本文提出了 一种基于等角多段探测器的非均匀采样计算机断层成像(Computed Tomography,CT)系统,并针对该系统推导了直接滤波反投影重建算法,分析了算法在处理非均匀采样CT数据时的局限性,特别是算法中权重函数的非光滑性对重建图像的影响.本文的理论推导和仿真实验结果显示:尽管直接滤波反投影(Filtered Back Projection,FBP)重建算法可能导致环状伪影,但通过适当的系统设计,这些伪影的影响可以被控制在可接受的范围内,并能保持图像的分辨率,使得基于等角多段探测器的非均匀采样CT的FBP算法具有一定的实用价值.本文研究成果为新型CT系统的设计和优化提供了理论依据和实践指导.
Abstract
This paper proposes a non-uniform sampling CT system based on equiangular multi-segment detectors,and derives a direct filtered back-projection(FBP)reconstruction algorithm for this system.It analyzes the limitations of the algorithm when dealing with non-uniformly sampled CT data,especially the impact of the non-smoothness of the weight function in the algorithm on reconstructed images.The theo-retical derivation and simulation results of this work show that,although the direct FBP algorithm may lead to ring artifacts,these artifacts can be controlled within an acceptable range through appropriate sys-tem design,which making the FBP algorithm based on equiangular multi-segment detectors for non-uni-formly sampled CT practical and capable of maintaining image resolution.The findings of this paper pro-vide a theoretical basis and practical guidance for the design and optimization of new CT systems.
维普
万方数据