Correction for non-perpendicularity of beam and tilt axis in tomographic reconstructions with the IMOD package
Correction for non-perpendicularity of beam and tilt axis in tomographic reconstructions with the IMOD package
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DOI：
10.1111/j.1365-2818.2008.01977.x
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发表时间：
2008-05-01
影响因子：
2
通讯作者：
Mastronarde, D. N.
中科院分区：
文献类型：
--
作者：
Mastronarde, D. N.
在IMOD软件包中实现了电子层析倾斜系列中束轴与倾斜轴非平行性的校正，并探讨了其应用价值和局限性。在某些情况下，对这种效应的校正可以提供对准误差和重建质量的显著改善。然而，当投影模型拟合包括各向异性收缩（即拉伸）在平面上的标本，增加一个变量的光束倾斜不会产生较低的对准误差;因此，它是不可能区分拉伸和光束倾斜的影响。测试重建表明，包括拉伸的对准解决方案将充分校正光束倾斜的影响。对于在光束下发生变形的样本，考虑拉伸的对齐解决方案比考虑光束倾斜的对齐解决方案更可取，前提是用于对齐的标记足够均匀分布。否则，应使用波束倾斜校正。
A correction for non-perpendicularity between the beam axis and the tilt axis in electron tomographic tilt series has been implemented in the IMOD software package and its value and limitations have been explored. Correction for this effect can provide a significant improvement in the alignment error and the reconstruction quality in some cases. However, when the projection model being fit includes an anisotropic shrinkage (i.e. stretch) in the plane of the specimen, adding a variable for the beam tilt does not produce a lower alignment error; it is thus not possible to distinguish between the effects of stretch and beam tilt. Test reconstructions indicate that an alignment solution that includes stretch will adequately correct for the effects of a beam tilt. For specimens subject to deformation under the beam, an alignment solution that accounts for stretch is preferable to one that accounts for beam tilt instead, provided that the markers used for alignment are sufficiently well distributed. Otherwise, a correction for beam tilt should be used.