Detector pose measurement and correction methods for FPD-based cone-beam XCT system
-
摘要: 为了消除基于面阵探测器的锥束X射线计算机断层成像(XCT,X-ray Computed Tomography)检测系统中探测器的安装误差对重建断层图像的影响,使投影坐标系准确建立,并与重建坐标系精确配准,提出了基于椭圆拟合的平板探测器位姿参数的估计方法.并在此基础上,从锥束XCT的近似重建算法FDK(Feldkamp)出发,结合空间坐标变换原理,改进了重建算法中投影地址的计算方式,使之能在存在安装误差的情况下准确计算投影地址,重建出正确的断层图像.该方法简单有效,计算量小,无需对系统硬件进行调整.实验结果表明,利用该方法可以有效地消除由于探测器位姿引起的图像伪影.Abstract: To eliminate the artifacts in computed tomography (CT) images caused by the flat plane detector (FPD) pose error in cone-beam X-ray CT (XCT) testing system, methods of error measurement and correction were proposed. The ellipse fitting method based on the least squares technique was used to get the detector pose error which is essential for projection coordinate establishing and matching with the reconstruction coordinate accurately. The correction method improves the original Feldkamp (FDK) reconstruction algorithm in the calculation of projection address based on the spatial coordinate transformation theory by which the projection address could be calculated correctly. The methods are of less computation consuming and without hardware calibration. The experimental result proves that the methods could eliminate the artifacts effectively and help reconstruct CT image with high accuracy.
-
Key words:
- cone-beam scanning /
- detector pose /
- ellipse fitting /
- FDK reconstruction algorithm
-
[1] Roberts J A,Drage N A,Davies J.Effective dose from cone beam CT examinations in dentistry[J].British Journal of Radiology,2009,82(973):35-40 [2] Yan Guorui,Tian Jie,Zhu Shouping,et al.Fast cone-beam CT image reconstruction using GPU hardware[J].Journal of X-Ray Science and Technology,2008,16:225-234 [3] Periago D R,Scarfe W C,Moshiri M,et al.Linear accuracy and reliability of cone beam CT derived 3-dimensional images constructed using an orthodontic volumetric rendering program[J].Angle Orthodontist,2008,78(3):387-395 [4] Jiang Hsieh.计算机断层成像技术原理、设计、伪像和进展[M].北京:科学出版社,2006:27-65 Jiang Hsieh.Computed tomography principle,design,artifacts and recent advance[M].Beijing:Science Press,2006:27-65(in Chinese) [5] 侯颖.锥束XCT的定标方法研究 .大连:大连理工大学信息与通信工程学院,2010:28-42 Hou Ying.Research on calibration method in cone-beam XCT .Dalian:School of Information and Communication Engineering,Dalian University of Technology,2010:28-42(in Chinese) [6] Miao Hui,Wang Tingting,Zhao Huijuan,et al.Improvement based on FDK reconstruction algorithm of conebeam CT //Proc of SPIE.Belingham:SPIE,2010,7570:1-7 [7] 戎军艳.锥束微CT系统伪影校正与性能测试 .北京:中国科学院高能物理研究所,2009:62-64 Rong Junyan.Artifacts correction and performance tests of cone beam micro-CT system .Beijing:Institute of High Energy Physics, Chinese Academy of Science,2009:62-64(in Chinese) [8] 邹益民,汪渤.一种基于最小二乘的不完整椭圆拟合算法[J].仪器仪表学报,2006,27(7):808-812 Zou Yimin,Wang Bo.Fragmental ellipse fitting based on least square algorithm[J].Chinese Journal of Scientific Instrument,2006,27(7):808-812(in Chinese) [9] Mehmet Ali Aktas.Measuering shape ellipticity[J].Computer Analysis of Image and Patterns,2011,6854:170-177 [10] Hu Xinyu,Chen Zuobing,Zhang Daode,The application of randomized hough transform in ellipse image detection[J].Advanced Material Research,2010,159:388-392 [11] 吕洪赫,姚振杰,易卫东.基于对称性的最小二乘拟合随机椭圆检测法[J].电子测量技术,2011,34(5):37-41 Lü Honghe,Yao Zhenjie,Yi Weidong.Random least square fitting elliptic detection algorithm based on symmetry[J].Electronic Measurement Technology,2011,34(5):37-41(in Chinese) -
点击查看大图
计量
- 文章访问数: 1591
- HTML全文浏览量: 206
- PDF下载量: 500
- 被引次数: 0
下载:
