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A Search/Match Procedure for Electron Diffraction Data Based on Pattern Matching in Binary Bit Maps*

Published online by Cambridge University Press:  10 January 2013

Martin J. Carr ,
William F. Chambers  and
David Melgaard
Martin J. Carr
Affiliation:
Sandia, National Laboratories, Albuquerque, New Mexico 87185, U.S.A.
William F. Chambers
Affiliation:
Sandia, National Laboratories, Albuquerque, New Mexico 87185, U.S.A.
David Melgaard
Affiliation:
J&M Systems, Ltd., Albuquerque, New Mexico 87185, U.S.A.
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Abstract

A unique file structure and search algorithm have been developed for the purpose of obtaining matches between experimental electron diffraction and qualitative energy dispersive X-ray compositional data from an unknown crystalline phase and the reference data in the JCPDS Powder Diffraction File. The reference data for over 32,000 inorganic compounds from sets 1–33 were compressed and stored in binary format as bit pattern maps. The entire data set and searching programs require less than 4 Mbyte and retain the precision appropriate for electron diffraction analysis. The search algorithm, written in both RT-11 FORTRAN and Flextran, is based on pattern matching between bit maps obtained for the unknown and reference compounds for both composition and diffraction data. Special attention is given to double diffraction effects commonly encountered in electron diffraction analysis. The programs run on an interactive basis on a microcomputer dedicated to the X-ray energy dispersive spectrometer on an analytical electron microscope. A typical search takes about 15 seconds to run and extracts about 10–15 different compounds.

Type
Research Article
Information
Powder Diffraction , Volume 1 , Issue 3 , September 1986 , pp. 226 - 234
Copyright
Copyright © Cambridge University Press 1986

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