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

• US 20060104536A1
• Filed: 11/17/2004
• Published: 05/18/2006
• Est. Priority Date: 11/17/2004
• Status: Active Grant

• Current Assignee: General Electric Company, Purdue Research Foundation (Purdue University), University of Notre DAME Du Lac
• Original Assignee: General Electric Company, Purdue Research Foundation (Purdue University), University of Notre DAME Du Lac
• Inventors: Bouman, Charles Addison, Thibault, Jean-Baptiste, Sauer, Ken David, Hsieh, Jiang
• Granted Patent: US 7,440,602 B2
• Time in Patent Office: Days
• US Class Current: 382/274
• 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.

2. A method in accordance with claim 1 further comprising generating a weight function η

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

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

_m to weigh an error term.

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

_m to weigh an error term in accordance with d[η

_m(y_m−

F_m(x))], where y_m is the mth projection integral, d is a scalar valued function, and F_m is a mth value of a transformation of an image space x.

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

_m to weigh an error term in accordance with |η

_m(y_m−

F_m(x))|², where y_m is the mth projection integral, and F_m is a mth value of a transformation of an image space x.

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

_m to weigh a data term used to modify a dynamically varying cost function.

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

assigning a quality factor of 1 when a cell is within specifications;

assigning a quality factor of 0 when a cell is unresponsive; and

assigning a quality factor greater than 0 and less than 1 when a cell is not within specifications and partially responsive.

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

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

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; 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 11, wherein said computer further configured to use the weight function η

_m to weigh an error term in accordance with η

_m*d(y_m−

F_m(x)), where y_m is the mth projection integral, d is a scalar valued function, and F_m is a mth value of a transformation of an image space x.

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

_m to weigh an error term in accordance with η

_m*|y_m−

F_m(x)|²,where y_m is the mth projection integral, and F_m is a mth value of a transformation of an image space x.

14. An imaging system in accordance with claim 9, wherein said computer further configured to using the weight function η

_m to weigh a data term used to modify a dynamically varying cost function.

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.

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 a quality factor of 1 when a cell is within specifications;

assign a quality factor of 0 when a cell is unresponsive; and

assign a quality factor greater than 0 and less than 1 when a cell is not within specifications and 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.