Micro-computed tomography (micro-CT) is a widely used state-of-the-art instrument employed to study the morphological structures of objects in various fields. However, its small field-of-view (FOV) cannot meet the pressing demand for imaging relatively large objects at high spatial resolutions. Recently, we devised a novel scanning mode called multiple source translation CT (mSTCT) that effectively enlarges the FOV of the micro-CT and correspondingly developed a virtual projection-based filtered backprojection (V-FBP) algorithm for reconstruction. Although V-FBP skillfully solves the truncation problem in mSTCT, it requires densely sampled projections to arrive at high-resolution reconstruction, which reduces imaging efficiency. In this paper, we developed two backprojection-filtration (BPF)-based algorithms for mSTCT: S-BPF (derivatives along source) and D-BPF (derivatives along detector). D-BPF can achieve high-resolution reconstruction with fewer projections than V-FBP and S-BPF. Through simulated and real experiments conducted in this paper, we demonstrate that D-BPF can reduce source sampling by 75% compared with V-FBP at the same spatial resolution, which makes mSTCT more feasible in practice. Meanwhile, S-BPF can yield more stable results than D-BPF, which is similar to V-FBP.

翻译：微计算机断层扫描（micro-CT）是一种广泛应用于各领域研究物体形态结构的先进仪器。然而，其有限的视场（FOV）无法满足高空间分辨率下对较大物体成像的迫切需求。近期，我们设计了一种称为多源平移CT（mSTCT）的新型扫描模式，有效扩大了micro-CT的FOV，并相应开发了基于虚拟投影的滤波反投影（V-FBP）重建算法。尽管V-FBP巧妙解决了mSTCT中的截断问题，但需要密集采样的投影才能实现高分辨率重建，从而降低了成像效率。本文针对mSTCT开发了两种基于反投影滤波（BPF）的算法：S-BPF（沿源导数）和D-BPF（沿探测器导数）。与V-FBP和S-BPF相比，D-BPF能用更少的投影实现高分辨率重建。通过本文进行的仿真和实际实验，我们证明在相同空间分辨率下，D-BPF相比V-FBP可将源采样量减少75%，这使得mSTCT在实际应用中更具可行性。同时，S-BPF能比D-BPF获得更稳定的结果，其性能与V-FBP相似。