Dark-field and directional dark-field on low coherence X-ray sources with random mask modulations: validation with SAXS anisotropy measurements

Abstract: Phase Contrast Imaging (PCI), Dark-Field (DF) and Directional Dark-Field (DDF) imaging are recent X-ray imaging modalities that have demonstrated their interest by providing access to information and contrasts different from those provided by conventional absorption X-ray imaging. However, access to these two types of images is currently limited because the acquisitions require the use of coherent sources such as synchrotron radiation or complicated optical setups to exploit the coherence requirements. This work demonstrates the possibility of efficiently performing phase contrast, dark-field and directional dark-field imaging on a low-coherence laboratory system equipped with a conventional X-ray tube, using a simple, fast and robust single-mask technique. The transfer to a low spatial coherence laboratory system was made possible by using random modulation based imaging (MoBI) and extending the low coherence system algorithm to retrieve dark-field and directional dark-field.