TOPOLOGICAL LOCALISATION OF DEFECTS AT ATOMIC SCALE

Jean-Paul Jernot, Patricia Jouannot-Chesney, Christian Lantuéjoul, Gérard Nouet, Pierre Ruterana

Abstract

The problem addressed in this paper is the detection of defects on atomic structures. The procedure proposed is in two steps. At first a tessellation is built starting from the atoms. It consists of a partition of the space into cells, and is used to define the neighbourhood relationships between the atoms. Then, the local contribution to a topological parameter, namely the Euler-Poincare characteristic, is defined and measured for each cell. Within a regular tessellation, made of identical cells, this local contribution is equal to zero. Any local deviation from regularity corresponds to a tessellation containing cells with non-zero contributions. This allows us to locate the defects from a topological criterion and opens the way to a fully automatic detection of interfaces at atomic scale. The procedure is applied in 2D space for the detection of edge dislocations, grain boundaries and twins from HREM models and images. A 3D example is also given to illustrate its generality.

Keywords
defects; Euler-Poincare characteristic; HREM images; interfaces; tessellations; topology

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DOI: 10.5566/ias.v21.p191-198

Image Analysis & Stereology
EISSN 1854-5165 (Electronic version)
ISSN 1580-3139 (Printed version)