Edge illumination X-ray phase contrast imaging with continuous mask motion

Edge illumination (EI) is an X-ray phase contrast imaging technique in which two absorbing masks are employed. Sensitivity for attenuation, refraction, and dark field contrast is achieved by acquiring images while discretely stepping one mask parallel to the other. However, this step-and-shoot acquisition strategy results in dead time between the acquisition of each frame, thereby increasing the scan duration. Continuous acquisition provides several advantages over a conventional step-and-shoot acquisition, such as a shorter scan time and improved mechanical stability. In this paper, an EI imaging strategy is presented in which the mask is moved continuously during acquisition. We prove that the standard EI imaging model allows for an unbiased extraction of the contrasts from data acquired with continuous mask motion, even when the motion is not explicitly modeled. This is supported by simulated and experimental data, demonstrating that EI with continuous mask motion does not require modifications to the imaging model.