Swiss Institute of Bioinformatics & Biozentrum, University of Basel, Klingelbergstrasse 50/70, Basel, Switzerland.
J Struct Biol. 2011 May;174(2):259-68. doi: 10.1016/j.jsb.2011.02.008. Epub 2011 Mar 23.
The phase contrast theory describes the transfer of information from a weak-phase object to the image plane of a transmission electron microscope. For a tilted sample where the distance from the focal plane varies continuously across the field of view, the recently introduced Tilted Contrast Imaging Function (TCIF) model provides the mathematical description of this information transfer. Here we expand the TCIF model to account for astigmatism, and present several methods to generate simulated images of tilted samples and compare them to experimental results. We analyze in depth the differences between TCIF and the classical Contrast Transfer Function (CTF) model, which assumes invariant defocus, and discuss how they can affect the interpretation of experimental data. In addition, we apply the TCIF model to simulated test objects in order to explore the performance of techniques that aim to correct the artifacts introduced by the imaging function, and evaluate how well they recover the original information after optimizing the parameters.
相衬理论描述了从弱相位物体向透射电子显微镜的像平面传递信息的过程。对于倾斜样品，从焦平面到视场的距离在整个视场中连续变化，最近引入的倾斜对比度成像函数（TCIF）模型提供了这种信息传递的数学描述。在这里，我们扩展了 TCIF 模型以考虑像散，并提出了几种生成倾斜样品模拟图像的方法，并将其与实验结果进行比较。我们深入分析了 TCIF 与经典对比度传递函数（CTF）模型之间的差异，后者假设不变的散焦，并讨论了它们如何影响对实验数据的解释。此外，我们将 TCIF 模型应用于模拟测试对象，以探索旨在纠正成像函数引入的伪影的技术的性能，并评估在优化参数后它们恢复原始信息的程度。
