Microsc. Microanal. Microstruct. 8, 41-57 (1997)
DOI: 10.1051/mmm:1997105

Analysis of Variations in Structure from High Resolution Electron Microscope Images by Combining Real Space and Fourier Space Information

Martin J. Hytch

Centre d'Études de Chimie Métallurgique, Centre National de Recherche Scientifique, 15 rue G. Urbain, 94407 Vitry-sur-Seine, France

Abstract
A new method is described for analysing variations in structure from high resolution electron microscope images. In Fourier theory, the image of a perfect crystal can be considered as the sum of sinusoidal lattice fringes having constant amplitude and phase given by the corresponding Fourier component. Imperfections are introduced by allowing these Fourier components to be a function of position, thus combining real space and reciprocal space information. It is shown how images can be obtained of the local value of the amplitude and phase of each major image periodicity. The amplitude and phase images are interpreted in terms of image detail and structural variations. Relationships are derived between the phase images and displacement fields due to a distortion of the lattice fringes and variations in the local reciprocal lattice vector. The meaning of the amplitude and phase images is illustrated by the analysis of experimental images of antiphase boundaries. Quantitative analysis of experimental images of carbon nanotubes is carried out using amplitude images and of strained metal multilayers using phase images.

PACS
0780 - Electron and ion microscopes and techniques.
6116D - Electron microscopy determinations of structures.
0230 - Function theory, analysis.

Key words
electron microscopy -- Fourier analysis -- image processing -- high resolution electron microscope images -- Fourier space information -- real space -- structure variations -- sinusoidal lattice fringes -- constant amplitude -- constant phase -- image periodicity -- phase images -- displacement fields -- local reciprocal lattice vector -- amplitude images -- strained metal multilayers


© EDP Sciences 1997