Image processing in high-resolution electron microscopy using the direct method. II. Image deconvolution

Abstract

A new method is proposed to estimate the defocus (Af) from a single electron micrograph (EM). The method has been tested by simulations using theoretical EM's calculated under different defocus conditions. The preliminary method is successful except when the EM is taken near the optimum defocus. This can be improved by making use of the information from the electron diffraction pattern. The method will be effective for radiation-sensitive materials.

Direct methods in electron crystallography: Image processing and solving incommensurate structures

“…they all have four heptagonal channels surrounding by hexagonal, pentagonal, tetragonal and trigonal channels. As has been shown by the simulating calculation (Han, Fan and Li, 1986), ED data can help improving the deconvolution result. An example using real experimental data is given on the left part of Figure 3.…”

“…It is seen from Figure 1b that, even in the case of kinematical diffraction, an EM will not necessary directly reflect structure details of the object. However a direct-method image deconvolution (Han, Fan and Li, 1986) On the other hand, a set of structure-factor magnitudes at 1Å resolution can be measured from the ED pattern. Ab initio direct-method phasing of these data resulted in the best E-map shown in Figure 1e.…”

“…Ishizuka (1974, 1975) first proposed a method for the deconvolution of a single EM under the weak-phase-object approximation. Inspired by this work, direct methods in X-ray crystallography were introduced into high resolution electron microscopy for the image deconvolution using a single EM (Li and Fan, 1979;Han, Fan and Li, 1986;Liu, Xiang, Fan, Tang, Li, Pan, Uyeda and Fujiyoshi, 1990).…”

Restoring defect structures in 3C-SiC/Si (001) from spherical aberration-corrected high-resolution transmission electron microscope images by means of deconvolution processing

“…These methods include exit wave reconstruction (Schiske, 1968;Coene et al, 1992Coene et al, , 1996Kirkland et al, 1995) and image deconvolution (Li and Fan, 1979;Han et al, 1986;Hu and Li, 1991;He et al, 1997). In the latter case the projected potential map is restored from a single http://dx.doi.org/10.1016/j.micron.2014.12.008 0968-4328/© 2015 Elsevier Ltd. All rights reserved.…”

Atomic resolution imaging of oxygen atoms close to heavy atoms by HRTEM and ED, using the superconductor SmFeAsO0.85F0.15 as an example

“…However the caused problems in increasing the accelerating voltage are not only a great increase in manufacturing and maintenance costs but also the serious radiation damage to the specimen. On the other hand, an alternative effective approach for the improvement of the point resolution is to reduce the spherical aberration coefficient (C s ) by hardware aberration correction, so-called C s -corrector (Haider et al, 1995) or by software method including electron crystallographic image processing (Li and Fan, 1979;Fan et al, 1985;Han et al, 1986;Hu and Li, 1991;Zou et al, 1996;Li, 2010;De Caro et al, 2010;Wan et al, 2012) and exit wave reconstruction Coene et al, 1996;Zandbergen and VanDyck, 2000;Chen et al, 2004;Allen et al, 2004;Hsieh et al, 2004). With a C scorrector, the point resolution can be extended to sub-angstrom level such that light atoms can be relatively easily detected by the negative C s imaging technique (Jia et al, 2003;Urban, 2008).…”