Methods and apparatus for artifact reduction

• US 7,865,006 B2
• Filed: 07/22/2008
• Issued: 01/04/2011
• Est. Priority Date: 12/30/2003
• Status: Expired due to Term

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Fox, Stanley Haim, Hsieh, Jiang
• Primary Examiner(s): Le; Vu
• Assistant Examiner(s): BLOOM, NATHAN J
• Application Number:
  US12/177,641
• Publication Number:
  US 20080292173A1
• Time in Patent Office: 896 Days
• Field of Search: 382/100, 382/128, 382130-132, 378/1, 378 4- 20, 378/901, 348/61, 348/143, 345418-419, 345/501
• US Class Current: 382/131
• 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 2207/10081 Computed x-ray tomography [CT]
• CPC Class Codes: G06T 2207/30004 Biomedical image processing
• CPC Class Codes: G06T 5/20 using local operators
• CPC Class Codes: G06T 5/70 Denoising; Smoothing
• CPC Class Codes: G06V 10/30 Noise filtering
• CPC Class Codes: Y10S 378/901 Computer tomography program or processor

Abstract

A method for facilitating a reduction in image artifacts is provided. The method includes receiving data regarding a scan of an object, reconstructing a plurality of images using the received data to form a three-dimensional image space, determining an orientation for a maximum intensity pixel operation, locating the maximum intensity pixels within a plurality of ray paths in accordance with the determined orientation, and filtering around each maximum intensity pixel along each ray path.

Claims

1. A method for reducing image artifacts in image data acquired using a Computed Tomography (CT) imaging system, said method comprising:

receiving, at a computer, the acquired image data regarding a scan of an object;

reconstructing a plurality of images using the received data to form a three-dimensional image space;

determining an orientation for a maximum intensity pixel operation;

locating a maximum intensity pixel within a ray path in accordance with the determined orientation, wherein the maximum intensity pixel has adjacent pixels;

determining adjacent pixels having an intensity within a predetermined value of an intensity of the maximum intensity pixel;

filtering around the maximum intensity pixel along the ray path using the computer to exclude pixels other than the determined adjacent pixels having an intensity within the predetermined value of the intensity of the maximum intensity pixel; and

determining an average intensity of the adjacent pixels within the predetermined range of the intensity of the maximum intensity pixel and the maximum intensity pixel.

2. A method in accordance with claim 1 wherein filtering around the maximum intensity pixel along the ray path comprises using a low pass filter.

3. A method in accordance with claim 1 wherein filtering around the maximum intensity pixel along the ray path comprises using an adaptive filter.

18. A method in accordance with claim 1 wherein filtering around the maximum intensity pixel along the ray path comprises modifying an amount of filtering based on a local noise property of each reconstructed image.

4. A method for reducing image artifacts in image data acquired using a Computed Tomography (CT) imaging system, said method comprising:

receiving, at a computer, data regarding a scan of an object;

reconstructing, using the computer, a plurality of images using the received data to form a three-dimensional image space;

determining an orientation for a maximum intensity pixel operation, wherein the orientation is at an angle relative to a reconstructed image plane;

locating a maximum intensity pixel within a ray path in accordance with the determined orientation, wherein the maximum intensity pixel has adjacent pixels;

determining adjacent pixels having an intensity within a predetermined value of an intensity of the maximum intensity pixel;

filtering around a maximum intensity pixel using the computer to exclude pixels other than the determined adjacent pixels having an intensity within the predetermined value of the intensity of the maximum intensity pixel; and

determining an average intensity of the adjacent pixels within the predetermined range of the intensity of the maximum intensity pixel and the maximum intensity pixel.

5. A method in accordance with claim 4 wherein filtering around a maximum intensity pixel comprises using a low pass filter.

6. A method in accordance with claim 4 wherein filtering around a maximum intensity pixel comprises using an adaptive filter.

17. A method in accordance with claim 4 wherein filtering around a maximum intensity pixel comprises including in the filter at least a second pixel of the adjacent pixels, wherein the at least a second pixel has an intensity within the pre-determined value from the maximum intensity pixel.

7. An imaging system comprising:

a radiation source;

a radiation detector; and

a computer operatively coupled to said radiation source and said radiation detector, said computer configured to;

receive data regarding a scan of an object;

reconstruct a plurality of images using the received data to form a three-dimensional image space;

determine an orientation for a maximum intensity pixel operation;

locate a maximum intensity pixel within a ray path in accordance with the determined orientation, wherein the maximum intensity pixel has adjacent pixels;

determine adjacent pixels having an intensity within a predetermined value of an intensity of the maximum intensity pixel;

filter around the maximum intensity pixel along the ray path to exclude pixels other than the determined adjacent pixels having an intensity within the predetermined value of the intensity of the maximum intensity pixel; and

determine an average intensity of the adjacent pixels within the predetermined range of the intensity of the maximum intensity pixel and the maximum intensity pixel.

8. A system in accordance with claim 7 wherein said computer is configured to filter around the maximum intensity pixel along the ray path using a low pass filter.

9. A system in accordance with claim 7 wherein said computer is configured to include in the filter at least a second pixel of the adjacent pixels, wherein the at least a second pixel has an intensity within a pre-determined value from the maximum intensity pixel.

10. A system in accordance with claim 7 wherein said computer is configured to filter around the maximum intensity pixel along the ray path using an adaptive filter.

11. A system in accordance with claim 7 wherein said computer is configured to modify an amount of filtering based on a local noise property of each reconstructed image.

12. An imaging system comprising:

a radiation source;

a radiation detector; and

a computer operatively coupled to said radiation source and said radiation detector, said computer configured to;

receive data regarding a scan of an object;

reconstruct a plurality of images using the received data to form a three-dimensional image space;

determine an orientation for a maximum intensity pixel operation, wherein the orientation is at an angle relative to a reconstructed image plane;

locate a maximum intensity pixel within a ray path in accordance with the determined orientation, wherein the maximum intensity pixel has adjacent pixels;

determine adjacent pixels having an intensity within a predetermined value of an intensity of the maximum intensity pixel;

filter around a maximum intensity pixel to exclude pixels other than the determined adjacent pixels having an intensity within the predetermined value of the intensity of the maximum intensity pixel; and

determine an average intensity of the adjacent pixels within the predetermined range of the intensity of the maximum intensity pixel and the maximum intensity pixel.

13. A system in accordance with claim 12 wherein said computer is configured to filter around the maximum intensity pixel using a low pass filter.

14. A system in accordance with claim 12 wherein said computer is configured to include in the filter at least a second pixel of the adjacent pixels, wherein the at least a second pixel has an intensity within a pre-determined value from the maximum intensity pixel.

15. A system in accordance with claim 12 wherein said computer is configured to filter around the maximum intensity pixel-using an adaptive filter.

16. A system in accordance with claim 12 wherein said computer is configured to modify an amount of filtering based on a local noise property of each reconstructed image.