x-ray detector for detecting radiation coherently scattered from said primary fan beam at a plurality of scattering angles by material within said interrogation volume, material in each portion of said interrogation volume producing scattered radiation detected at each of said plurality of scattering angles;
e. computer means operably associated with said dual-energy detection system and said energy-resolved x-ray detector, said computer means being adapted to:
i. determine an energy-dependent absorption correction from the output of said dual-energy detection system;
ii. produce an energy-resolved scattering spectrum for each of said scattering angles from the output of said energy-resolved x-ray detector;
iii. correct each of said energy-resolved scattering spectra using said energy-dependent absorption correction to produce a corrected spectrum for each of said scattering angles;
iv. combine said corrected spectra to produce a diffraction scattering pattern;
and
v. compare said diffraction scattering pattern with the reference diffraction scattering pattern of at least one known contraband substance stored in said computer means to detect a match indicative of the presence of said known contraband substance in said interrogation volume;
and
f. a signal means associated with said computer means, said signal means being activated in response to the detection of said match.

10 more elements

A method for scanning an interrogation volume within a baggage item to signal the presence of at least one contraband substance, comprising the steps of:

a. illuminating said interrogation volume with a primary fan beam of penetrating, polychromatic radiation, said fan beam opening at a fan angle and circumscribing a primary beam direction;
b. determining an energy-dependent absorption correction for radiation transmitted through said interrogation volume using dual-energy detection;
c. detecting, at a plurality of scattering angles, radiation coherently scattered by material within said interrogation volume to produce an energy-resolved scattering spectrum for each of said scattering angles, said detecting comprising use of at least one energy-resolved x-ray detector and material in each portion of said interrogation volume producing scattered radiation detected at each of said plurality of scattering angles;
d. correcting each of said scattering spectra for absorption using said energy-dependent absorption correction to produce a corrected spectrum for each of said scattering angles;
e. combining said corrected spectra to produce a diffraction scattering pattern;
f. comparing said diffraction scattering pattern with at least one reference diffraction scattering pattern of a known contraband substance to detect a match indicative of the presence of said known contraband substance in said interrogation volume;
and
g. activating a signal means in response to the detection of said match.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/444,492Filed 27 May 2003
Published: 29 Jun 2006
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

G01V 5/222
Active interrogation, i.e. by irradiating objects or goods using external radiation sources, e.g. using gamma rays or cosmic rays: measuring…
G01N 23/20
Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 –…: by…
G01V 5/224
Active interrogation, i.e. by irradiating objects or goods using external radiation sources, e.g. using gamma rays or cosmic rays: multiple energy…
G01V
Geophysics