Comparison between different methods for parametric image estimation in analyzer-based phase contrast images

Analyzer-based phase contrast imaging (ABI) is an emerging imaging technique capable of visualizing complex interactions between X-rays and an object. Like many of the modern imaging techniques, ABI is a computed imaging method where parametric images are estimated from raw data. ABI raw data is acquired by measuring (sampling) the angular intensity profile (AIP) of the X-ray beam passed through the object at different positions of the analyzer crystal. ABI can simultaneously generate a number of planar parametric images containing information about absorption, refraction, and scattering properties of the object. In this manuscript, we compare several parametric image estimation methods with a newly proposed method based on the maximum likelihood estimation. In addition, we evaluate the impact of angular sampling positions on parametric image estimation accuracy as measured by bias and variance.