Inline edge illumination X-ray phase contrast imaging through mask misalignment

Abstract

X-ray imaging is becoming more commonplace for inline industrial inspection, where a sample placed on a conveyor belt is translated through a scanning setup. However, the conventional X-ray attenuation contrast is often insufficient to characterize soft materials such as polymers and carbon reinforced components. Edge illumination (EI) is an X-ray phase contrast imaging technique that provides complementary differential phase and dark field contrasts, next to attenuation contrast. Combining multiple of these contrasts has been shown to improve industrial defect detection tasks. Unfortunately, conventional EI imaging is incompatible with an inline setup, as it requires moving part of the setup during acquisitions, while for inline scanning objects translate through a fixed inspection setup. Current solutions require either limiting the number of retrieved contrasts, or acquiring dedicated hardware. In this work, we demonstrate a method of inline EI imaging that does not limit the number of retrieved contrasts and does not require any new hardware. The method is validated through both simulation and experiment, demonstrating high flexibility and possible noise reduction, while successfully retrieving all three EI contrasts.