Optimizing disk registration algorithms for nanobeam electron diffraction strain mapping

Scanning nanobeam electron diffraction strain mapping is a technique by which the positions of diffracted disks sampled at the nanoscale over a crystalline sample can be used to reconstruct a strain map over a large area. However, it is important that the disk positions are measured accurately, as t...

Full description

Saved in:
Bibliographic Details
Published in:Ultramicroscopy 2017-05, Vol.176 (C), p.170-176
Main Authors: Pekin, Thomas C., Gammer, Christoph, Ciston, Jim, Minor, Andrew M., Ophus, Colin
Format: Article
Language:English
Subjects:
MATERIALS SCIENCE
Nanobeam electron diffraction
Strain measurement
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Scanning nanobeam electron diffraction strain mapping is a technique by which the positions of diffracted disks sampled at the nanoscale over a crystalline sample can be used to reconstruct a strain map over a large area. However, it is important that the disk positions are measured accurately, as their positions relative to a reference are directly used to calculate strain. In this study, we compare several correlation methods using both simulated and experimental data in order to directly probe susceptibility to measurement error due to non-uniform diffracted disk illumination structure. We found that prefiltering the diffraction patterns with a Sobel filter before performing cross correlation or performing a square-root magnitude weighted phase correlation returned the best results when inner disk structure was present. We have tested these methods both on simulated datasets, and experimental data from unstrained silicon as well as a twin grain boundary in 304 stainless steel.
ISSN:0304-3991
1879-2723
DOI:10.1016/j.ultramic.2016.12.021