• Journal of Powder Materials
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• v.24 no.4
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• pp.285-291
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• 2017

We propose a custom analysis technique for the dark field (DF) image based on transmission electron microscopy (TEM). The custom analysis technique is developed based on the $DigitalMicrograph^{(R)}$ (DM) script language embedded in the Gatan digital microscopy software, which is used as the operational software for most TEM instruments. The developed software automatically scans an electron beam across a TEM sample and records a series of electron diffraction patterns. The recorded electron diffraction patterns provide DF and ADF images based on digital image processing. An experimental electron diffraction pattern is recorded from a IrMn polycrystal consisting of fine nanograins in order to test the proposed software. We demonstrate that the developed image processing technique well resolves nanograins of ~ 5 nm in diameter.

• Applied Microscopy
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• v.45 no.3
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• pp.150-154
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• 2015

Negative staining electron microscopy facilitates the visualization of small bio-materials such as proteins; thus, many electron microscopists have used this conventional method to visualize the morphologies and structures of biological materials. To achieve sufficient contrast of the materials, a number of imaging parameters must be considered. Here, we examined the effects of one of the fundamental imaging parameters, electron beam exposure time, on electron densities generated using transmission electron microscopy. A single site of a negatively stained biological sample was illuminated with the electron beam for different times (1, 2, or 4 seconds) and sets of micrographs were collected. Computational image processing demonstrated that longer exposure times provide better electron densities at the molecular level. This report describes technical procedures for testing parameters that allow enhanced evaluations of the densities of electron microscopy images.

• Applied Microscopy
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• v.44 no.4
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• pp.138-143
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• 2014

Transmission electron microscope (TEM) is an excellent tool for studying the structure and properties of nanostructured materials. As the development of $C_s$-corrected TEM, the direct analysis of atomic structures of nanostructured materials can be performed in the high-resolution transmission electron microscopy (HRTEM). Especially, fast Fourier transform (FFT) technique in image processing is very useful way to determine the crystal structure of HRTEM images in reciprocal space. To apply FFT technique in HRTEM analysis in more reasonable and friendly manner, we made a new circular region of interest (C-ROI) FFT script and tested it for several HRTEM analysis. Consequentially, it was proved that the new FFT application shows more quantitative and clearer results than conventional FFT script by removing the streaky artifacts in FFT pattern images. Finally, it is expected that the new FFT script gives great advantages for quantitative interpretation of HRTEM images of many nanostructured materials.

• Applied Microscopy
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• v.44 no.2
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• pp.74-78
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• 2014

Dislocation density and distribution in epitaxial GaAs layer on Si are evaluated quantitatively and effectively using image processing of transmission electron microscopy image. In order to evaluate dislocation density and distribution, three methods are introduced based on line-intercept, line-length measurement and our coding with line-scanning method. Our coding method based on line-scanning is used to detect the dislocations line-by-line effectively by sweeping a thin line with the width of one pixel. The proposed method has advances in the evaluation of dislocation density and distribution. Dislocations can be detected automatically and continuously by a sweeping line in the code. Variation of dislocation density in epitaxial GaAs films can be precisely analyzed along the growth direction on the film.

• 한국전자현미경학회:학술대회논문집
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• 2003.05a
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• pp.23-24
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• 2003

• Laser Solutions
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• v.12 no.2
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• pp.26-30
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• 2009

Scanning Electron Microscopy (SEM) includes high voltage generator, electron gun, column, secondary electron detector, scan coil system and image grabber. Column includes electron lenses (condenser lens and objective lens). Condenser lens generates fringe field, makes focal length and control spot size. Focal length represents property of lens. Objective lens control focus. Most of the electrons emitted from the filament, are captured by the anode. The portion of the electron current that leaves the gun through the hole in the anode is called the beam current. Electron beam probe is called the focused beam on the specimen. Because of the lens and aperture, the probe current becomes smaller than the beam current. It generate various signals(backscattered electron, secondary electron) in an interaction with the specimen atoms. In this paper, we describe the result of research to develop the core elements for low-resolution SEM.

• Applied Microscopy
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• v.30 no.3
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• pp.241-248
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• 2000

Electron microscopy has used for analysing the structure of protein over 30 years. Bacteriohodopsin and porins are used as examples to illustrate the progress that has recently been made in attaining resolutions which hitherto were regarded as exclusive to the realm of x-ray crystallography. To determine a protein structure used by electron microscopy, one must pass through a number of basic steps including preparation of specimen , data acquisition and data processing.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.11a
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• pp.100-103
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• 2008

한국기초과학지원연구원(KBSI, Korea Basic Science Institute)에서는 국내 유일의 초고전압투과전자현미경(HVEM, High Voltage Electron Microscopy)을 비롯하여 3대의 일반투과 전자현미경을 보유하고 있다. 전자현미경을 통하여 관찰된 이미지는 각 단계별로 tilting 되어 저장된 이미지로서 관찰자에게 보다 나은 관찰 환경의 구성을 위해 3D로의 reconstruction은 필수 과정이라고 할 수 있겠다. 이 과정 중 카메라 중심에서 벋어난 부분의 왜곡을 워핑기법을 통하여 최대한 감소시킨다. 이런 전처리 과정을 통하여 3D 구조물을 구성하게 되면 초기 이미지를 그대로 사용하는 것보다 한 단계 더 나은 결과물을 얻어낼 수 있다. 이미지 전처리를 이용한 전자현미경 볼륨 랜더링 시스템의 구축은 관찰자에게 보다 편리하며 빠른 실험 환경을 제공하여 줄 수 있고, 이해하기 쉽고 실제 모습에 가까운 형태의 실험 결과물을 접할 수 있게 된다.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.5
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• pp.122-128
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• 2007

The electric part of thermal SEM(Scanning Electron Microscopy) consists of high voltage generation, lens control, and image processing. Several methodologies for enhancing SEM image are addressed and those results are verified through analyses and experiments. The controller employes a DSP(Digital Signal Processing), making the system more flexible and convenient than the classical analogue based controller. In some parts based the analog circuit, there are inevitable sources of noise and image distortion. The experimental investigation is provided along with analytical proof to enhance the SEM image.

• Applied Microscopy
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• v.45 no.1
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• pp.23-31
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• 2015

Dark field (DF) transmission electron microscopy image has become a popular characterization method for two-dimensional material, graphene, since it can visualize grain structure and multilayer islands, and further provide structural information such as crystal orientation relations, defects, etc. unlike other imaging tools. Here we present microstructure of graphene, particularly, using DF imaging. High-angle grain boundary formation wass observed in heat-treated chemical vapor deposition-grown graphene on the Si substrate using patch-quilted DF imaging processing, which is supposed to occur by strain around multilayer islands. Upon the crystal orientation between layers the multilayer islands were categorized into the oriented one and the twisted one, and their local structure were compared. In addition information from each diffraction spot in selected area diffraction pattern was summarized.