A Variational Model for Removing Concentric Elliptical Artifacts from CT Images

In computed tomography (CT) imaging, artifacts will degrade the quality of reconstructed images. To solve this issue, in this paper we propose a method to remove concentric elliptical artifacts from CT images. This method is based on the idea of Directional total variation (DTV), which models the problem of elliptical artifact removal as an energy minimization problem, and establishes a variation-based model which is adapted the elliptical artifacts by analyzing the edge features of elliptical artifacts. Since the proposed model is a non-smooth convex optimization problem with a divisible structure, the alternating direction multiplier method (ADMM) is applied. Finally, the effectiveness of the model in removing elliptical artifacts is verified by simulation experiments.