Method for removing rings and partial rings in computed tomography images
US6819734B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Nov 8, 2002 |
| Grant date | Nov 16, 2004 |
| Priority date | — |
| Expiry date | May 1, 2023 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S378/901
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An algorithmic method is used for suppressing artifacts in computed tomography raw data, on the basis of the determination and subsequent subtraction of a correction sinogram from a measured starting sinogram. The method includes high-pass filtering of a starting sinogram in the channel direction, and low-pass filtering in the projection direction in order to improve the signal-to-noise ratio. Thereafter, the magnitude of a weighted gradient of each data point in the low-pass-filtered sinogram is formed, both in the projection direction and symmetrically about the corresponding channel axis. The data point is eliminated if the change amplitude thereof exceeds a first defined threshold value. Residual data points are removed in the low-pass-filtered sinogram if their amplitude exceeds a second defined threshold value, and low-pass filtering of the resulting sinogram occurs in the form of averaging in the projection direction. The correction sinogram thus obtained is finally subtracted from the starting sinogram.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.