Tomography of curved surfaces

• US 6,850,589 B2
• Filed: 03/27/2002
• Issued: 02/01/2005
• Est. Priority Date: 03/27/2002
• Status: Expired due to Fees

• Current Assignee: Agilent Technologies, Inc., Nidec Jue-Choung Electronics Company Limited
• Original Assignee: Agilent Technologies, Inc.
• Inventors: Reynolds, David C., Heumann, John M.
• Primary Examiner(s): Glick, Edward J.
• Assistant Examiner(s): SONG, HOON K
• Application Number:
  US10/107,562
• Publication Number:
  US 20030185339A1
• Time in Patent Office: 1,042 Days
• Field of Search: 378/19, 378 21- 27, 378/98.8, 378/4, 250/363.04, 250/363.07, 250/363.08, 250/363.09, 250/366
• US Class Current: 378/19
• CPC Class Codes: G01N 2223/419 computed tomograph
• CPC Class Codes: G01N 23/046 using tomography, e.g. computed tomography [CT]
• CPC Class Codes: G06T 11/005 Specific pre-processing for tomographic reconstruction, e.g. calibration, source positioning, rebinning, scatter correction, retrospective gating
• CPC Class Codes: G06T 2211/436 Limited angle

Abstract

Disclosed are a method and apparatus for tomography of a curved surface in an object. One embodiment is a method that includes determining an expected distortion for each of a plurality of points in a projection of the curved surface, and correcting each of the plurality of points in the projection according to the expected distortion of that point by replacing pixel values in the uncorrected projection with corresponding interpolated pixel values at the expected positions.

Claims

1. A device for tomography of an object having a curved surface comprising:

a source of penetrating radiation;

a detector having a curved shape corresponding to the curved surface; and

a processor system configured to determine an expected distortion for each of a plurality of points in a projection of the curved surface onto the detector, and configured to correct each of the plurality of points in the protection according to the expected distortion of that point by replacing pixel values in the uncorrected projection with corresponding interpolated pixel values at the expected positions.

2. The device recited in claim 1, wherein said detector is deformable.

3. The device recited in claim 2, further comprising at least one actuator for shaping the deformable detector.

4. The device recited in claim 1, wherein said detector further comprises a plurality of spaced, flat detector elements.

5. The device recited in claim 4, further comprising a plurality of actuators wherein each actuator positions at least one of the detectors according to the shape of the curved surface.

6. A method for tomography of a curved surface in an object, comprising the steps of:

determining an expected distortion for each of a plurality of points in a projection of the curved surface onto a detector; and

correcting each of the plurality of points in the protection according to the expected distortion of that point by replacing pixel values in the uncorrected projection with corresponding interpolated pixel values at the expected positions.

7. The method recited in claim 6, further comprising the step of projecting energy through the object having the curved surface onto the detector having a curved shape corresponding to the curved surface.

8. The method recited in claim 7, further comprising the step of forming the detector into the curved shape.

9. The method recited in claim 7, further comprising the step of correcting the detected energy levels for brightness distortions.

10. The method recited in claim 6, wherein said determining step further comprises the steps of:

for each of the points in the projection, locating a corresponding reference point on a reference surface of the object;

for each of the reference points on the reference surface, finding a corresponding point on the curved surface of the object; and

determining an expected distortion in the projection for each point on the curved surface.

11. The method recited in claim 6, further comprising the steps of:

repeating the determining and correcting steps for a plurality of projections; and

reconstructively combining the corrected projections.

12. The method recited in claim 6, wherein the detector is curved.

13. The method recited in claim 6, wherein the reference surface is curved.

14. A device for tomography of a curved surface in an object, comprising:

means for determining an expected distortion of a plurality of points in a projection of the curved surface on a detector; and

means for correcting the projection according to the expected distortion of at least two of the points; and

means for replacing pixel values in the uncorrected projection with corresponding pixel values at corrected positions.

15. The device recited in claim 14, wherein the determining means further comprises:

means for designating a reference surface in the object, said reference surface having a shape corresponding to a surface of the detector;

means for determining a deviation from the reference surface for each of a plurality of points on the curved surface; and

means for determining an expected distortion in the projection for each of the points based upon the determined deviation from the reference surface.

16. The device recited in claim 15, further comprising:

means for repeating the determining and correcting steps for a plurality of projections; and

means for reconstructively combining the corrected projections.

17. The device recited in claim 16, wherein said combining means further comprises:

means for determining an offset for each of the corrected projections; and

means for tomosynthetically combining the adjusted and corrected projections using the determined offsets.

18. The device as recited in claim 17, wherein said combining further comprise means for adjusting a brightness of each corrected projection.

19. The device recited in claim 14, wherein the reference surface is curved.

20. A method for tomography of a curved surface in an object, comprising the steps of:

determining an expected distortion for each of a plurality of points in a projection of the curved surface onto a detector; and

correcting each of the plurality of points in the projection according to the expected distortion of that point, wherein said determining step further comprises the steps of;

for each of the points in the projection, locating a corresponding reference point on a reference surface of the object;

for each of the reference points on the reference surface, finding a corresponding point on the curved surface of the object; and

determining an expected distortion in the projection for each point on the curved surface.

21. The method recited in claim 20, wherein the correcting step includes the step of replacing pixel values in the uncorrected projection with corresponding interpolated pixel values at expected positions.

22. The method recited in claim 20, further comprising the step of forming the detector into the curved surface.

23. The method recited in claim 20, further comprising the step of correcting the detected energy levels for brightness distortions.

24. The method recited in claim 20, further comprising the steps of:

repeating the determining and correcting steps for a plurality of projections; and

reconstructively combining the corrected projections.

25. A device for tomography of a curved surface in an object, comprising:

means for determining an expected distortion of a plurality of points in a projection of the curved surface on a detector; and

means for correcting the projection according to the expected distortion of at least two of the points, wherein the determining means further comprises;

means for designating a reference surface in the object, said reference surface having a shape corresponding to a surface of the detector;

means for determining a deviation from the reference surface for each of the plurality of points on the curved surface; and

means for determining the expected distortion in the projection for each of the points based upon the determined deviation from the reference surface.

26. The device recited in claim 25, further comprising means for replacing pixel values in the uncorrected projection with corresponding pixel values at corrected positions.

27. The device recited in claim 25, further comprising:

means for repeating the determining and correcting steps for a plurality of projections; and

means for reconstructively combining the corrected projections.

28. The device recited in claim 27, wherein said combining means further comprises:

means for determining an offset for each of the corrected projections; and

means for tomosynthetically combining the adjusted and corrected projections using the determined offsets.

29. The device recited in claim 25, further comprising means for deforming the surface of the detector to correspond with the reference surface in the object.

30. The device recited in claim 25, further comprising means for correcting detected energy levels for brightness distortions.

31. The device recited in claim 30, wherein the detector further comprises a deforming detector that is deformed to correspond with the curved surface of the object.

32. A device for tomography of an object having a curved surface comprising:

a source of penetrating radiation;

a detector having a curved shape corresponding to the curved surface; and

a processor system configured to determine an expected distortion for each of a plurality of points in a projection of the curved surface onto the detector, and configured to correct each of the plurality of points in the projection according to the expected distortion of that point by locating a corresponding reference point on a reference surface of the object for each of the points in the projection, by finding a corresponding point on the curved surface of the object for each of the corresponding reference points on the reference surface, and by determining the expected distortion in the projection for each point on the curved surface.

33. A computer-readable medium having a program for tomography of a curved surface in an object, the program comprising logic configured to perform the steps of:

determining an expected distortion of a plurality of points in a projection of the curved surface on a detector; and

correcting the projection according to the expected distortion of at least two of the points, wherein the determining further comprises;

designating a reference surface in the object, said reference surface having a shape corresponding to a surface of the detector;

determining a deviation from the reference surface for each of the plurality of points on the curved surface; and

determining the expected distortion in the projection for each of the points based upon the determined deviation from the reference surface.

34. A computer-readable medium having a program for tomography of a curved surface in an object, the program comprising logic configured to perform the steps of:

determining an expected distortion for each of a plurality of points in a projection of the curved surface onto a detector; and

correcting each of the plurality of points in the projection according to the expected distortion of that point by replacing pixel values in the uncorrected projection with corresponding interpolated pixel values at expected positions.