title: [A method for rapidly removing ring artifacts in CT image].
abstract: OBJECTIVE
  To propose a new method for effectively and rapidly removing the ring artifacts in CT images based on image post-processing.
  
  
  METHODS
  The CT image with ring artifacts in the Cartesian coordinate was first transformed into an image with line artifacts in the polar coordinate. The image in the polar coordinate was then filtered by designing a one-dimensional filter to calculate the mean and variance of each pixel after filtering, which were compared with the variance threshold value and the pixel threshold value to determine the position of the artifacts for corrections accordingly. Finally, the polar coordinate image was converted into Cartesian coordinate image.
  
  
  RESULTS
  Simulated and actual CT data experimental results demonstrated the efficiency of this method for removing artifacts, retaining the image fidelity and reducing the processing time.
  
  
  CONCLUSIONS
  The new method can accurately recognize the position of the artifacts and effectively remove them to facilitate the clinical diagnosis.
authors.affiliation: Institute of Medical Instrument, School of Biomedical Engineering, Southern Medical University, Guangzhou 510515, China. qhl2006@fimmu.com
authors.forename: Hongliang
authors.initials: H
authors.lastname: Qi
authors.forename: Hong
authors.initials: H
authors.lastname: Hong
authors.forename: Yuan
authors.initials: Y
authors.lastname: Xu
authors.forename: Xin
authors.initials: X
authors.lastname: Zhen
authors.forename: Wenting
authors.initials: W
authors.lastname: Lu
authors.forename: Linghong
authors.initials: L
authors.lastname: Zhou
mesh_terms: D016477:Artifacts; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D014057:Tomography, X-Ray Computed