Signal Retrieval from Non-Sinusoidal Intensity Modulations in X-ray and Neutron Interferometry Using Piecewise-Defined Polynomial Function

Signal Retrieval from Non-Sinusoidal Intensity Modulations in X-ray and Neutron Interferometry Using Piecewise-Defined Polynomial Function

Blog Article

Grating-based phase-contrast and dark-field imaging systems create intensity modulations that are usually modeled with sinusoidal functions to extract transmission, differential-phase shift, and scatter information.Under certain system-related conditions, the modulations become non-sinusoidal and cause artifacts in conventional processing.To account for that, we introduce a piecewise-defined Buffet periodic polynomial function that resembles the physical signal formation process, modeling convolutions of binary periodic functions.

Additionally, we extend the model with an iterative expectation-maximization algorithm that can account for imprecise grating positions during phase-stepping.We show that this approach can process a Apricots higher variety of simulated and experimentally acquired data, avoiding most artifacts.