Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA.
Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA.
Ultramicroscopy. 2020 Feb;209:112876. doi: 10.1016/j.ultramic.2019.112876. Epub 2019 Oct 28.
Accurate pattern center determination has long been a challenge for the electron backscatter diffraction (EBSD) community and is becoming critically accuracy-limiting for more recent advanced EBSD techniques. Here, we study the parameter landscape over which a pattern center must be fitted in quantitative detail and reveal that it is both "sloppy" and noisy, which limits the accuracy to which pattern centers can be determined. To locate the global optimum in this challenging landscape, we propose a combination of two approaches: the use of a global search algorithm and averaging the results from multiple patterns. We demonstrate the ability to accurately determine pattern centers of simulated patterns, inclusive of effects of binning and noise on the error of the fitted pattern center. We also demonstrate the ability of this method to accurately detect changes in pattern center in an experimental dataset with noisy and highly binned patterns. Source code for our pattern center fitting algorithm is available online.
准确确定花样中心一直是电子背散射衍射（EBSD）领域的一个挑战，对于最近出现的先进 EBSD 技术来说，其准确性已成为关键的限制因素。在这里，我们研究了花样中心必须被定量拟合的参数范围，并揭示其具有“宽松”和“嘈杂”的特点，这限制了花样中心可以被确定的准确性。为了在这个具有挑战性的环境中找到全局最优解，我们提出了两种方法的结合：使用全局搜索算法和对多个花样的结果进行平均。我们证明了能够准确确定模拟花样的花样中心，包括分箱和噪声对拟合花样中心误差的影响。我们还证明了该方法能够准确检测具有噪声和高度分箱的花样的花样中心的变化的能力。我们的花样中心拟合算法的源代码可在线获得。
