Apparatus and method for detecting threats

• US 20040101097A1
• Filed: 02/25/2003
• Published: 05/27/2004
• Est. Priority Date: 11/25/2002
• Status: Active Grant

• 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
• Granted Patent: US 7,260,173 B2
• Time in Patent Office: Days
• US Class Current: 378/57
• 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 threat detection system comprising:

an image pickup device disposed so as to be able to pick up a scan projection image of an inspection subject from a first direction and a second direction;

a computation unit for computing an X-ray absorption coefficient of an object contained in the inspection subject on the basis of a first scan projection image picked up from the first direction by the image pickup device and a second scan projection image picked up from the second direction by the image pickup device;

a storage unit for retaining a database of X-ray absorption coefficients of threats;

a decision unit for making a decision as to whether the computed X-ray absorption coefficient is included in the database; and

a display unit for displaying the first scan projection image or the second scan projection image together with a result of the decision.

3. A threat detection system according to claim 1, wherein the image pickup device comprises an X-ray tube and a line sensor disposed so as to be opposed to a gantry that can move in a circular arc form.

2. A threat detection system comprising:

an image pickup device disposed so as to be able to pick up a scan projection image of an inspection subject from a first direction and a second direction;

a first computation unit for computing an X-ray absorption coefficient of an object contained in the inspection subject on the basis of a first scan projection image picked up from the first direction by the image pickup device and a second scan projection image picked up from the second direction by the image pickup device;

a storage unit for retaining a database of X-ray absorption coefficients and CT values of threats;

a decision unit for making a decision as to whether the X-ray absorption coefficient of the object is included in the database; and

a second computation unit responsive to a decision that the X-ray absorption coefficient of the object is included in the database, for moving the image pickup device around the fixed inspection subject and computing CT values of an X-ray radiated section;

a decision unit for making a decision as to whether the computed CT values are included in the database; and

a display unit for displaying the first scan projection image, the second scan projection image, or a sectional image obtained from the CT values, together with a result of the decision.

4. A threat detection system according to claim 2, wherein the image pickup device comprises an X-ray tube and a line sensor disposed so as to be opposed to a gantry that can move in a circular arc form.

5. A threat detection system according to claim 2, wherein the first computation unit and the second computation unit are the same PC.

6. A method for detecting threats, the method comprising the steps of:

obtaining a first scan projection image from a first position by using an image pickup device;

moving the image pickup device from the first position to the second position;

obtaining a second scan projection image from the second position by using the image pickup device;

obtaining an X-ray absorption coefficient of an object subject to scan projection from the first scan projection image and the second scan projection image;

comparing the X-ray absorption coefficient of the object with an X-ray absorption coefficient database for threats;

obtaining a sectional image of the object;

comparing CT values obtained from the sectional image with a CT value database for threats; and

displaying a result of the comparison and one of the first scan projection image, the second projection image and the sectional image on the same picture.

7. A threat detection system comprising:

an image pickup device for acquiring scan projection data while moving on a circular arc from a first direction to a second direction with respect to an inspection subject;

a fixing unit for the inspection subject, the fixing unit comprising a first conveyor disposed on an inlet side of a movement axis of the image pickup device and a second conveyor disposed on an outlet side of the movement axis of the image pickup device;

a storage unit for retaining a CT value database of threats;

a computation unit for computing CT values of an X-ray radiated section;

a decision unit for making a decision as to whether the computed CT values are included in the database; and

a display unit for displaying a result of the decision,

wherein the first conveyor and the second conveyor are disposed in positions as not to intercept an X-ray path of the image pickup device.