Generalized reverse projection method for grating‐based phase tomography

• Published in: Journal of synchrotron radiation Vol. 28; no. 3; pp. 854 - 863
• Main Authors: Wu, Zhao, Gao, Kun, Wang, Zhili, Wang, Shengxiang, Zhu, Peiping, Ren, Yuqi, Tian, Yangchao
• Format: Journal Article
• Language: English
• Published: 5 Abbey Square, Chester, Cheshire CH1 2HU, England International Union of Crystallography 01-05-2021; John Wiley & Sons, Inc
• Subjects: computed tomography; Field of view; Hypotheses; Imaging; phase retrieval; Projection; reverse projection; Synchrotron radiation; Synchrotrons; Tomography; X‐ray phase contrast; computed tomography; X-ray phase contrast; phase retrieval; reverse projection
• ISSN: 1600-5775; 0909-0495; 1600-5775
• DOI: 10.1107/S1600577521001806

The reverse projection protocol results in fast phase‐contrast imaging thanks to its compatibility with conventional computed‐tomography scanning. Many researchers have proposed variants. However, all these reverse projection methods in grating‐based phase‐contrast imaging are built on the hypothesis of the synchronous phase of reference shifting curves in the whole field of view. The hypothesis imposes uniformity and alignment requirements on the gratings, thus the field of view is generally limited. In this paper, a generalized reverse projection method is presented analytically for the case of non‐uniform reference in grating‐based phase tomography. The method is demonstrated by theoretical derivation, numerical simulations and synchrotron radiation experiments. The influence of imaging position to sensitivity, and the phase‐wrapping phenomenon are also discussed. The proposed method combines the advantages of the high efficiency of the reverse projection method and the universal applicability of the phase‐stepping method. The authors believe that the method would be used widely in fast and dose‐constrained imaging.
A generalized reverse projection method has been established analytically for grating‐based phase tomography with non‐uniform reference. The method combines the advantages of the high efficiency of the reverse projection method and the universal applicability of the phase‐stepping method.