X-ray CT metal artifacts reduction through curvature based sinogram inpainting

Abstract

We present a sinogram inpainting approach for X-ray computed tomography (CT) with the intent of reducing metal artifacts, where "inpainting" is a synonym for "image interpolation". Metal artifacts arise in CT when rays traverse the high attenuating objects such as metal bodies and portions of projection become unavailable. In this paper, we propose a sinogram inpainting method based on Euler's elastica and curvature for metal artifacts reduction, in which the unavailable data are regarded as an occlusion and can be inpainted inside the inpainting domain based on elastica interpolants. Numerical simulations demonstrate that, compared to conventional interpolation methods, the algorithm proposed connects the unavailable projection region more smoothly and accurately, and thus better reduces metal artifacts and more accurately reveals cross section structures, especially in the immediate neighborhood of the metallic objects.