Topic
Contrast transfer function
About: Contrast transfer function is a research topic. Over the lifetime, 934 publications have been published within this topic receiving 26533 citations.
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TL;DR: The results of practical experiments are presented to verify that with illumination settings typically used in the electron microscopy of biological macromolecules, systematic variations in magnification of 0.5% per microm defocus can easily occur and highlight the need for a magnification-invariant imaging mode to eliminate or to compensate for this effect.
Abstract: It has previously been shown that - in theory - magnification variations can occur in an imaging system as a function of defocus, depending on the field curvature of the illuminating system. We here present the results of practical experiments to verify this effect in the transmission electron microscope. We find that with illumination settings typically used in the electron microscopy of biological macromolecules, systematic variations in magnification of ~ 0.5% per microm defocus can easily occur. This work highlights the need for a magnification-invariant imaging mode to eliminate or to compensate for this effect.
7 citations
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TL;DR: In this paper, the authors present theory and simulations showing that the maximum spatial frequency can be increased considerably almost without loss of contrast by using a Hilbert phase plate of half the thickness, leading to a phase shift of π 2 and recording images at Scherzer defocus.
6 citations
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TL;DR: It is found that lens aberrations, and spatial and temporal coherence may affect the validity of the CTF approach to model LEEM image formation under certain conditions, and the foundation for quantitative image evaluation using these methods is laid.
6 citations
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TL;DR: This paper derives and analyzes contrast transfer function results obtained with 1D as well as 2D templates.
Abstract: Present determination of optical imaging systems specifications are based on performance values and modulation transfer function results carried with a 1D resolution template (such as the USAF resolution target or spoke templates). Such a template allows determining image quality, resolution limit, and contrast. Nevertheless, the conventional 1D template does not provide satisfactory results, since most optical imaging systems handle 2D objects for which imaging system response may be different by virtue of some not readily observable spatial frequencies. In this paper we derive and analyze contrast transfer function results obtained with 1D as well as 2D templates.
6 citations
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01 Jan 1944TL;DR: A survey of the basic theory of electron microscopy is given in this article with special emphasis on the limitations of the resolving power of the resolution power of a transmission electron microscope, which is the most widely used electron microscope type.
Abstract: The optics of the most widely used type of electron microscope-the transmission type-is described. A survey of the basic theory is given with special emphasis on the limitations of the resolving power.
6 citations