Reduction of Windmill Artifacts in Helical X-ray CT Images Based on Dual-domain Filtering and Improved Distance Transform

Abstract

In helical X-ray computed tomography (CT) imaging, under sampling in the z-axis direction will cause windmill artifacts, leading to serious image quality degradation and mistakes in diagnosis. In this paper, a method based on dual-domain filtering and improved distance transform is proposed to reduce the windmill artifacts in helical CT images. In this study, firstly CT projection data are generated by simulation and the helical CT images with windmill artifacts are reconstructed by the FDK reconstruction algorithm. Then, the reduction effect of windmill artifacts is analyzed by using bilateral filtering kernel of different radius. Finally, the kernel radius is adjusted according to the improved distance transform to reduce the windmill artifacts. In this study, the feasibility and effectiveness of the proposed method are preliminarily verified by computer simulation experiments. The proposed method can retain the details in the images of the scanned objects while reducing windmill artifacts in the helical CT images. We will further validate the performance of the proposed method in a real helical CT in the future.