Single-material phase retrieval in grating-based X-ray imaging using a physics-based model

X-ray phase-contrast imaging utilizes wave-optical effects to generate image contrast, complementing traditional X-ray attenuation. This has proven particularly interesting for investigating biological samples with tissues that would otherwise produce weak attenuation contrast. Amongst the available techniques, grating-based imaging and propagation-based imaging stand out as two of the most promising methods to advance medical imaging and microscopy, respectively. In propagation-based imaging, approximating the object as a single material enables single-shot imaging with substantially reduced noise levels and enhanced image quality. Building on the success of the single-material approximation in propagation-based imaging, this study explores its potential application in grating-based imaging. We derive a physics-based model that directly integrates the single-material approximation into signal processing. Applying this approach to experimental data demonstrates its ability to reduce noise in the resulting composite image. Comparing our results with those from a single-material-based post-processing method reveals comparable outcomes, further validating the applicability of the single-material approximation in grating-based imaging.