Methods, apparatus, and software to compensate for failed or degraded components

• US 7,440,602 B2
• Filed: 11/17/2004
• Issued: 10/21/2008
• Est. Priority Date: 11/17/2004
• Status: Active Grant

• Current Assignee: General Electric Company, Purdue Research Foundation (The Trustees of Purdue University (d/b/a Purdue University)), University of Notre DAME Du Lac
• Original Assignee: General Electric Company, Purdue Research Foundation (The Trustees of Purdue University (d/b/a Purdue University)), University of Notre DAME Du Lac
• Inventors: Bouman, Charles Addison, Thibault, Jean-Baptiste, Sauer, Ken David, Hsieh, Jiang
• Primary Examiner(s): AZARIAN, SEYED H
• Application Number:
  US10/990,921
• Publication Number:
  US 20060104536A1
• Time in Patent Office: 1,434 Days
• Field of Search: 382/128, 382/129, 382/130, 382/131, 382/132, 382/133, 382/168, 382/181, 382/232, 382/254, 382/260, 382/274, 382/275, 382/276, 382/100, 382/203, 382/220, 378/15, 378/16, 378/4, 378/19, 378/20, 378/21
• US Class Current: 382/128
• CPC Class Codes: A61B 6/027 characterised by the use of a particular data acquisition trajectory, e.g. helical or spiral
• CPC Class Codes: G06T 7/0004 Industrial image inspection

Abstract

A method for improving images of an imaging system including a plurality of detector cells includes assigning a quality factor for each detector cell.

Claims

1. A method for improving images of an imaging system including a plurality of detector cells, said method comprising:

assigning a quality factor for each detector cell wherein the quality factor is determined during a calibration process to indicate the “

health status”

of at least one of the plurality of detector cells, the quality factor being assigned a first value when the cell is within specifications, the quality factor being assigned a second value different than the first value when the cell is unresponsive; and

generating a weight function η

_m for a plurality of detector cells based on the quality factors of each particular detector cell.

2. A method in accordance with claim 1 further comprisingusing the weight function η

_m to weigh an error term.

3. A method in accordance with claim 2 further comprising using the weight function η

_m to generate a cost function used for the modification of a reconstructed image.

4. A method in accordance with claim 3 further comprising using the weigh function η

_m to generate a cost function used for the modification of the reconstructed image, wherein the cost function is minimized (or maximized) through at lease one pass through the data corresponding to the plurality of the detector cells.

5. A method in accordance with claim 2 further comprising using the iterative reconstruction techniques to produce an image.

6. A method in accordance with claim 1, wherein said assigning a quality factor for each detector cell comprises:

assigning to each detector cell a quality factor value and the second value when the cell is not within the specifications and is partially responsive.

7. A method in accordance with claim 6 further comprising generating a weight function η

_m for a particular detector cell based on the quality factor of that particular cell.

8. A method in accordance with claim 1, wherein said assigning a quality factor for each detector cell comprises:

assigning a logical “

1”

to the quality factor for each detector cell when the cell is within a predetermined specification; and

assigning a logical “

0”

to the quality factor for each detector cell when the cell is outside the predetermined specification.

9. An imaging system comprising:

a radiation source;

a detector array comprising a plurality of cells positioned to receive radiation from said source; and

a computer coupled to said detector array;

said computer configured to;

obtain from a memory a quality factor for each detector cell wherein the quality factor is determined during a calibration process to indicate the “

health status”

of at least one of the plurality of the detector cells, the quality factor being assigned a first value when the cell is within specifications, the quality factor being assigned a second value different than the first value when the cell is unresponsive;

generating a weight function η

_m for a plurality detector cells based on the quality factors of each particular detector cell; and

use the quality factors to reconstruct an image.

10. An imaging system in accordance with claim 9, wherein said computer further configured to reconstruct an image using a weight function η

_m for a particular detector cell wherein the weight function η

_m is based on the quality factor of that particular detector cell.

11. An imaging system in accordance with claim 10, wherein said computer further configured to use the weight function η

_m to weigh an error term.

12. An imaging system in accordance with claim 10, wherein said computer further configured to use the weight function η

_m to generate a cost function used for the modification of a reconstructed image.

13. An imaging system in accordance with claim 12, wherein said computer further configured to use the weight function η

_m to generate a cost function used for the modification of the reconstructed image, wherein the cost function is minimized (or maximized) through at least one pass through the data corresponding to the plurality of detector cells.

14. An imaging system in accordance with claim 9, wherein said computer further configured to use iterative reconstruction techniques to produce an image.

15. An imaging system in accordance with claim 9, wherein said radiation source comprises an x-ray source, and said computer configured to perform computed tomography (CT).

16. A computer readable medium encoded with a program configured to instruct a computer to assign a quality factor for each of a plurality of detector cells wherein the quality factor is determined during a calibration process to indicate the “

health status”

of at least one of the plurality of detector cells, the quality factor being assigned a first value when the cell is within specifications, the quality factor being assigned a second value different than the first value when the cell is unresponsive; and

generating a weight function η

_m for a plurality of detector cells based on the quality of each particular detector cell.

17. A computer readable medium in accordance with claim 16, wherein said program further configured to instruct the computer to generate a weight function η

_m for a particular detector cell based on the quality factor of that particular detector cell.

18. A computer readable medium in accordance with claim 16, wherein said program further configured to instruct the computer to:

assign to each detector cell a quality factor value between the first value and the second value when the cell is not within specifications and is partially responsive.

19. A computer readable medium in accordance with claim 18, wherein said program further configured to instruct the computer to generate a weight function η

_m for a particular detector cell based on the quality factor of that particular detector cell.

20. A computer readable medium in accordance with claim 19, wherein said program further configured to instruct the computer to using the weight function η

_m to weigh an error term.