X-Ray Tomography Inspection Systems

• US 20080304622A1
• Filed: 12/15/2006
• Published: 12/11/2008
• Est. Priority Date: 12/16/2005
• Status: Active Grant

• Current Assignee: Rapiscan Systems Incorporated (OSI Systems Incorporated)
• Original Assignee: Edward James Morton
• Inventors: Morton, Edward James
• Granted Patent: US 7,876,879 B2
• Time in Patent Office: Days
• US Class Current: 378/51
• 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

An X-ray imaging inspection system for inspecting items comprises an X-ray source (10) extending around an imaging volume (16), and defining a plurality of source points (14) from which X-rays can be directed through the imaging volume. An X-ray detector array (12) also extends around the imaging volume (16) and is arranged to detect X-rays from the source points which have passed through the imaging volume, and to produce output signals dependent on the detected X-rays. A conveyor (20) is arranged to convey the items through the imaging volume (16).

Claims

1. A networked inspection system comprising:

an X-ray scanning system, a workstation and a connection means arranged to connect the scanning system to the workstation, the scanning system comprising;

an X-ray source extending around a scanning volume, and defining a plurality of source points from which X-rays can be directed through the scanning volume, an X-ray detector array also extending around the scanning volume and arranged to detect X-rays from the source points which have passed through the scanning volume and produce output signals dependent on the detected X-rays, and a conveyor arranged to convey the items through the scanning volume.

2. A system according to claim 1 wherein the X-ray source comprises an electron source arranged to generate an electron beam from each of a plurality of electron source positions, the electron beams each being arranged to generate X-rays from a respective X-ray source position on an anode.

3. A system according to claim 2 wherein the electron source positions are arranged around the scanning volume.

4. A system according to claim 1 further comprising processing means arranged to produce, from the detector output signals, attenuation data indicative of the level of X-ray attenuation in a plurality of parts of the scanning volume.

5. A system according to claim 4 wherein the scanner is arranged to scan a plurality of regions of each item as it moves along the conveyor, and the attenuation data is indicative of the level of attenuation in parts of each of those regions.

6. A system according to claim 4 wherein the attenuation data is in the form of image data suitable for producing an image of a scanned item.

7. A system according to claim 6 wherein the image data is suitable for producing a three dimensional tomographic image.

8. A system according to claim 6 further comprising display means arranged to display an image derived from the image data.

9. A system according to claim 4 including analyzing means arranged to analyze the attenuation data and produce an output signal that is dependent on a parameter of the attenuation data.

10. A system according to claim 9 wherein the analyzing means is arranged to allocate each of the items to one of a plurality of categories.

11. A system according to claim 10 further comprising sorting means arranged to sort the items at least partly depending on the output signal from the analyzing means.

12. A system according to claim 9 wherein the analyzing means is arranged to receive a user input signal generated from a user input, and to allocate the items at least partly depending on the user input signal.

13. A system according to claim 1 wherein the scanning system is arranged to produce a set of scanning data, and the system comprises a plurality of workstations, and the connection means is arranged to connect the scanning system to each of the workstations, and the system further comprises switching means arranged to select which of the workstations receives the data from the scanning system.

14. A system according to claim 1 comprising a plurality of scanning systems each arranged to produce sets of scanning data, the connection means being arranged to connect each of the scanning systems to the workstation, and the system further comprising switching means arranged to select which of the sets of scanning data is sent to the workstation.

15. A system according to claim 1 comprising a plurality of scanning systems each arranged to produce sets of scanning data, and a plurality of workstations, the connection means being arranged to connect each of the scanning systems to each of the workstations, and the system further comprising switching means arranged to select which of the workstations receives each set data from each of the scanning systems.

16. A system according to claim 15 wherein each scanning system is arranged to produce an image data set for each of a plurality of items, and an allocation data set relating to a category to which the item has been allocated, and the switching means is arranged to direct the image data for each item to the same workstation as the allocation data for the same item.

17. A system according to claim 1, wherein the X-ray detector array is offset in an axial direction from the X-ray source.

18. A sorting system for sorting items, the system comprising a tomographic scanner arranged to scan a plurality of scanning regions of each item thereby to produce a scanner output, analyzing means arranged to analyze the scanner output and allocate each item to one of a plurality of categories at least partly on the basis of the scanner output, and sorting means arranged to sort items at least partly on the basis of the categories to which they have been allocated.

19. A sorting system according to claim 18 wherein the sorting means is arranged to receive the items at an input position and transfer each of them to one of a plurality of output positions each of which is associated with a respective one of the categories.

20. A sorting system according to claim 19 further comprising an input conveyor arranged to convey the items to the input position and a further scanner, wherein each of the scanners has a scanning conveyor arranged to convey items through the scanner, and sorting means arranged to sort items from the input conveyor onto each of the scanning conveyors.

21. A sorting system according to claim 20 wherein the input conveyor is arranged to travel faster than the scanning conveyors.

22. A sorting system according to claim 19 further comprising an output conveyor arranged to convey the items from an output position of the scanner, and a further scanner, wherein each of the scanners has a scanning conveyor arranged to convey items through the scanner, and sorting means arranged to sort items from each of the scanning conveyors onto the input conveyor.

23. A sorting system according to claim 22 wherein the output conveyor is arranged to travel faster than the scanning conveyors.

24. A sorting system according to claim 18 further comprising imaging means arranged to produce an image from the scanner output and a user input arranged to enable a user to generate a user input signal, wherein the analyzing means is arranged to allocate the items at least partly depending on the user input signal.

25. A system according to claim 24 wherein the analyzing means is arranged to generate a provisional allocation of each item on the basis of the scanner output, and a final allocation of each item on the basis of the scanner output and the user input.

26. A system according to claim 25 further comprising conveying means arranged to convey each item from the scanner to the sorting means and to provide a delay between the scanning and sorting of each item during which the user can generate the user input signal.

27. A sorting system according to claim 18 wherein each of the categories has a conveyor associated with it, and the system further comprises a backup scanner arranged to scan items on one of the conveyors, and a further sorting means arranged to transfer items from said one conveyor to the other conveyor if the back-up scanner determines that they should be allocated to the appropriate category.

28. A sorting system according to claim 18 wherein the analyzing means includes a plurality of scanners, the system further comprising a conveyor loop arranged to receive items from a plurality if input conveyors, and a plurality of sorting devices arranged to take items from the conveyor loop and transfer them to a respective one of the scanners.

29. (canceled)

30. (canceled)

31. (canceled)

32. (canceled)

33. (canceled)

34. (canceled)

35. (canceled)

36. (canceled)

37. (canceled)

38. (canceled)

39. (canceled)

40. (canceled)

41. (canceled)

42. (canceled)

43. (canceled)

44. (canceled)

45. An X-ray scanning system comprising a scanner arranged to scan an object to generate scanning data defining a tomographic X-ray image of the object, and processing means arranged to analyze the scanning data to extract at least one parameter of the image data and to allocate the object to one of a plurality of categories on the basis of the at least one parameter.

46. A system according to claim 45 further comprising sorting means arranged to receive objects at an input, and transfer them to one of a plurality of outputs depending on the category to which they have been allocated.

47. A system according to claim 45 wherein the scanning data is arranged to include scattering data.

48. A system according to claim 45 wherein the scanning data is arranged to define a projection image.

49. A system according to claim 45 wherein the processing means is arranged to identify regions of the image and to identify the parameter by analyzing one of the regions.

50. A system according to claim 49 wherein the processing means is arranged to identify whether a pixel of the image belongs to a region by comparing a value associated with the pixel with a corresponding value associated with the region, and if a predetermined relationship is found between the two values, to include the pixel in the region.

57. A system according to claim 45 wherein the processing means is arranged to extract a plurality of parameters from the scanning data, and includes a plurality of parameter extraction modules arranged to operate in parallel to extract respective parameters from the scanning data.

58. A system according to claim 45 further comprising a decision tree arranged to derive information from the parameters.

51. A method of identifying a region of a digital image comprising the steps of:

a. defining an initial area of the region;

b. identifying a pixel outside the initial area;

c. determining a value associated with the pixel;

d. determining a corresponding value of the initial area; and

e. comparing the values and, if a predetermined relationship is found between the two values, including the pixel in the region.

52. A method according to claim 51 wherein the pixel is adjacent to the initial area.

53. A method according to claim 51 further comprising repeating steps b) to e) until all pixels adjacent to the region have been checked and none of them added to the region.

54. A method according to claim 51 wherein the value is an intensity value.

55. A method according to claim 54 wherein the predetermined relationship comprises the intensity of the pixel being within a predetermined range of an average intensity of the initial region.

56. A system for identifying a region of a digital image, the system comprising processing means arranged to carry out the steps of claim 51.

59. An X-ray scanning system comprising a scanner and processing means wherein the scanner comprises an X-ray source arranged to produce X-rays at two different energies and detectors arranged to detect the X-rays at each of the frequencies to produce two respective scanner outputs, the scanner is arranged to scan a plurality of regions of the object, and the processing means is arranged to process signals from the detectors so as to generate a plurality of tomographic image data sets and to combine the data sets to generate a three dimensional image of the object, wherein the processing means is arranged to combine the two scanner outputs to produce the image data sets.

60. An X-ray scanning and sorting system comprising a scanner and processing means, wherein the scanner comprises an X-ray source arranged to produce X-rays from a plurality of source points, and first and second arrays of detectors arranged to detect the X-rays, and the processing means is arranged to process signals from the first array of detectors to produce tomographic image data of a scanned object, and to process signals from the second array of detectors so as to produce projection image data of the scanned object, and the processing means is arranged to process the tomographic image data and the projection image data of the scanned object and to allocate the scanned object to one of a plurality of categories.

61. A system according to claim 60 wherein each of the second array of detectors is connected to a data collection means that is arranged to collect data from each of the sensors in the second array simultaneously to produce the projection image data.

62. A system according to claim 61 wherein the data collection means is arranged to collect data from the sensors in the second array when each of two source points is active, so as to produce two sets of projection image data.

63. A system according to claim 62 wherein the processing means is arranged to combine the two sets of projection data to produce a 3-dimensional image.

64. (canceled)

65. (canceled)

66. (canceled)

67. (canceled)