单材质物体锥束CT成像的硬化校正

目前常用的FBP重建算法假定用以产生投影数据的X光是单能的,而实际上X光机或加速器发出的光并不是单能的。这就造成成像过程与重建算法的不匹配,导致硬化现象的产生。本文分析了这一研究领域的各种硬化校正方法,指出对单材质物体的硬化校正来说,线性化是其中较好的方法,它能够解决硬化校正的问题。本文对已有的线性化方法进行创新发展,解决了多项式阶数选择问题,将其应用推广到锥束CT成像,并通过实验验证了改进方法的实用性和有效性。

Beam Hardening Correction of Single-material Objects in CT Imaging

Currently FBP reconstruction algorithms assume that X-ray which is used to produce projection data is of monoenergy. This presumption is incorrect in reality, which causes the mismatch between the imaging process and the reconstruction algorithms, and leads to the beam hardening phenomenon. We analyze a variety of beam hardening correction algorithms and point out that single-material object linearization is a better method. An improved linearization method is proposed, which solves the problem of how to select the degree of the polynomial and extends the application range of polynomial fitting based on reprojection to cone-beam CT imaging. Finally, experiments are given to prove the practicality and validity of the proposed method.