STEM Image Post-processing for Instability and Aberration Correction for Transfer Function Extension

Lewys Jones and Peter D Nellist (2012) Journal of Physics: Conference Series, 371, 012001

This manuscript was prepared for EMAG 2011. A presentation accompanying this manuscript was
presented as part of the Advances in Imaging and Spectroscopy Techniques session.

This content is also available Gold Open Access at the publishers webpage.

Abstract

Scanning transmission electron microscopy (STEM) images can be limited by either aberrations or, because of the technique's serial acquisition, by the effects of environmental instabilities. MatLab image-processing code was written which performs a two stage process to restore degraded high-resolution high-angle annular dark-field (HAADF) STEM images. Firstly, individual images were analysed to identify and correct for high-frequency scan noise; image resolution and signal-noise ratio (SNR) are used as performance metrics and were improved by up to 11.8% and 49% respectively. Secondly, a focal series was used to identify variations in information transfer as a function of defocus (aberrations) whereafter a single image was reconstructed yielding an increase in resolution and SNR of 9.88% and 205% respectively.