Modeling truncated pixel values of faint reflections in MicroED images
Modeling truncated pixel values of faint reflections in MicroED images
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DOI：
10.1107/s1600576716007196
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发表时间：
2016-06-01
影响因子：
6.1
通讯作者：
Gonen, Tamir
中科院分区：
文献类型：
--
作者：
Hattne, Johan;Shi, Dan;Gonen, Tamir
衍射图像中布拉格斑点周围的弱像素数对于建立峰下背景模型和估计积分强度的可靠性是重要的。在某些情况下，特别是对于未针对低强度测量进行优化的设备，这些像素值可能会被应用于原始图像的校正所破坏。这可能导致低像素计数的截断，从而导致积分布拉格强度的异常，例如系统性较高的信噪比。这种效应的校正可以近似由三参数对数正态分布拟合到弱正值像素在类似的散射角。该程序是通过改进的细化原子模型对结构因子振幅来自校正的微电子衍射（MicroED）图像进行验证。
The weak pixel counts surrounding the Bragg spots in a diffraction image are important for establishing a model of the background underneath the peak and estimating the reliability of the integrated intensities. Under certain circumstances, particularly with equipment not optimized for low-intensity measurements, these pixel values may be corrupted by corrections applied to the raw image. This can lead to truncation of low pixel counts, resulting in anomalies in the integrated Bragg intensities, such as systematically higher signal-to-noise ratios. A correction for this effect can be approximated by a three-parameter lognormal distribution fitted to the weakly positive-valued pixels at similar scattering angles. The procedure is validated by the improved refinement of an atomic model against structure factor amplitudes derived from corrected micro-electron diffraction (MicroED) images.