Apparatus and method for detecting threats

• US 7,260,173 B2
• Filed: 02/25/2003
• Issued: 08/21/2007
• Est. Priority Date: 11/25/2002
• Status: Expired due to Fees

• Current Assignee: Hitachi Engineering & Services Company Limited (Hitachi, Ltd.), Hitachi, Ltd.
• Original Assignee: Hitachi Engineering & Services Company Limited (Hitachi, Ltd.), Hitachi, Ltd.
• Inventors: Okada, Hidehiro, Wakayama, Kyoichiro, Hattori, Yukiya, Koshishiba, Hiroya
• Primary Examiner(s): Glick; Edward J.
• Assistant Examiner(s): Artman; Thomas R.
• Application Number:
  US10/372,393
• Publication Number:
  US 20040101097A1
• Time in Patent Office: 1,638 Days
• Field of Search: 378/57, 378/19
• US Class Current: 378/19
• CPC Class Codes: G01N 2223/419 computed tomograph
• CPC Class Codes: G01N 23/046 using tomography, e.g. computed tomography [CT]
• CPC Class Codes: G01V 5/226 using tomography

Abstract

An image pickup unit is disposed so as to be able to obtain a scan projection image of an inspection subject from each of a vertical direction and a horizontal direction. An X-ray absorption coefficient of an object in the inspection subject is obtained from the vertical scan projection image and the horizontal scan projection image. It is determined whether there is a threat in the inspection subject on the basis of the X-ray absorption coefficient. Furthermore, a CT image is obtained by moving the image pickup unit around the inspection subject. It is determined whether there is a threat in the inspection subject, on the basis of the CT values of the CT image.

Claims

1. A hazardous material detection system comprising:

a gantry provided with an X-ray source and an X-ray sensor which are disposed in opposition to each other, wherein the X-ray source comprises a cable for supplying power and the X-ray sensor comprises a cable for outputting a signal and wherein the gantry swings forward and backward on a circular arc around an inspection subject but does not continuously rotate;

a belt-conveyor which conveys the inspection subject wherein the belt-conveyor comprises a first conveyor in front of the gantry and a second belt-conveyor in rear of the gantry;

a calculating unit which calculates a computed tomography (CT) value by swinging the gantry forward and backward along the circular arc around the inspection subject along said circular arc and picking up a CT image of the inspection subject; and

a display unit which displays the X-ray absorption coefficient and the CT value,

wherein the CT image is obtained by use of a particular configuration of the gantry which allows the gantry to rotate at least 330 degrees.

2. A method for detecting hazardous material, wherein a gantry is provided with an X-ray source and an X-ray sensor which are disposed in opposition to each other, the X-ray source comprises a cable for supplying power and the X-ray sensor comprises a cable for outputting a signal, and the gantry swings forward and backward on a circular arc around an inspection subject but does not continuously rotate, the method comprising the steps of:

conveying an inspection subject by moving a belt-conveyor comprising a first belt-conveyor in front of the gantry and a second belt-conveyor in rear of the gantry, and then stopping the belt-conveyor if the inspection subject is positioned between the first belt-conveyor and the second belt-conveyor;

swinging the gantry forward and backward along the circular arc while an X-ray is being radiated from the X-ray source;

obtaining a computed tomography (CT) image based on an X-ray radioscopy data obtained by the X-ray sensor,

wherein the CT image is obtained by use of a particular configuration of the gantry which allows the gantry to rotate at least 330 degrees; and

displaying the CT image on a display device.