【摘要】 FDK算法是应用在锥束CT系统中最有代表性的重建算法之一,该算法是在假设CT成像系统满足理想成像关系的条件下得到的。然而实际的锥束CT成像系统很难完全满足理想成像关系的要求,系统的几何失配会极大影响重建图像的质量,因此必须在重建之前对成像系统进行校准,获得系统的几何失配参数,并在重建过程中修正几何失配参数造成的影响。本文以之前所提出的锥束CT系统校准方法为基础,分析了在实际应用这种校准方法时需要注意的关键问题,然后利用所搭建的锥束XCT系统得到实际的校准结果和重建结果。结果证明之前所提出的应用于锥束XCT系统的校准方法对于测量系统的几何失配参数是有效可行的。更多还原

【Abstract】 The FDK algorithm is a classic cone-beam approximate reconstruction algorithm,which has been widely used in practice.Ideal imaging geometry is a basic condition in the application of the FDK algorithm.However,it is difficult to satisfy this condition in a practical cone-beam CT system.Reconstructed images will suffer from artifacts caused by the misaligned geometry of the CT system.Therefore,calibration of the CT system in advance is an important and necessary task.Misaligned parameters of the CT system will be taken into the reconstruction algorithm after calibration to improve image qualities in the case of the misaligned CT system.Key points on application of the proposed calibration method for cone-beam CT are discussed deeply in this paper.And calibration result and reconstructed results of an X-ray cone-beam CT are given which prove the validity of the proposed calibration method.更多还原