OBJECTIVETo propose a new method for effectively and rapidly removing the ring artifacts in CT images based on image post-processing.

METHODSThe 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.

RESULTSSimulated and actual CT data experimental results demonstrated the efficiency of this method for removing artifacts, retaining the image fidelity and reducing the processing time.

CONCLUSIONThe new method can accurately recognize the position of the artifacts and effectively remove them to facilitate the clinical diagnosis.