Using sparsity information for iterative phase retrieval in x ray propagation imaging.
For iterative phase retrieval algorithms in near field x ray propagation imaging experiments with a single distance measurement, it is indispensable to have a strong constraint based on a priori information about the specimen; for example, information about the specimen's support. Recently, Loock and Plonka proposed to use the a priori information that the exit wave is sparsely represented in a certain directional representation system, a so called shearlet system. In this work, we extend this approach to complex valued signals by applying the new shearlet constraint to amplitude and phase separately. Further, we demonstrate its applicability to experimental data.
Optics express