Data collection, processing and storage systems for X-ray tomographic images

• US 8,958,526 B2
• Filed: 02/10/2012
• Issued: 02/17/2015
• Est. Priority Date: 12/16/2005
• Status: Active Grant

• Current Assignee: Rapiscan Systems Incorporated (OSI Systems Incorporated)
• Original Assignee: Rapiscan Systems Incorporated (OSI Systems Incorporated)
• Inventors: Morton, Edward James
• Primary Examiner(s): Artman, Thomas R
• Application Number:
  US13/370,941
• Publication Number:
  US 20120230463A1
• Time in Patent Office: 1,103 Days
• Field of Search: 378/57, 378/86, 378/87, 378/90, 378/122
• US Class Current: 378/57
• CPC Class Codes: G01N 2223/3304 helicoidal scan
• CPC Class Codes: G01N 2223/3307 source and detector fixed; object moves
• CPC Class Codes: G01N 2223/3308 object translates
• CPC Class Codes: G01N 2223/401 image processing
• CPC Class Codes: G01N 2223/419 computed tomograph
• CPC Class Codes: G01N 2223/421 digitised image, analysed in real time (recognition algorithms)
• CPC Class Codes: G01N 2223/5015 linear array
• CPC Class Codes: G01N 2223/639 material in a container
• CPC Class Codes: G01N 2223/643 object on conveyor
• CPC Class Codes: G01N 23/046 using tomography, e.g. computed tomography [CT]
• CPC Class Codes: G01N 23/10 the material being confined in a container, e.g. in a luggage X-ray scanners
• CPC Class Codes: G01N 23/20083 by using a combination of at least two measurements at least one being a transmission measurement and one a scatter measurement
• CPC Class Codes: G01T 1/246 utilizing latent read-out, e.g. charge stored and read-out later
• CPC Class Codes: G01T 1/247 Detector read-out circuitry for processing gain or off-set correction H04N
• CPC Class Codes: G01T 1/2985 In depth localisation, e.g. using positron emitters; Tomographic imaging (longitudinal and transverse section imaging; apparatus for radiation diagnosis sequentially in different planes, steroscopic radiation diagnosis); using external radiation sources A61B6/02
• 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 5/226 using tomography
• CPC Class Codes: G06T 7/12 Edge-based segmentation
• CPC Class Codes: G06T 7/143 involving probabilistic approaches, e.g. Markov random field [MRF] modelling
• CPC Class Codes: G06T 7/187 : involving region growing; involving region merging; involving connected component labelling

Abstract

The present specification discloses an X-ray scanning system for scanning an object. The processing system has processors adapted to receive X-ray tomographic image data and extract parameters from the data, where the parameters include constant grey level, texture or statistics. The processing system also includes processors for executing decision trees, where the processors receive the parameters and construct information using the parameters and processors for conducting a database search, where the database search maps the information to a threat level and allocates the object being scanned to a safety category.

Claims

1. A X-ray scanning system for scanning an object having a processing system, wherein said processing system comprises:

a multi-focus X-ray source arranged to generate X-rays from more than two X-ray source positions located around a scanning region, each of said X-ray source positions comprising grid wires, wherein said multi-focus X-ray source does not move during a scan;

a control unit to control an electrical potential applied to said grid wires of each of said X-ray source positions to cause an emission of X-rays from each of said X-ray source positions;

a first set of detectors arranged to detect X-rays transmitted through the scanning region;

a second set of detectors arranged to detect X-rays scattered within the scanning region;

processors adapted to receive X-ray tomographic image data, identify separate regions in the image, and extract a plurality of parameters from said data, wherein said parameters include at least one of constant grey level or texture and wherein identifying separate regions comprises calculating a mean intensity of a set of pixels within said image, determining a standard deviation of intensities of said set of pixels, determining an intensity of a pixel proximate to said set of pixels, and adding said pixel to the set of pixels to form a region if the intensity of said pixel is within said standard deviation;

processors for executing a plurality of decision trees, wherein said processors for executing a plurality of decision trees receive said parameters and construct information using said parameters; and

processors for conducting a database search, wherein said database search maps the information to a level of threat and allocates the object being scanned to a safety category.

2. The X-ray scanning system of claim 1 wherein said extractor processors comprise a first extractor processor configured to determine a first parameter and a second extractor processor configured to determine a second parameter, wherein the first parameter is different from the second parameter.

3. The X-ray scanning system of claim 2 wherein the first extractor processor operates in parallel with said second extractor processor.

4. The X-ray scanning system of claim 1 wherein the system further generates an automatic sorting control output based upon said safety category.

5. The X-ray scanning system of claim 1 wherein processors for extracting the plurality of parameters divide an image of the object being scanned into regions and measure a variance of pixel intensity within each of said regions.

6. The X-ray scanning system of claim 1 wherein processors for extracting the plurality of parameters divide an image of the object being scanned into regions and measure a skewedness of a distribution of pixel values within each of said regions.

7. The X-ray scanning system of claim 6 wherein a uniformity of material within each of said regions is determined based upon said measured skewedness.

8. The X-ray scanning system of claim 1 wherein said information comprises a ratio of a surface area of a region in an image of an object being scanned to a volume of said region.

9. The X-ray scanning system of claim 1 wherein said information comprises a measure of similarity of a shape of a region in an image of an object being scanned to a shape stored in a memory.

10. The X-ray scanning system of claim 1 wherein the processing system determines a measure of a level of scattering from different positions within the scanning region from the detected scattered X-rays.

11. The X-ray scanning system of claim 1 wherein the processing system determines, from a position of a detector in said second set of detectors and a direction from which the X-ray was directed at the scanning region, the position at which the X-ray was scattered.

12. The X-ray scanning system of claim 11 wherein the scattering is incoherent scattering.

13. The X-ray scanning system of claim 1 wherein the processing system determines from the X-ray tomographic image data an indication of a position at which the scattered X-rays have been scattered.

14. The X-ray scanning system of claim 1 wherein the processing system defines a plurality of pixels within X-ray tomographic image data, identifies at least one of the pixels as being associated with the object, and associates parts of scattering data with said associated pixels.

15. The X-ray scanning system of claim 1 wherein the two sets of detectors are on opposite sides of the source.

16. The X-ray scanning system of claim 15 wherein the first set of detectors are arranged in an arc defining an axis of the system.

17. The X-ray scanning system of claim 16 wherein the second set of detectors are arranged in a plurality of arcs around the system axis, the arcs being spaced along the axis.

18. The X-ray scanning system of claim 1 wherein the processing system determines which area within the scanning region is associated with CT image data or scattering data at least partly based on from which detector said CT image data or scattering data is received.

19. The X-ray scanning system of claim 1 wherein the processing system combines CT image data from tomographic scans to produce a three-dimensional image of the object.