Optical Diffraction and Filtering and Three-Dimensional Reconstructions from Electron Micrographs
Optical Diffraction and Filtering and Three-Dimensional Reconstructions from Electron Micrographs
复制标题
光学衍射和过滤以及电子显微照片的三维重建
DOI：
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发表时间：
1971
期刊：
影响因子：
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通讯作者：
A. Klug
中科院分区：
文献类型：
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作者：
A. Klug
本节介绍近年来发展起来的一些处理电子显微照片中记录的信息的方法，以便人们能从这些照片中提取有关被检查的三维结构的最大可靠信息量。基本的问题是电子显微镜的焦深有几百纳米，这样所有沿观察方向沿着的特征都叠加在图像中。通过直接观察的感知是有限的，因为我们不习惯于看穿一个物体。因此，人们在图片中“看到”的细节是混乱的，如果没有将样本中不同层次对图像的贡献分开的方法，就不容易解释。这些方法在应用于周期性重复结构（无论是平移对称还是旋转对称）时特别强大，但在其最终形式中，这些方法可以处理一般的非对称粒子。这些方法与X射线晶体学家用来测量周期性或有序度并最终观察更简单物质中原子排列的方法非常相似。然而，不同的是，这里没有相位问题，因为相位信息包含在电子显微照片中。
This section deals with some methods which have been developed in recent years for processing the information recorded in electron micrographs so that one can extract from them the maximum amount of reliable information about the three-dimensional structures which are being examined. The basic problem is that the electron microscope has a depth of focus of several hundred nanometres, so that all features along the direction of view are superimposed in the image. There is a limit to perception by direct inspection because we are not accustomed to seeing through an object. The details one ‘sees’ in a picture are therefore confused and not easily interpretable without methods which separate the contributions to the image from different levels in a specimen. The methods are particularly powerful when applied to periodically repeating structures (whether with translational or rotational symmetry), but in their ultimate form the methods can deal with the general asymmetric particle. The methods are closely analagous to those used by X-ray crystallographers to measure periodicities or degrees of order and finally to see the arrangement of atoms in simpler substances. The difference, however, is that there is no phase problem here because the phase information is contained in the electron micrograph.