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鉴于我国各临床机构早期投入使用的CT设备已进入老化和故障期,提出了一种能应对探测器故障的CT图像重建的容错算法。该算法针对探测器故障导致的实测投影数据异常以及图像中进一步出现的环状伪影的去除问题进行了研究,提出对投影数据异常值具备容错机制的L1范数差,并利用凸优化领域的近端分裂理论构建出行处理型迭代算法。此外,通过向L1范数叠加全变分(TV)惩罚项,使新算法在去除环状伪影方面更具鲁棒性。数字模型和实际临床CT图像的重建实验表明:传统的L2范数重建受严重伪影影响,而L1范数和L1-TV范数能实现图像的完美重建。
Abstract：In order to continuously use the aging and faulty CT equipment purchased early in various clinical institutions of China,this paper proposes a fault-tolerant algorithm for medical CT image reconstruction dealing with failed detector. The study examines the measured projection data that are abnormal due to failed detectors and ring artifact reduction. The proposed fault-tolerant algorithm utilizes the L1 norm error function,and a row-action-type iterative algorithm is developed using the proximal splitting framework in convex optimization fields. Additionally,the new algorithm can become more robust in reducing ring artifacts by adding a weak total variation penalty item to L1 norm. The numerical phantom and actual clinical CT image reconstruction experiments demonstrate that the conventional L2 norm reconstruction is severely damaged by ring artifacts,whereas the L1 norm and L1-TV strategies can achieve an ideal image reconstruction.
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基本信息:
DOI：10.19573/j.issn2095-0926.202001002
中图分类号:TP391.41;R197.39
引用信息:
[1]董建,毕丹阳,杨耿煌等.探测器故障下医用CT图像重建的容错算法开发[J].天津职业技术师范大学学报,2020,30(01):7-12+25.DOI:10.19573/j.issn2095-0926.202001002.
基金信息:
天津市自然科学基金资助项目（18JCYBJC43600）;; 天津市留学人员择优资助项目（201819）;; 天津职业技术师范大学预研项目（KYQD1808）