Computational techniques in propagation-based x-ray phase imaging

X-ray phase imaging utilizes a variety of techniques to render phase information as intensity contrast and these intensity images can in some cases be processed to retrieve quantitative phase. A subset of these techniques use free space propagation to generate phase contrast and phase can be recovered by inverting differential equations governing propagation. Two techniques to generate quantitative phase reconstructions from a single phase contrast image are described in detail, along with regularization techniques to reduce the influence of noise. Lastly, a recently developed technique utilizing a binary amplitude grid to enhance signal strength in propagation based techniques is described.