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Grain Boundaries Imaged by Integration of Sobel Filtered Scanning Transmission Electron Micrographs
Applied Microscopy 2018;48:132-3
Published online December 28, 2018
© 2018 Korean Society of Microscopy.

Min-Chul Kang, Jinsu Oh, and Cheol-Woong Yang*

School of Advanced Material Science & Engineering, Sungkyunkwan University, Suwon 16419, Korea
Correspondence to: *Correspondence to: Yang CW,, Tel: +82-31-290-7362, Fax: +82-31-290-7371, E-mail:
Received December 25, 2018; Revised December 27, 2018; Accepted December 28, 2018.
This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

One of the most important factors determining the properties of a material is its grain size. However, unclear grain boundaries in the image hinder an accurate measurement of grain size. We demonstrate that grain boundaries existing in the images obtained by scanning transmission electron microscopy (STEM) can be clearly distinguished by applying a Sobel filter to a tilting series of STEM images of a hydrogenation-disproportionationdesorption-recombination processed Nd2Fe14B magnet sample.

Keywords : Sobel filter, Image processing, Poisson noise, Channeling contrast
  1. Pauli, L, Heikki, R, Tapio, S, Hannu, H, and Jani, R (2014). Influence of grain size distribution on the Hall-Petch relationship of welded structural steel. Materials Science & Engineering A. 592, 28-39.
  2. Sobel, I, and Feldman, G (1968). A 3×3 isotropic gradient operator for image processing a talk at the Stanford Artificial Project.

December 2018, 48 (4)
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