Fourier shell correlation threshold criteria
Fourier shell correlation threshold criteria
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DOI：
10.1016/j.jsb.2005.05.009
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发表时间：
2005-09-01
影响因子：
3
通讯作者：
Schatz, M
中科院分区：
文献类型：
--
作者：
van Heel, M;Schatz, M
电子显微镜三维重建所要求的分辨率值表明了实验的整体质量。傅立叶壳相关（FSC）准则现在已经成为标准的质量度量。然而，一直存在争议的是FSC阈值水平的问题，在该阈值水平上定义了可再现的分辨率。在这里，我们讨论的FSC的理论行为结合影响它的各种因素：在一个给定的傅立叶壳的“体素”的数量，结构的对称性，以及重建体积内的结构的大小。理论上的考虑和我们的模型实验表明，固定值的FSC阈值（如“0.5”）可能永远不会被用于可重复的标准。正如我们在这里所展示的，固定的阈值仅仅是基本统计中错误假设的结果。讨论了两类FSC阈值曲线：σ因子曲线和新的基于比特的信息阈值曲线。sigma-factor曲线表示收集到的信息明显高于噪声水平的分辨率水平，而信息曲线表示收集到的信息足以进行解释的分辨率水平。(C)2005年爱思唯尔公司All rights reserved.
The resolution value claimed for an electron microscopical three-dimensional reconstruction indicates the overall quality of the experiment. The Fourier shell correlation (FSC) criterion has now become the standard quality measure. However, what has continued to be controversial is the issue of the FSC threshold level at which one defines the reproducible resolution. Here, we discuss the theoretical behaviour of the FSC in conjunction with the various factors which influence it: the number of "voxels" in a given Fourier shell, the symmetry of the structure, and the size of the structure within the reconstruction volume. Both the theoretical considerations and our model experiments show that fixed-valued FSC threshold (like "0.5") may never be used in a reproducible criterion. Fixed threshold values are-as we show here-simply the result of incorrect assumptions in the basic statistics. Two families of FSC threshold curves are discussed: the sigma-factor curves and the new family of bit-based information threshold curves. Whereas sigma-factor curves indicate the resolution level at which one has collected information significantly above the noise level, the information curves indicate the resolution level at which enough information has been collected for interpretation. (C) 2005 Elsevier Inc. All rights reserved.