Image space compensation scheme for reducing artifacts

• US 6,570,951 B1
• Filed: 05/14/2002
• Issued: 05/27/2003
• Est. Priority Date: 05/14/2002
• Status: Expired due to Term

• Current Assignee: GE Medical Systems Global Technology Company LLC (GE Healthcare Technologies, Inc.)
• Original Assignee: GE Medical Systems Global Technology Company LLC (GE Healthcare Technologies, Inc.)
• Inventors: Hsieh, Jiang
• Primary Examiner(s): BRUCE, DAVID VERNON
• Application Number:
  US10/063,799
• Time in Patent Office: 378 Days
• Field of Search: 378/4, 378/8, 378/15, 378/901
• US Class Current: 378/4
• CPC Class Codes: A61B 6/032 Transmission computed tomography [CT]
• CPC Class Codes: A61B 6/5258 involving detection or reduction of artifacts or noise
• CPC Class Codes: G06T 11/008 Specific post-processing after tomographic reconstruction, e.g. voxelisation, metal artifact correction
• 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: Y10S 378/901 Computer tomography program or processor

Abstract

A method and system for reducing artifacts in an x-ray image generated by a computed tomography imaging system using an image space compensation scheme including obtaining reconstructed image data generated using an image reconstruction algorithm, determining a noise variation characteristic for the reconstruction algorithm, filtering the reconstructed image data so as to create smoothed image data and processing the smoothed image data and the reconstructed image data so as to create corrected image data. Also claimed is a medium encoded with a machine-readable computer program code for reducing artifacts in an x-ray image, the medium including instructions for causing controller to implement the aforementioned method.

Claims

1. A method for reducing artifacts in an x-ray image generated by a computed tomography imaging system using an image space compensation scheme comprising:

obtaining reconstructed image data generated using an image reconstruction algorithm;

determining a noise variation characteristic for said reconstruction algorithm;

filtering said reconstructed image data so as to create smoothed image data; and

processing said smoothed image data and said reconstructed image data so as to create corrected image data.

2. The method of claim 1, wherein said obtaining includes operating said computed tomography imaging system so as to generate raw projection data, wherein said reconstructed image data is responsive to said raw projection data.

3. The method of claim 2, wherein said obtaining includes reconstructing said raw projection data so as to create said reconstructed image data.

4. The method of claim 1, wherein said determining includes examining said reconstruction algorithm so as to identify said noise variation characteristic.

5. The method of claim 1, wherein said filtering includes filtering said reconstructed image data using a low pass filter, wherein said low pass filter is responsive to said reconstruction algorithm.

6. The method of claim 1, wherein said filtering includes filtering said reconstructed image data in a manner responsive to an applied scanning method, pre-patient filtering and an object being scanned.

7. The method of claim 1, wherein said processing includes calculating said corrected image data using a weighting function, wherein said weighting function is responsive to said noise variation characteristic.

8. The method of claim 1, wherein said processing includes calculating said corrected image data using a weighting function, wherein said weighting function is responsive to a center view projection angle.

9. The method of claim 8, wherein said center view projection angle is the projection angle of a center view formed with the image vertical axis.

10. The method of claim 1, wherein said processing includes calculating said corrected image data using a weighting function, wherein said weighting function is responsive to an applied scanning method, pre-patient filtering and an object being scanned.

11. The method of claim 1, wherein said processing includes calculating said corrected image data using a weighting function, wherein said weighting function is responsive to a correction parameter, wherein said correction parameter is determined experimentally.

12. The method of claim 1, wherein said reconstructed image data includes an image matrix having a matrix iso-center location, a mid-row index location and a mid-column index location.

13. The method of claim 12, wherein said processing includes calculating said corrected image data using a weighting function, wherein said weighting function is responsive to said matrix iso-center location, said mid-row index location, said mid-column index location, a CT imaging system full scan field of view and a reconstruction field of view.

14. A medium encoded with a machine-readable computer program code for reducing artifacts in an x-ray image generated by a computed tomography imaging system using an image space compensation scheme, said medium including instructions for causing a controller to implement a method comprising:

obtaining reconstructed image data generated using an image reconstruction algorithm;

determining a noise variation characteristic for said reconstruction algorithm;

filtering said reconstructed image data so as to create smoothed image data; and

processing said smoothed image data and said reconstructed image data so as to create corrected image data.

15. The medium of claim 14, wherein said obtaining includes operating said computed tomography imaging system so as to generate raw projection data, wherein said reconstructed image data is responsive to said raw projection data.

16. The medium of claim 15, wherein said obtaining includes reconstructing said raw projection data so as to create said reconstructed image data.

17. The medium of claim 14, wherein said determining includes examining said reconstruction algorithm so as to identify said noise variation characteristic.

18. The medium of claim 14, wherein said filtering includes filtering said reconstructed image data using a low pass filter, wherein said low pass filter is responsive to said reconstruction algorithm.

19. The medium of claim 14, wherein said filtering includes filtering said reconstructed image data in a manner responsive to an applied scanning method, pre-patient filtering and an object being scanned.

20. The medium of claim 14, wherein said processing includes calculating said corrected image data using a weighting function, wherein said weighting function is responsive to said noise variation characteristic.

21. The medium of claim 14, wherein said processing includes calculating said corrected image data using a weighting function, wherein said weighting function is responsive to a center view projection angle.

22. The medium of claim 14, wherein said processing includes calculating said corrected image data using a weighting function, wherein said weighting function is responsive to an applied scanning method, pre-patient filtering and an object being scanned.

23. The medium of claim 14, wherein said processing includes calculating said corrected image data using a weighting function, wherein said weighting function is responsive to a correction parameter, wherein said correction parameter is determined experimentally.

24. The medium of claim 14, wherein said processing includes calculating said corrected image data using a weighting function, wherein said weighting function is responsive to a CT imaging system full scan field of view, a reconstruction field of view and an image matrix having a matrix iso-center location, a mid-row index location and a mid-column index location.

25. A method for reducing artifacts in an image comprising:

obtaining an imaging system and an object to be scanned;

operating said imaging system so as to create projection data responsive to said object;

examining said projection data so as to determine if said projection data should be processed; and

processing said projection data using an image space compensation scheme wherein said compensation scheme, obtains reconstructed image data generated using an image reconstruction algorithm;

determines a noise variation characteristic for said reconstruction algorithm;

filters said reconstructed image data so as to create smoothed image data; and

processes said smoothed image data and said reconstructed image data so as to create corrected image data.

26. A system for reducing artifacts in an x-ray image comprising:

a gantry having an x-ray source and a radiation detector array, wherein said gantry defines an object cavity and wherein said x-ray source and said radiation detector array are rotatingly associated with said gantry so as to be separated by said object cavity;

a object support structure movingly associated with said gantry so as to allow communication with said object cavity; and

a processing device having an image space compensation scheme, wherein said compensation scheme, obtains reconstructed image data generated using an image reconstruction algorithm;

determines a noise variation characteristic for said reconstruction algorithm;

filters said reconstructed image data so as to create smoothed image data; and

processes said smoothed image data and said reconstructed image data so as to create corrected image data.

27. A system for reducing artifacts in an image using an image space compensation scheme comprising:

an imaging system;

an object disposed so as to be communicated with said imaging system, wherein said imaging system generates projection data responsive to said object; and

a processing device, wherein said processing device, obtains reconstructed image data generated using an image reconstruction algorithm;

determines a noise variation characteristic for said reconstruction algorithm;

filters said reconstructed image data so as to create smoothed image data; and

processes said smoothed image data and said reconstructed image data so as to create corrected image data.

28. The system of claim 27, wherein said object is a patient.

29. The system of claim 27, wherein said imaging system is a computed tomography imaging system.