Tomography of curved surfaces

• US 20030185339A1
• Filed: 03/27/2002
• Published: 10/02/2003
• Est. Priority Date: 03/27/2002
• Status: Active Grant

• Current Assignee: Agilent Technologies, Inc., Nidec Jue-Choung Electronics Company Limited
• Original Assignee: Agilent Technologies, Inc.
• Inventors: Reynolds, David C., Heumann, John M.
• Granted Patent: US 6,850,589 B2
• Time in Patent Office: Days
• 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

A device for tomography of curved surfaces is disclosed including a source, an object having a curved surface, and a detector having a curved shape corresponding to the curved surface. Also disclosed are a method and apparatus for tomography of a curved surface in an object, 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.

Claims

1. A device for tomography of curved surfaces comprising:

a source of penetrating radiation;

an object having a curved surface; and

a detector having a curved shape corresponding to the curved surface.

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

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

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

5. The device recited in claim 3, 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 curved surfaces, comprising the step of projecting energy through an object having a curved surface onto a detector having a curved shape corresponding to the curved surface.

7. The method recited in claim 6, further comprising the step of forming the detector into the curved shape.

8. The method recited in claim 6, further comprising the step of correcting the detected energy levels for brightness distortions.

9. 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.

10. The method recited in claim 9, 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 9, wherein the correcting step includes the step of replacing pixel values in the uncorrected projection with corresponding interpolated pixel values at the expected positions.

12. The method recited in claim 9, further comprising the steps of:

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

reconstructively combining the corrected projections.

13. The method recited in claim 9, wherein the detector is curved.

14. The method recited in claim 9, wherein the reference surface is curved.

15. 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.

16. The device recited in claim 15, 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.

17. The device recited in claim 15, wherein the correcting means includes means for replacing pixel values in the uncorrected projection with corresponding pixel values at corrected positions.

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

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

means for reconstructively combining the corrected projections.

19. The device recited in claim 18, 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.

20. The device recited in claim 15, wherein the reference surface is curved.

21. The device as recited in claim 19, wherein said combining further comprise means for adjusting a brightness of each corrected projection.