Dual-axis tomography: An approach with alignment methods that preserve resolution
Dual-axis tomography: An approach with alignment methods that preserve resolution
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DOI：
10.1006/jsbi.1997.3919
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发表时间：
1997-12-01
影响因子：
3
通讯作者：
Mastronarde, DN
中科院分区：
文献类型：
--
作者：
Mastronarde, DN
生物标本的层析成像重建，现在通常是在我们的高压电子显微镜产生的倾斜标本围绕两个正交轴。从每个倾斜系列计算单独的断层图像。这两个断层图像通过一般的3-D线性变换彼此对齐，该3-D线性变换可以校正两个断层图像之间的失真，从而在其整个体积中保持重建的固有分辨率。然后选择性地组合两个断层图像的3-D傅立叶变换以实现单个断层图像。与单轴断层图像不同，双轴断层图像在样本平面的任何方向上都显示出良好的扩展功能分辨率;它还提高了样本深度的分辨率。计算表明，从双倾斜和从倾斜到更高角度可获得的改进在很大程度上是相加的。实际和模型数据被用来评估是否改变倾斜视图之间的增量成比例的余弦的倾斜角将允许减少所需的图片的数量，以实现给定的重建分辨率。傅立叶扇形相关分析表明，可变倾斜增量在某些方面改善了重建，但在其他方面降低了重建。因此，变化的倾斜增量不会给出不合格的改进，至少在使用反投影算法进行重建时。(C)北京：科学出版社.
Tomographic reconstructions of biological specimens are now routinely being generated in our high voltage electron microscope by tilting the specimen around two orthogonal axes. Separate tomograms are computed from each tilt series. The two tomograms are aligned to each other with general 3-D linear transformations that can correct for distortions between the two tomograms, thus preserving the inherent resolution of the reconstruction throughout its volume. The 3-D Fourier transforms of the two tomograms are then selectively combined to achieve a single tomogram. Unlike a single-axis tomogram, a dual-axis tomogram shows good resolution for extended features at any orientation in the plane of the specimen; it also has improved resolution in the depth of the specimen. Calculations indicate that the improvements available from double tilting and from tilting to higher angles are largely additive. Actual and model data were used to assess whether varying the increment between tilted views in proportion to the cosine of the tilt angle would allow a reduction in the number of pictures required to achieve a given resolution of reconstruction. Analysis by Fourier sector correlation indicated that the variable tilt increment improved the reconstruction in some respects but degraded it in others. A varying tilt increment thus does not give an unqualified improvement, at least when using back-projection algorithms for the reconstruction. (C) 1997 Academic Press.