Cause and correction methods of streak-type artifacts of CT image

Lots of streak-type artifacts exist in 3D CT (Computed Tomography) images after reconstruction, which do much harm to image quality and true flaw. After careful study, we found out these artifacts is caused by random defects in projections. This paper puts forward a method called relative threshold in Radon domain, which eliminates these artifacts by eliminating random defects in Radon domain. Experiment results proved this method is quite effective. It can eliminate almost all streak-type artifacts, improve image quality, and increase little to reconstruction burden (time cost). (authors)