Cargo inspection apparatus and process

• US 6,567,496 B1
• Filed: 10/11/2000
• Issued: 05/20/2003
• Est. Priority Date: 10/14/1999
• Status: Expired due to Term

• Current Assignee: Scantech Identification Beam Systems, LLC (ScanTech Holdings, LLC)
• Original Assignee: Biosterile Technology Incorporated
• Inventors: Sychev, Boris S.
• Primary Examiner(s): Kim, Robert H.
• Assistant Examiner(s): WANG, GEORGE Y
• Application Number:
  US09/686,048
• Time in Patent Office: 951 Days
• Field of Search: 378/57, 378/98.9, 378/53, 378/98.12, 378/90, 378/70, 378/98.11, 378/88, 378/89
• US Class Current: 378/57
• CPC Class Codes: G01N 23/04 and forming images of the material
• CPC Class Codes: G01N 23/10 the material being confined in a container, e.g. in a luggage X-ray scanners
• 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 5/224 Multiple energy techniques using one type of radiation, e.g. X-rays of different energies

Abstract

A cargo inspection apparatus and process includes scanning containers with x-rays along two different planes. Outputs from x-ray sensors along the two different planes are collected for use in establishing the presence of contraband within the container. Using the sensor output data, images of the container are provided and suspicious areas and background areas are identified on the images. By using representative suspicious area and background area geometry and compensating in the suspicious area for the effective estimated background thereat, the average atomic number and density of the suspicious contraband is established. The average atomic number and density is then compared with known atomic numbers and densities of contraband materials and an output indicative of whether the suspicious area falls within the parameters of actual contraband material is provided.

Claims

1. A process for detecting contraband within a container comprising the steps of:

scanning the container with x-rays along a first plane and obtaining a first sequence of one dimensional transmission intensity measurements from outputs of a plurality of x-ray sensors for a first x-ray intensity spectrum, and obtaining a second sequence for the first plane of one dimensional transmission intensity measurements from outputs of a plurality of x-ray sensors for a second x-ray intensity spectrum;

scanning the container with x-rays along a second plane and obtaining a first sequence of a one dimensional transmission intensity measurements from outputs of a plurality of x-ray sensors for a first x-ray intensity spectrum, and obtaining a second sequence for the second plane of one dimensional transmission intensity measurements from outputs of a plurality of x-ray sensors for a second x-ray intensity spectrum;

using said first plane first intensity spectrum sequence of one dimensional transmission intensity measurements and said first plane second intensity spectrum sequence of one dimensional transmission intensity measurements to calculate a sequence of first plane atomic number values and mass thickness values;

using said second plane first intensity spectrum sequence of one dimensional transmission intensity measurements and said second plane second intensity spectrum sequence of one dimensional transmission intensity measurements to calculate a sequence of second plane atomic number values and mass thickness values;

providing a first plane image by processing at least one of said first or second sequence of one dimensional transmission intensity measurements and providing a second plane image by processing at least one of said second plane first or second sequence of one dimensional transmission intensity measurements;

identifying a suspicious area in at least one of said first plane image or said second plane image;

using the atomic number values and mass thickness values calculated for said suspicious area to calculate an average atomic number value and an average density value for the suspicious area; and

,

comparing the average atomic number value and average density value for the suspicious area with known atomic number values and density values of actual contraband materials and providing an output indicative of whether the calculated average atomic number value and average density value for the suspicious area fall within those of an actual contraband material.

2. The process of claim 1 further including steps of:

combining said first plane atomic number values with said first plane image to provide a representative first plane atomic number display image thereof; and

,

combining said second plane atomic number values with said second plane image to provide a representative second plane atomic number display image thereof.

3. The process of claim 2 wherein, during the steps of combining and providing first and second plane atomic number display images, different atomic numbers are displayed in different colors.

4. The process of claim 3 wherein different colors are displayed on said atomic number display images for organic substances, explosives and drugs, light and heavy metals.

5. The process of claim 2 further including a step of identifying a suspicious area wherein an operator views and draws a frame around said suspicious area including a background area on said first plane atomic number display image, and the said operator also views and draws a corresponding frame around said suspicious area including background area on said second plane atomic number display image.

6. The process of claim 5 wherein during the step of identifying said suspicious and background areas the operator views said suspicious and background areas on both said first and second plane atomic number display images, and using a computer mouse clicks about said suspicious and background areas to automate definition thereof.

7. The process of claim 1 wherein during the step of identifying said suspicious area an operator views and draws a frame around said suspicious area including a background area on said first plane image, and also views and draws a frame around said suspicious area including a background area on said second plane image.

8. The process of claim 7 wherein during the step of identifying said suspicious area the operator views said suspicious and background areas of either said first plane image or said second plane image and using a computer mouse clicks about said suspicious and background areas to automate definition thereof.

9. The process of claim 7 wherein prior to the step of calculating the average atomic number value and average density value for the suspicious area, an average mass thickness for the suspicious area in said first plane image is calculated by subtracting a background area mass thickness value from the calculated mass thickness value for said suspicious area thereof, and an average mass thickness for the suspicious area in said second plane image is calculated by subtracting a background mass thickness value from the calculated mass thickness value for said suspicious area thereof.

10. The process of claim 1 wherein a first plurality of x-ray sensors are used during the steps of scanning two different x-ray energy levels to obtain the first and second sequences of one dimensional transmission intensity measurements along said first plane, and a second plurality of x-ray sensors are used during the steps of scanning two different x-ray energy levels to obtain the first and second sequence of one dimensional transmission intensity measurements along said second plane.

11. The process of claim 1 wherein every other x-ray sensor is provided with a filter and wherein said first sequence of one dimensional transmission intensity measurements are obtained from outputs of filtered sensors and said second sequence of one dimensional transmission intensity measurements are obtained from outputs of non-filtered x-ray sensors.

12. The process of claim 1 wherein said first and second sequence of one dimensional transmission intensity measurements of said first plane are combined to provide a first gray scale x-ray image for said first plane, and said first and second sequence of one dimensional transmission intensity measurements of said second plane are combined to provide a second gray scale x-ray image for said second plane.