Inter-period phase-stepping approach for X-ray grating-based imaging

X-ray grating-based imaging is a powerful nondestructive tool in many fields. It works well with conventional X-ray tubes and multiple information, that is the attenuation image, the phase-contrast image and the dark-field image, can be obtained in a single scanning. Phase-stepping approach is the gold standard for information retrieval. One of the gratings moves relatively in the along the transverse direction. In this paper, an inter-period phase-stepping approach is proposed, which enables larger phase-stepping distance of the gratings. This approach can be realized by adopting multiple x-ray sources, e.g. the distributed x-ray source. In this case, the mechanical movement of the gratings can be replaced by the successive exposure of the multiple x-ray source, overcoming the time-consuming difficulty and eliminating the dependence of the high-resolution linear stage. Experimental results can verify the feasibility of the method.