基于L1范数的微分相位衬度CT稀疏角度重建算法

微分相位衬度成像及其计算层析(CT)技术是近年出现的无损检测新方法。但是,相位衬度CT往往需要对样品进行多次扫描,这必将导致非常长的辐射时间和巨大的辐射剂量。稀疏角度重建在降低辐射剂量方面有着非常明显的优势,因此,研究针对相位衬度CT的稀疏角度重建算法就显得尤为重要。在分析了相位衬度CT的特点之后,将压缩感知理论引入相位衬度CT重建中,并在该理论框架下将L1约束融入代数迭代重建(ART)算法中,提出了一种微分相位衬度CT重建算法。数值模拟和实际实验表明,该方法可以根据少量投影数据给出较好的重建结果。

L1-Norm-Based Differential Phase-Contrast Computerized Tomography Reconstruction Algorithm with Sparse Angular Resolution

Differential phase contrast computerized tomography (DPC-CT) is a novel X-ray inspection method. However, DPC-CT usually requires several sampling attempts, which will inevitablly introduce unacceptabe long exposure time and huge X-ray doses. Sparse angular algorithms show significant advantage in reducing the exposure time and X-ray doses. Thus, the study of sparse angular DPC-CT is particularly important. After analyzing the characteristics of the DPC-CT, we introduce the compressive sensing theory into the DPC-CT reconstruction and propose a reconstruction algorithm for DPC-CT named as ART-L1 algorithm which fuse the L1 constraint into the ART algorithm. The numerical simulation and experimental results show that the ART-L1 algorithm can significantly improve the image quality of the sparse angular DPC-CT reconstructions.