低分辨率外部信息的内X射线衍射层析成像
Interior X-ray diffraction tomography with low-resolution exterior information
摘要：
X射线衍射层析成像（XDT）解析宏观物体内的空间变化XRD轮廓，并且与传统的基于透射的计算机断层成像（CT）相比提供改进的材料对比度。然而，由于小的衍射截面，XDT遭受长的成像采集时间，这可能需要几十个小时的全扫描使用台式X射线管。在医学和工业成像应用中，通常仅需要感兴趣区域（ROI）内的XRD测量，这与减少成像时间和对样品的辐射剂量的需求一起，推动了仅扫描和重建样品内的内部区域的内部XDT系统的开发。内部问题没有唯一解，直接对截断投影数据进行反演往往会导致ROI重建误差较大。为了减少截断伪影，传统的基于衰减的内部重建问题依赖于ROI内的已知区域或分段常数约束，这并不适用于XDT中的所有样本。在这里，我们提出了一个准内部XDT计划，它结合了一小部分的投影信息，从外部区域，以协助内部重建。低分辨率的外部投影数据消除了对对象的先验知识的要求，并允许使用快速、广泛使用的滤波反投影算法来执行ROI重建，以便于集成到实时XDT成像模块中。
英文摘要：
X-ray diffraction tomography (XDT) resolves spatially-variant XRD profiles within macroscopic objects, and provides improved material contrast compared to the conventional transmission-based computed tomography (CT). However, due to the small diffraction cross-section, XDT suffers from long imaging acquisition time, which could take tens of hours for a full scan using a table-top X-ray tube. In medical and industrial imaging applications, oftentimes only the XRD measurement within a region-of-interest (ROI) is required, which, together with the demand to reduce imaging time and radiation dose to the sample, motivates the development of interior XDT systems that scan and reconstruct only an internal region within the sample. The interior problem does not have a unique solution, and a direct inversion on the truncated projection data often leads to large reconstruction errors in ROI. To reduce the truncation artifacts, conventional attenuation-based interior reconstruction problems rely on a known region or piecewise constant constraint within the ROI, which do not apply to all the samples in XDT. Here we propose a quasi-interior XDT scheme that incorporates a small fraction of projection information from the exterior region to assist interior reconstruction. The low-resolution exterior projection data obviates the requirement for prior knowledge on the object, and allows the ROI reconstruction to be performed with the fast, widely-used filtered back-projection algorithm for easy integration into real-time XDT imaging modules.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
