A multiscale Bayesian approach to quantification and denoising of energy-dispersive x-ray data

TL;DR

This paper introduces a multiscale Bayesian method for denoising and quantifying energy-dispersive X-ray data, improving accuracy and resolution in chemical mapping of materials at atomic scales.

Contribution

The paper presents a novel Bayesian approach that models Poisson noise and spatial correlations in EDX data, enhancing chemical map quality and resolution.

Findings

More accurate chemical maps from simulated data

Enhanced atomic resolution in experimental datasets

Better preservation of spatial details compared to standard methods

Abstract

Energy dispersive X-ray (EDX) spectrum imaging yields compositional information with a spatial resolution down to the atomic level. However, experimental limitations often produce extremely sparse and noisy EDX spectra. Under such conditions, every detected X-ray must be leveraged to obtain the maximum possible amount of information about the sample. To this end, we introduce a robust multiscale Bayesian approach that accounts for the Poisson statistics in the EDX data and leverages their underlying spatial correlations. This is combined with EDX spectral simulation (elemental contributions and Bremsstrahlung background) into a Bayesian estimation strategy. When tested using simulated datasets, the chemical maps obtained with this approach are more accurate and preserve a higher spatial resolution than those obtained by standard methods. These properties translate to experimental datasets, where the method enhances the atomic resolution chemical maps of a canonical tetragonal ferroelectric PbTiO3 sample, such that ferroelectric domains are mapped with unit-cell resolution.