AstroEBSD: exploring new space in pattern indexing with methods launched from an astronomical approach

Electron backscatter diffraction (EBSD) is a technique used to measure crystallographic features in the scanning electron microscope. The technique is highly automated and readily accessible in many laboratories. EBSD pattern indexing is conventionally performed with raw electron backscatter patterns (EBSPs). These patterns are software processed to locate the band centres (and sometimes edges) from which the crystallographic index of each band is determined. Once a consistent index for many bands are obtained, the crystal orientation with respect to a reference sample & detector orientation can be determined and presented. Unfortunately, due to challenges related to crystal symmetry, there are limited available pattern indexing approaches and this has likely hampered open development of the technique. In this manuscript, we present a new method of pattern indexing, based upon a method with which satellites locate themselves in the night sky, and systematically demonstrate its effectiveness using dynamical simulations and real experimental patterns. The benefit of releasing this new algorithm is demonstrated as we utilise this indexing process, together with dynamical solutions, to provide some of the first accuracy assessments of an indexing solution. In disclosing a new indexing algorithm, and software processing tool-kit, we hope this opens up EBSD developments to more users. The software code and example data is released alongside this article for 3rd party developments.

[1]  N. C. Krieger Lassen.  Source point calibration from an arbitrary electron backscattering pattern , 1999 .

[2]  Marc De Graef,et al.  Error analysis of the crystal orientations obtained by the dictionary approach to EBSD indexing. , 2017, Ultramicroscopy.

[3]  N. C. Krieger Lassen,et al.  Automatic localisation of electron backscattering pattern bands from Hough transform , 1996 .

[4]  N. C. KRIEGER LASSEN,et al.  Calibration of an electron back‐scattering pattern set‐up , 1993 .

[5]  Mukul Kumar,et al.  Electron Backscatter Diffraction in Materials Science , 2000 .

[6]  R. Fortunier,et al.  A 3D Hough transform for indexing EBSD and Kossel patterns , 2008, Journal of microscopy.

[7]  Raynald Gauvin,et al.  Development of Tools to Increase the Spatial Resolution of EBSD Maps , 2009, Microscopy and Microanalysis.

[8]  S. Zaefferer,et al.  Characterization of order domains in γ-TiAl by orientation microscopy based on electron backscatter diffraction , 2009 .

[9]  Daniele Mortari,et al.  A Survey on Star Identification Algorithms , 2009, Algorithms.

[10]  Zaven Arzoumanian,et al.  An astronomical pattern-matching algorithm for computer-aided identification of whale sharks Rhincodon typus , 2005 .

[11]  Jon Alkorta,et al.  Limits of simulation based high resolution EBSD. , 2013, Ultramicroscopy.

[12]  Angus J. Wilkinson,et al.  Strains, planes, and EBSD in materials science , 2012 .

[13]  E. Groth,et al.  A pattern-matching algorithm for two-dimensional coordinate lists. [for stellar positions] , 1986 .

[14]  R. A. Schwarzer.  A Review of the Analysis of Local Texture by ELectron Diffraction , 1991 .

[15]  Robert A. Schwarzer,et al.  The Determination of Local Texture by Electron Diffraction–A Tutorial Review , 1993 .

[16]  Alfred O. Hero,et al.  A Dictionary Approach to Electron Backscatter Diffraction Indexing* , 2015, Microscopy and Microanalysis.

[17]  SHOJI NISHIKAWA,et al.  Diffraction of Cathode Rays by Calcite. , 1928, Nature.

[18]  Marc De Graef,et al.  Dictionary Indexing of Electron Channeling Patterns , 2017, Microscopy and Microanalysis.

[19]  Aimo Winkelmann,et al.  Dynamical Simulation of Electron Backscatter Diffraction Patterns , 2009 .

[20]  Krieger Lassen.  Automatic high‐precision measurements of the location and width of Kikuchi bands in electron backscatter diffraction patterns , 1998 .

[21]  N. C. Krieger Lassen,et al.  The relative precision of crystal orientations measured from electron backscattering patterns , 1996 .

[22]  W. Kabsch.  A discussion of the solution for the best rotation to relate two sets of vectors , 1978 .

[23]  A. Saiani,et al.  Microscopy and Microanalysis , 2017, Microscopy Today.

[24]  Michael A. Groeber,et al.  Consistent representations of and conversions between 3D rotations , 2015 .

[25]  G. Nolze.  Image distortions in SEM and their influences on EBSD measurements. , 2007, Ultramicroscopy.

[26]  A. Wilkinson,et al.  Factors affecting the accuracy of high resolution electron backscatter diffraction when using simulated patterns. , 2010, Ultramicroscopy.

[27]  Brent L. Adams,et al.  ADVANCES IN AUTOMATIC EBSP SINGLE ORIENTATION MEASUREMENTS , 1993 .

[28]  D. W. Pashley,et al.  High-angle Kikuchi patterns , 1954, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.

[29]  Brent L. Adams,et al.  Automatic analysis of electron backscatter diffraction patterns , 1992 .

[30]  Richard O. Duda,et al.  Use of the Hough transformation to detect lines and curves in pictures , 1972, CACM.

[31]  W. Kabsch.  A solution for the best rotation to relate two sets of vectors , 1976 .

[32]  Angus J. Wilkinson,et al.  Tutorial: Crystal orientations and EBSD — Or which way is up? , 2016 .

[33]  Xiaodong Tao,et al.  Errors, Artifacts, and Improvements in EBSD Processing and Mapping , 2005, Microscopy and Microanalysis.

[34]  Brent L. Adams,et al.  Orientation Imaging Microscopy: New Possibilities for Microstructural Investigations Using Automated BKD Analysis , 1994 .

[35]  Robert A. Schwarzer,et al.  Texture analysis by electron diffraction , 1991 .