Two-step phase retrieval method with unknown phase shift on non-absorbtion grating X-ray differential phase contrast imaging system

• DOI: 10.1016/j.nima.2012.07.013
• Publication Date: 2012-07-20T06:30:10Z
• Authors: X. Liu; J.C. Guo; Y.H. Lei; Y. Du; H.B. Niu
• Keywords: Differential phase; X-Ray Phase-Contrast Imaging

abstract Conventional phase retrieval methods for X-ray differential phase-contrast imaging are carried out withat least three interferograms. In this contribution, we present a novel two-step phase-shifting algorithmwith an arbitrary unknown phase shift between 0 and p . Based on the detecting model of a gratinginterferometer, the unknown phase shifts are extracted by a noniterative algorithm. Then the phasedistribution of the detected sample can be further obtained from the retrieval phase shift. This methodis experimentally validated based on non-absorbtion grating imaging system and the result verified itseffectiveness.& 2012 Elsevier B.V. All rights reserved. 1. IntroductionDue to their validity for weak absorbtion samples (e.g., softtissues), the X-ray phase-contrast techniques have received wideresearch interests around the world [3–5,1,2]. As a typical phasesensitive method, the differentia l phase contrast (DPC) imaging hasthe potential of application in medical imaging and industrial detec-tion owing to the low requirements on source-coherence, themechanical stability and the detector resolution [6–9]. The DPCimaging system can be regarded as a phase-shifting interferometry(PSI), so conventional PSI-based algorithms can be used in retrievingphase distribution [10]. The standard PSI requires a special phase shift2