In contrast, the CrysTBox tool diffractGUI fits a regular lattice to tens of detected reflections across whole diffraction pattern, which results in a higher accuracy. The d spacings, however, are measured between individual pairs of diffraction spots. Several brightest spots are used to measure d spacings and interplanar angles. It can detect diffraction spots in a very fast and robust way. In contrast, the presented approach reconstructs the reciprocal lattice using many detected spots distributed across the pattern.Īnother interesting tool, Auto SADP, is presented by Wu et al (2012 ▸). On the other hand, it is very sensitive to the localization of the central spot. This is a very fast and elegant approach, which reduces the number of spots localized by the user to one. The same author presents a tool for analysis of spot diffraction patterns (Mitchell, 2008 b ▸) employing a circular average centred on one of the diffraction spots. Localization of the ring centres is done via a Hough transform, which may be memory and computationally intensive in fully automatic mode. An interesting and robust tool for ring diffraction analysis was described by Mitchell (2008 a ▸). Some tools overcome these drawbacks by using a certain amount of automation. The manual localization of the image features is typically time consuming and often inaccurate. These programs require the user to perform some part of the analysis, to process some partial results or to localize the image features (diffraction spots or ring centre). Most of the software, however, requires a non-negligable amount of user intervention. There are a number of programs and scripts for the analysis of the spot diffraction (Mitchell, 2008 b ▸ Li, 2014 ▸ Wu et al., 2012 ▸ Stadelmann, 2004 ▸ Reid et al., 2011 ▸ Belletti et al., 2000 ▸ Lábár, 2005 ▸) and ring diffraction patterns (Mitchell, 2008 a ▸ Zhang et al., 2011 ▸ Li, 2007 ▸ Reid et al., 2011 ▸). The toolbox also provides an intuitive interface allowing the user to see, name and interpret various crystallographic problems. In the case of spot diffraction, the crystal lattice orientation in the direct space can be visualized and the holder tilt leading to an arbitrary sample orientation can be calculated. After setting the sample material, one click and about half a minute is enough to obtain the zone axis from the spot diffraction image or to identify the rings in the ring diffraction pattern. CrysTBox employs artificial intelligence and computer vision, resulting in tools which allow the vast majority of the input images to be analysed fully automatically in a very short time. Those images can be easily acquired however, their correct interpretation may be far from straightforward. The answers are often hidden in the images provided by a TEM. CrysTBox ( Crystallographic Tool Box) should answer those questions or help to reach the answers more quickly. Unfortunately, most of them also know how tedious it is to answer everyday elementary questions which may often look quite simple: Which material am I looking at and what is the sample orientation? How is the (102) plane situated in this orientation? How should I tilt my TEM (transmission electron microscope) holder to get the sample into the zone axis? Many other questions could follow. Most of those who have come across the field of crystallography know how exciting answering the questions raised in this domain can be. The toolbox is distributed as a standalone application, so it can be installed on the microscope computer and launched directly from DigitalMicrograph (Gatan Inc.). All the tools offer a graphical user interface. diffractGUI and cellViewer can be used together during a transmission electron microscopy session to determine the sample holder tilts required to reach a desired zone axis. Thirdly, cellViewer is an intuitive visualization tool which is also helpful for crystallographic calculations or educational purposes. Both diffractGUI and ringGUI employ methods of computer vision for a fast, robust and accurate analysis. Secondly, ringGUI identifies crystallographic planes corresponding to the depicted rings in the ring diffraction pattern and can select the sample material from a list of candidates. Firstly, diffractGUI determines the zone axis from selected area diffraction, convergent beam diffraction or nanodiffraction patterns and allows for indexing of individual reflections. Three tools for an automated analysis of electron diffraction pattern and crystallographic visualization are presented.
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