Multi-modal and multi-scale non-local means method to analyze spectroscopic datasets

Niklas Mevenkamp; Katherine E MacArthur; Vasiliki Tileli; Philipp Ebert; Leslie J Allen; Benjamin Berkels; Martial Duchamp

doi:10.1016/j.ultramic.2019.112877

Multi-modal and multi-scale non-local means method to analyze spectroscopic datasets

Ultramicroscopy. 2020 Feb:209:112877. doi: 10.1016/j.ultramic.2019.112877. Epub 2019 Oct 30.

Authors

Niklas Mevenkamp¹, Katherine E MacArthur², Vasiliki Tileli³, Philipp Ebert⁴, Leslie J Allen⁵, Benjamin Berkels¹, Martial Duchamp⁶

Affiliations

¹ AICES Graduate School, RWTH Aachen University, Aachen, Germany.
² Ernst Ruska-Centrum, Forschungszentrum Jülich GmbH, Jülich, Germany.
³ Institute of Materials, École polytechnique fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
⁴ Peter Grünberg Institut, Forschungszentrum Jülich GmbH, Jülich, Germany.
⁵ Ernst Ruska-Centrum, Forschungszentrum Jülich GmbH, Jülich, Germany; School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia.
⁶ Ernst Ruska-Centrum, Forschungszentrum Jülich GmbH, Jülich, Germany; School of Materials Science and Engineering, Nanyang Technological University, Singapore. Electronic address: mduchamp@ntu.edu.sg.

PMID: 31884381
DOI: 10.1016/j.ultramic.2019.112877

Abstract

A multi-modal and multi-scale non-local means (M3S-NLM) method is proposed to extract atomically resolved spectroscopic maps from low signal-to-noise (SNR) datasets recorded with a transmission electron microscope. This method improves upon previously tested denoising techniques as it takes into account the correlation between the dark-field signal recorded simultaneously with the spectroscopic dataset without compromising on the spatial resolution. The M3S-NLM method was applied to electron energy dispersive X-ray and electron-energy-loss spectroscopy (EELS) datasets. We illustrate the retrieval of the atomic scale diffusion process in an Al_1-xIn_xN alloy grown on GaN and the surface oxidation state of perovskite nanocatalysts. The improved SNR of the EELS dataset also allows the retrieval of atomically resolved oxidation maps considering the fine structure absorption edge of LaMnO₃ nanoparticles.