Ring artifact correction for X-ray computed tomography

In this paper, a novel preprocessing technique is proposed for the correction of ring artifact in X-ray CT image. By fitting each projection in sinogram image with piecewise polynomial, a set of candidate correction factors for mis-calibrated detector is created and then the factor with maximum probability occurrence is picked out to rectify the projection data. Principle and procedure of the method is illustrated. Tests under different condition show that, sparse or continuous ring artifact in the CT image can both be well rectified effectively, while spatial resolution of the image preserved. CT images for multi-material object can also be corrected by the method.