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. Object-rotation is a classical scanning mode in micro-CT allowing data acquisition from different angles; however, its field-of-view (FOV) is primarily constrained by the size of the detector when aiming for high spatial resolution imaging. Recently, we introduced a novel scanning mode called multiple source translation CT (mSTCT), which effectively enlarges the FOV of the micro-CT system. Furthermore, we developed a virtual projection-based filtered backprojection (V-FBP) algorithm to address truncated projection, albeit with a trade-off in acquisition efficiency (high resolution reconstruction typically requires thousands of source samplings). In this paper, we present a new algorithm for mSTCT reconstruction, backprojection-filtration (BPF), which enables reconstructions of high-resolution images with a low source sampling ratio. Additionally, we found that implementing derivatives in BPF along different directions (source and detector) yields two distinct BPF algorithms (S-BPF and D-BPF), each with its own reconstruction performance characteristics. Through simulated and real experiments conducted in this paper, we demonstrate that achieving same high-resolution reconstructions, D-BPF can reduce source sampling by 75% compared with V-FBP. S-BPF shares similar characteristics with V-FBP, where the spatial resolution is primarily influenced by the source sampling.

翻译：微型计算机断层扫描（micro-CT）是一种广泛应用于各领域研究物体形态结构的先进设备。物体旋转是micro-CT中的经典扫描模式，可从不同角度采集数据；然而在高空间分辨率成像需求下，其视场主要受探测器尺寸限制。近期我们提出了一种新型扫描模式——多源平移CT（mSTCT），该模式有效扩大了micro-CT系统的视场。进一步地，我们开发了基于虚拟投影的滤波反投影（V-FBP）算法以处理截断投影问题，但该算法在采集效率方面存在权衡（高分辨率重建通常需要数千次源采样）。本文提出一种适用于mSTCT重建的新算法——反投影滤波（BPF），该算法能在低源采样比条件下实现高分辨率图像重建。此外，我们发现沿不同方向（源与探测器）实施BPF中的导数运算可衍生出两种特性各异的BPF算法（S-BPF与D-BPF），二者具有不同的重建性能特征。通过本文开展的仿真与真实实验，我们证明在实现同等高分辨率重建效果时，D-BPF相比V-FBP可将源采样量降低75%。而S-BPF与V-FBP具有相似特性，其空间分辨率主要受源采样率影响。