Adaptive patch-based ring artifacts removal for photon-counting CT

Photon-counting computed tomography (PCCT) is superior in providing better CT image contrast than traditional CT technology. However, noticeable ring artifacts are more likely caused by the imperfect functioning of photon-counting detectors. This study proposes an efficient ring artifacts correction approach based on the unique characteristics of unwanted components in multi-domains. First, a patch-based signed statistic is utilized to identify the aberrant patches in the frequency space data of the sinogram data. Then, the adaptive patch (AP) filter and plausible patch filtering strategies are developed to correct undesirable patches. Third, an adaptive stripe (AS) filter is suggested in the spatial space to enhance the AP-filtered sinogram data. The experimental results indicate that the proposed methods outperform the state-of-the-art methods in artifact removal and structure preservation.