Electronic planar laminography system and method

• US 6,324,249 B1
• Filed: 03/21/2001
• Issued: 11/27/2001
• Est. Priority Date: 03/21/2001
• Status: Expired due to Fees

• Current Assignee: Agilent Technologies, Inc.
• Original Assignee: Agilent Technologies, Inc.
• Inventors: Fazzio, R. Shane
• Primary Examiner(s): Porta, David P.
• Assistant Examiner(s): Yun, Jurie
• Application Number:
  US09/813,778
• Time in Patent Office: 251 Days
• Field of Search: 378/21, 378/22, 378/24, 378/25, 378/58, 378/98.8
• US Class Current: 378/22
• CPC Class Codes: G01N 23/044 using laminography or tomosynthesis

Abstract

An improved linear scan geometry laminography system that allows for generation of high speed and high resolution X-ray laminographs using an electronic detector operating in a time-domain integration mode coupled with a moving source of X-rays. In one embodiment, the improved scanning laminography system does not require any mechanical motion of the object being inspected, the X-ray source or detectors. Higher speed is achieved over conventional laminography systems due to the electronic nature of the scan. The same architecture also allows for both two-dimensional radiography and digital reconstruction techniques. Usage of the technique provides for higher throughput, higher resolution, and simpler designs than do currently available systems. An analysis of different system design parameters for the basic X-ray imaging architecture utilizing time-domain integration to generate cross-sectional images is included to facilitate specific design configurations. The relationships between resolution, speed, and cost are considered.

Claims

1. An apparatus for producing a laminographic cross sectional image of a cutting plane of an object comprising:

a scanning X-ray source;

an X-ray detector positioned to receive X-rays from said scanning X-ray source which have passed through the object, said X-ray detector comprising;

a plurality of X-ray sensitive elements forming an array wherein each X-ray sensitive element is adapted to sense and generate an X-ray intensity signal value corresponding to the intensity of X-rays received thereon such that said X-ray intensity signal value on any specific X-ray sensitive element is indicative of the total intensity of X-rays received by that specific X-ray sensitive element; and

connections between said X-ray sensitive elements adapted to allow said X-ray intensity signal values to be shifted from X-ray sensitive element to X-ray sensitive element of said array in response to shift signals corresponding to a first timing pattern such that said X-ray intensity signal values of individual X-ray sensitive elements represent an integration of X-ray intensities received at a plurality of X-ray sensitive element locations as the X-ray intensity signal values shift from X-ray sensitive element to X-ray sensitive element in response to said first timing pattern; and

a control system which coordinates positioning of said scanning X-ray source with the shifting of said X-ray sensitive element X-ray intensity signal values in accordance with said first timing pattern thereby accumulating data which is representative of a laminographic cross sectional image of a first cutting plane of the object.

2. An apparatus as defined in claim 1 wherein:

said X-ray detector further responds to a second timing pattern such that said X-ray intensity signal values of individual X-ray sensitive elements represent an integration of X-ray intensities received at said plurality of X-ray sensitive element locations as said X-ray intensity signal values shift from X-ray sensitive element to X-ray sensitive element in response to said second timing pattern; and

said control system coordinates positioning of said scanning X-ray source with the shifting of said X-ray sensitive element X-ray intensity signal values in accordance with said second timing pattern thereby accumulating data which is representative of a laminographic cross sectional image of a second cutting plane of the object.

3. An apparatus as defined in claim 2 wherein:

said first timing pattern comprises a first X-ray source scan rate and a first X-ray detector scan rate; and

said second timing pattern comprises a second X-ray source scan rate and a second X-ray detector scan rate.

4. An apparatus as defined in claim 3 wherein said first X-ray source scan rate and said second X-ray source scan rate are substantially equal.

5. An apparatus as defined in claim 3 wherein said first X-ray detector scan rate and said second X-ray detector scan rate are substantially equal.

6. An apparatus as defined in claim 1 wherein:

said X-ray detector further responds to a radiographic timing pattern which causes said X-ray intensity signal values of individual X-ray sensitive elements to remain stationary with respect to said array; and

said control system positions said scanning X-ray source at a stationary location such that said X-ray detector accumulates data which is representative of a conventional X-ray shadowgraph image of the object in accordance with said radiographic timing pattern.

7. An apparatus as defined in claim 1 wherein:

said X-ray detector further responds to a tomographic timing pattern such that said X-ray intensity signal values of individual X-ray sensitive elements are collected in accordance with a tomographic pattern; and

said control system coordinates positioning of said scanning X-ray source with the shifting of said X-ray sensitive element X-ray intensity signal values in accordance with said tomographic timing pattern thereby accumulating data from which a digital reconstruction of a tomographic cross sectional image of the object may be reconstructed.

8. An apparatus as defined in claim 1 wherein:

said X-ray detector further responds to a tomosynthesis timing pattern such that said X-ray intensity signal values of individual X-ray sensitive elements are collected in accordance with a tomosynthesis pattern; and

said control system coordinates positioning of said scanning X-ray source with the shifting of said X-ray sensitive element X-ray intensity signal values in accordance with said tomosynthesis timing pattern thereby accumulating data from which a digital reconstruction of a tomosynthesis cross sectional image of the object may be reconstructed.

9. An apparatus as defined in claim 1 wherein said scanning X-ray source follows a linear scan direction.

10. An apparatus as defined in claim 1 wherein said scanning X-ray source follows a circular scan direction.

11. An apparatus as defined in claim 1 wherein said scanning X-ray source follows a scan direction determined by a grid.

12. An apparatus as defined in claim 1 wherein said X-ray detector further comprises an X-ray scintillator which converts X-rays to light and a charged coupled device (CCD) which receives and detects said light produced by said X-ray scintillator.

13. An apparatus as defined in claim 1 wherein said X-ray detector further comprises a solid state X-ray detector array which receives X-rays and produces electrical signals in response to receiving X-rays.

14. An apparatus as defined in claim 1 wherein said X-ray detector further comprises a gas detector which receives X-rays and produces electrical signals in response to receiving X-rays.

15. An apparatus for producing a laminographic cross sectional image of a cutting plane of a stationary object comprising:

a scanning X-ray source;

an X-ray detector positioned to receive X-rays from said scanning X-ray source which have passed through the stationary object, said X-ray detector comprising;

a plurality of X-ray sensitive regions forming an array wherein each X-ray sensitive region is adapted to sense X-rays and generate X-ray intensity signal values corresponding to the intensity of X-rays received thereon; and

connections between said X-ray sensitive regions adapted to allow said X-ray intensity signal values to be shifted from X-ray sensitive region to X-ray sensitive region of said array in response to shift signals corresponding to a first timing pattern such that said X-ray intensity signal values of individual X-ray sensitive regions represent an integration of X-ray intensities received at a plurality of X-ray sensitive region locations as said X-ray intensity signal values shift from X-ray sensitive region to X-ray sensitive region in response to said first timing pattern; and

a control system which coordinates positioning of said scanning X-ray source with said plurality of said X-ray sensitive regions of said X-ray detector such that;

first X-ray image data of the stationary object is collected by a first X-ray sensitive region of said X-ray detector when said X-ray source is located at a first position wherein a first angular relationship is formed between said X-ray source at said first position and said first X-ray sensitive region of said X-ray detector during collection of said first X-ray image data;

second X-ray image data of the stationary object is formed on a second X-ray sensitive region of said X-ray detector when said X-ray source is located at a second position wherein a second angular relationship is formed between said X-ray source at said second position and said second X-ray sensitive region of said X-ray detector during collection of said second X-ray image data; and

said first X-ray image data of the stationary object at said first angular configuration and said second X-ray image data of the stationary object at said second angular configuration are combined thereby creating data representative of a laminographic cross sectional image of a first cutting plane of the stationary object.

16. An apparatus as defined in claim 15 wherein:

said X-ray detector further responds to a second timing pattern such that said X-ray intensity signal values of individual X-ray sensitive regions represent an integration of X-ray intensities received at said plurality of X-ray sensitive region locations as said X-ray intensity signal values shift from X-ray sensitive region to X-ray sensitive region in response to said second timing pattern; and

said control system coordinates positioning of said scanning X-ray source with said plurality of said X-ray sensitive regions of said X-ray detector in accordance with said second timing pattern such that;

third X-ray image data of the stationary object is formed on said second X-ray sensitive region of said X-ray detector when said X-ray source is located at a third position wherein a third angular relationship is formed between said X-ray source at said third position and said second X-ray sensitive region of said X-ray detector during collection of said third X-ray image data; and

said first X-ray image data of the stationary object at said first angular configuration and said third X-ray image data of the stationary object at said third angular configuration are combined thereby creating data which is representative of a laminographic cross sectional image of a second cutting plane of the stationary object.

17. An apparatus as defined in claim 16 wherein:

said first timing pattern comprises a first X-ray source scan rate and a first X-ray detector scan rate; and

said second timing pattern comprises a second X-ray source scan rate and a second X-ray detector scan rate.

18. An apparatus as defined in claim 15 wherein:

said X-ray detector further responds to a tomographic timing pattern such that said X-ray intensity signal values of individual X-ray sensitive regions are collected in accordance with a tomographic pattern; and

said control system coordinates positioning of said scanning X-ray source with the shifting of said X-ray sensitive region X-ray intensity signal values in accordance with said tomographic pattern thereby accumulating data from which a digital reconstruction of a tomographic cross sectional image of the object may be reconstructed.

19. An apparatus as defined in claim 15 wherein:

said scanning X-ray source follows a linear scan direction;

said X-ray detector further comprises a detector array wherein individual X-ray sensitive elements comprising said detector array are arranged in a plurality of linear rows and linear columns, said linear rows being substantially perpendicular to said X-ray source linear scan direction and said linear columns being substantially parallel to said X-ray source linear scan direction; and

regions of the stationary object being imaged are linear regions which are substantially perpendicular to said X-ray source linear scan direction and substantially parallel to said linear rows of said detector array.

20. An apparatus as defined in claim 19 wherein said X-ray detector array further comprises an X-ray scintillator which converts X-rays to light and a charged coupled device (CCD) which receives and detects said light produced by said X-ray scintillator.

21. An apparatus for producing a laminographic cross sectional image of a cutting plane of a stationary object comprising:

a scanning X-ray source which scans along a first linear path;

an X-ray detector array positioned to receive X-rays from said scanning X-ray source which have passed through the object, said X-ray detector array comprising;

a plurality of adjacent X-ray sensitive rows which are substantially perpendicular to said X-ray source first linear path wherein each X-ray sensitive row is adapted to sense X-rays and generate X-ray intensity signal values corresponding to the intensity of X-rays received thereon; and

connections between said adjacent X-ray sensitive rows adapted to allow said X-ray intensity signal values to be shifted from X-ray sensitive row to X-ray sensitive row of said X-ray detector array in response to shift signals corresponding to a first timing pattern such that said X-ray intensity signal values of individual X-ray sensitive rows represent multiple angle integrations of X-ray intensities received at a plurality of X-ray sensitive row locations at a plurality of angular orientations of said scanning X-ray source locations and said X-ray detector X-ray sensitive row locations as said X-ray intensity signal values shift from X-ray sensitive row to X-ray sensitive row in response to said first timing pattern; and

a control system which coordinates positioning of said scanning X-ray source with the shifting of said X-ray intensity signal values of said X-ray detector in accordance with said first timing pattern thereby creating data representative of a laminographic cross sectional image of a first cutting plane of the stationary object.

22. An apparatus as defined in claim 21 wherein:

said X-ray detector further responds to a second timing pattern such that said X-ray intensity signal values of individual X-ray sensitive rows represent an integration of X-ray intensities received at said plurality of X-ray sensitive row locations as said X-ray intensity signal values shift from X-ray sensitive row to X-ray sensitive row in response to said second timing pattern; and

said control system coordinates positioning of said scanning X-ray source with the shifting of said X-ray intensity signal values in accordance with said second timing pattern thereby accumulating data which is representative of a laminographic cross sectional image of a second cutting plane of the object.

23. An apparatus as defined in claim 22 wherein:

said first timing pattern comprises a first X-ray source scan rate and a first X-ray detector scan rate; and

said second timing pattern comprises a second X-ray source scan rate and a second X-ray detector scan rate.

24. An apparatus as defined in claim 21 wherein:

said X-ray detector further responds to a tomographic timing pattern such that said X-ray intensity signal values are collected in accordance with a tomographic pattern; and

said control system coordinates positioning of said scanning X-ray source with the shifting of said X-ray intensity signal values in accordance with said tomographic pattern thereby accumulating data from which a digital reconstruction of a tomographic cross sectional image of the object may be reconstructed.

25. An apparatus as defined in claim 21 wherein said X-ray detector array further comprises an X-ray scintillator which converts X-rays to light and a charged coupled device (CCD) which receives and detects said light produced by said X-ray scintillator.

26. An apparatus for producing a laminographic cross sectional image of a first cutting plane of an object comprising:

a scanning X-ray source;

a scanning X-ray detector array positioned to receive X-rays from said scanning X-ray source which have passed through the object, said scanning X-ray detector comprising;

a plurality of X-ray sensitive elements adapted to sense and generate X-ray intensity signal values corresponding to the intensity of X-rays received thereon, said X-ray intensity signal values thereby representing an X-ray image of a portion of the object; and

connections between said X-ray sensitive elements adapted to allow said X-ray intensity signal values representing X-ray images to be shifted from X-ray sensitive element to X-ray sensitive element of said scanning X-ray detector array in response to shift signals corresponding to a first timing pattern such that said X-ray intensity signal values of individual X-ray sensitive elements correspond to an integration of X-ray intensities received at a plurality of X-ray sensitive element locations and a plurality of angular orientations of said X-ray source and said scanning X-ray detector X-ray sensitive element locations as said X-ray intensity signal values representing X-ray images shift from X-ray sensitive element to X-ray sensitive element in response to said first timing pattern; and

a control system which coordinates positioning of said scanning X-ray source with the shifting of said X-ray sensitive element X-ray intensity signal values in accordance with said first timing pattern such that multiple angular image projections of the first cutting plane of the object are accumulated by said scanning X-ray detector array wherein any point in the first cutting plane of the object is projected to approximately the same shifted point of the scanning X-ray detector array X-ray sensitive elements and any point outside the first cutting plane is projected to a plurality of shifted points of the scanning X-ray detector array X-ray sensitive elements during a cycle of the first timing pattern thereby accumulating data which is representative of a laminographic cross sectional image of the first cutting plane of the object.

27. An apparatus as defined in claim 26 wherein:

said scanning X-ray detector array further responds to a second timing pattern such that said X-ray intensity signal values of individual X-ray sensitive elements represent an integration of X-ray intensities received at said plurality of X-ray sensitive element locations and said plurality of angular orientations of said X-ray source and said scanning X-ray detector array X-ray sensitive element locations as said X-ray intensity signal values representing X-ray images shift from X-ray sensitive element to X-ray sensitive element in response to said second timing pattern; and

said control system coordinates positioning of said scanning X-ray source with the shifting of said X-ray sensitive element X-ray intensity signal values in accordance with said second timing pattern such that multiple angular image projections of a second cutting plane of the object are accumulated by said scanning X-ray detector array wherein any point in the second cutting plane of the object is projected to approximately the same shifted point of the scanning X-ray detector array X-ray sensitive elements and any point outside the second cutting plane is projected to a plurality of shifted points of the scanning X-ray detector array X-ray sensitive elements during a cycle of the second timing pattern thereby accumulating data which is representative of a laminographic cross sectional image of a second cutting plane of the object.

28. An apparatus as defined in claim 27 wherein:

said first timing pattern comprises a first X-ray source scan rate and a first X-ray detector scan rate; and

said second timing pattern comprises a second X-ray source scan rate and a second X-ray detector scan rate.

29. An apparatus as defined in claim 26 wherein:

said scanning X-ray detector array further responds to a tomographic timing pattern such that said X-ray intensity signal values of individual X-ray sensitive elements are collected in accordance with a tomographic pattern; and

said control system coordinates positioning of said scanning X-ray source with the shifting of said X-ray sensitive element X-ray intensity signal values in accordance with said tomographic pattern thereby accumulating data from which a digital reconstruction of a tomographic cross sectional image of the object may be reconstructed.

30. An apparatus as defined in claim 26 wherein said scanning X-ray source follows a linear scan direction.

31. An apparatus as defined in claim 26 wherein said scanning X-ray detector array further comprises an X-ray scintillator which converts X-rays to light and a charged coupled device (CCD) which receives and detects said light produced by said X-ray scintillator.

32. An apparatus for producing a laminographic cross sectional image of a cutting plane of an object comprising:

a stationary X-ray source;

a moving support for the object;

an X-ray detector positioned to receive X-rays from said stationary X-ray source which have passed through the object, said X-ray detector comprising;

a plurality of X-ray sensitive elements forming an array wherein each X-ray sensitive element is adapted to sense and generate an X-ray intensity signal value corresponding to the intensity of X-rays received thereon such that said X-ray intensity signal value on any specific X-ray sensitive element is indicative of the total intensity of X-rays received by that specific X-ray sensitive element; and

connections between said X-ray sensitive elements adapted to allow said X-ray intensity signal values to be shifted from X-ray sensitive element to X-ray sensitive element of said array in response to shift signals corresponding to a first timing pattern such that said X-ray intensity signal values of individual X-ray sensitive elements represent an integration of X-ray intensities received at a plurality of X-ray sensitive element locations as the X-ray intensity signal values shift from X-ray sensitive element to X-ray sensitive element in response to said first timing pattern; and

a control system which coordinates positioning of said moving support with the shifting of said X-ray sensitive element X-ray intensity signal values in accordance with said first timing pattern thereby accumulating data which is representative of a laminographic cross sectional image of a first cutting plane of the object.

33. An apparatus as defined in claim 32 wherein:

said X-ray detector further responds to a second timing pattern such that said X-ray intensity signal values of individual X-ray sensitive elements represent an integration of X-ray intensities received at said plurality of X-ray sensitive element locations as said X-ray intensity signal values shift from X-ray sensitive element to X-ray sensitive element in response to said second timing pattern; and

said control system coordinates positioning of said moving support with the shifting of said X-ray sensitive element X-ray intensity signal values in accordance with said second timing pattern thereby accumulating data which is representative of a laminographic cross sectional image of a second cutting plane of the object.

34. An apparatus as defined in claim 33 wherein:

said first timing pattern comprises a first moving support scan rate and a first X-ray detector scan rate; and

said second timing pattern comprises a second moving support scan rate and a second X-ray detector scan rate.

35. An apparatus as defined in claim 32 wherein:

said X-ray detector further responds to a tomographic timing pattern such that said X-ray intensity signal values of individual X-ray sensitive elements are collected in accordance with a tomographic pattern; and

said control system coordinates positioning of said moving support with the shifting of said X-ray sensitive element X-ray intensity signal values in accordance with said tomographic timing pattern thereby accumulating data from which a digital reconstruction of a tomographic cross sectional image of the object may be reconstructed.

36. An apparatus as defined in claim 32 wherein said moving support follows a linear scan direction.

37. An apparatus as defined in claim 32 wherein said X-ray detector further comprises an X-ray scintillator which converts X-rays to light and a charged coupled device (CCD) which receives and detects said light produced by said X-ray scintillator.

38. A method for producing a laminographic cross sectional image of a cutting plane of an object comprising the steps of:

scanning the object with a scanning X-ray source;

detecting X-rays from said scanning X-ray source which have passed through the object with an X-ray detector, said X-ray detector comprising;

a plurality of X-ray sensitive elements forming an array wherein each X-ray sensitive element is adapted to sense and generate an X-ray intensity signal value corresponding to the intensity of X-rays received thereon such that said X-ray intensity signal value on any specific X-ray sensitive element is indicative of the total intensity of X-rays received by that specific X-ray sensitive element; and

connections between said X-ray sensitive elements adapted to allow said X-ray intensity signal values to be shifted from X-ray sensitive element to X-ray sensitive element of said array in response to shift signals corresponding to a first timing pattern such that said X-ray intensity signal values of individual X-ray sensitive elements represent an integration of X-ray intensities received at a plurality of X-ray sensitive element locations as the X-ray intensity signal values shift from X-ray sensitive element to X-ray sensitive element in response to said first timing pattern; and

coordinating the position of said scanning X-ray source with the shifting of said X-ray sensitive element X-ray intensity signal values with a control system in accordance with said first timing pattern thereby accumulating data which is representative of a laminographic cross sectional image of a first cutting plane of the object.

39. A method as defined in claim 38 wherein:

said X-ray detector further responds to a second timing pattern such that said X-ray intensity signal values of individual X-ray sensitive elements represent an integration of X-ray intensities received at said plurality of X-ray sensitive element locations as said X-ray intensity signal values shift from X-ray sensitive element to X-ray sensitive element in response to said second timing pattern; and

said control system coordinates positioning of said scanning X-ray source with the shifting of said X-ray sensitive element X-ray intensity signal values in accordance with said second timing pattern thereby accumulating data which is representative of a laminographic cross sectional image of a second cutting plane of the object.

40. A method as defined in claim 39 wherein:

said first timing pattern comprises a first X-ray source scan rate and a first X-ray detector scan rate; and

said second timing pattern comprises a second X-ray source scan rate and a second X-ray detector scan rate.

41. A method as defined in claim 38 wherein:

said X-ray detector further responds to a tomographic timing pattern such that said X-ray intensity signal values of individual X-ray sensitive elements are collected in accordance with a tomographic pattern; and

said control system coordinates positioning of said scanning X-ray source with the shifting of said X-ray sensitive element X-ray intensity signal values in accordance with said tomographic timing pattern thereby accumulating data from which a digital reconstruction of a tomographic cross sectional image of the object may be reconstructed.

42. A method as defined in claim 38 wherein said scanning X-ray source follows a linear scan direction.

43. A method as defined in claim 38 wherein said X-ray detector further comprises an X-ray scintillator which converts X-rays to light and a charged coupled device (CCD) which receives and detects said light produced by said X-ray scintillator.

44. A method for producing a laminographic cross sectional image of a cutting plane of an object comprising:

providing a stationary X-ray source;

providing a moving support for the object;

positioning an X-ray detector to receive X-rays from said stationary X-ray source which have passed through the object, said X-ray detector comprising;

a plurality of X-ray sensitive elements forming an array wherein each X-ray sensitive element is adapted to sense and generate an X-ray intensity signal value corresponding to the intensity of X-rays received thereon such that said X-ray intensity signal value on any specific X-ray sensitive element is indicative of the total intensity of X-rays received by that specific X-ray sensitive element; and

connections between said X-ray sensitive elements adapted to allow said X-ray intensity signal values to be shifted from X-ray sensitive element to X-ray sensitive element of said array in response to shift signals corresponding to a first timing pattern such that said X-ray intensity signal values of individual X-ray sensitive elements represent an integration of X-ray intensities received at a plurality of X-ray sensitive element locations as the X-ray intensity signal values shift from X-ray sensitive element to X-ray sensitive element in response to said first timing pattern; and

providing a control system which coordinates positioning of said moving support with the shifting of said X-ray sensitive element X-ray intensity signal values in accordance with said first timing pattern thereby accumulating data which is representative of a laminographic cross sectional image of a first cutting plane of the object.

45. A method as defined in claim 44 wherein:

said X-ray detector further responds to a second timing pattern such that said X-ray intensity signal values of individual X-ray sensitive elements represent an integration of X-ray intensities received at said plurality of X-ray sensitive element locations as said X-ray intensity signal values shift from X-ray sensitive element to X-ray sensitive element in response to said second timing pattern; and

said control system coordinates positioning of said moving support with the shifting of said X-ray sensitive element X-ray intensity signal values in accordance with said second timing pattern thereby accumulating data which is representative of a laminographic cross sectional image of a second cutting plane of the object.

46. A method as defined in claim 45 wherein:

said first timing pattern comprises a first moving support scan rate and a first X-ray detector scan rate; and

said second timing pattern comprises a second moving support scan rate and a second X-ray detector scan rate.

47. A method as defined in claim 44 wherein:

said X-ray detector further responds to a tomographic timing pattern such that said X-ray intensity signal values of individual X-ray sensitive elements are collected in accordance with a tomographic pattern; and

said control system coordinates positioning of said moving support with the shifting of said X-ray sensitive element X-ray intensity signal values in accordance with said tomographic timing pattern thereby accumulating data from which a digital reconstruction of a tomographic cross sectional image of the object may be reconstructed.

48. A method as defined in claim 44 wherein said moving support follows a linear scan direction.

49. A method as defined in claim 44 wherein said X-ray detector further comprises an X-ray scintillator which converts X-rays to light and a charged coupled device (CCD) which receives and detects said light produced by said X-ray scintillator.