Maximum a posteriori estimation of crystallographic phases in X-ray diffraction tomography

Area of Science:

• Materials Science
• Crystallography
• Imaging Science

Background:

• X-ray diffraction tomography (XRD-T) is crucial for analyzing polycrystalline materials.
• Conventional methods face challenges with artifacts, noise, and undersampling.

Purpose of the Study:

• To develop a robust maximum a posteriori (MAP) approach for XRD-T.
• To improve the reconstruction of 3D crystallographic phase and orientation distributions.

Main Methods:

• The MAP approach maximizes a posteriori density, incorporating a Poisson log-likelihood.
• An a priori term enforces solution properties like smoothness and local continuity.
• The method was validated using experimental data from a porcine vertebra sample.

Main Results:

• Significant reduction in aliasing and streaking artifacts observed.
• Improved robustness to noise and undersampling compared to traditional methods.
• Demonstrated potential for reduced data acquisition times and enhanced beamtime efficiency.

Conclusions:

• The proposed MAP approach offers superior performance for XRD-T.
• This method advances the analysis of complex polycrystalline materials.
• It paves the way for more efficient and accurate materials characterization.