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: In this paper, a projection phase contrast microscopy experiment using hard x-ray pink beam undulator radiation focused by an adaptive mirror system to 100-200 nm spot size is reported.
Abstract: We report a projection phase contrast microscopy experiment using hard x-ray pink beam undulator radiation focused by an adaptive mirror system to 100--200 nm spot size. This source is used to illuminate a lithographic test pattern with a well-controlled range of spatial frequencies. The oscillatory nature of the contrast transfer function with source-to-sample distance in this holographic imaging scheme is quantified and the validity of the weak phase object approximation is confirmed for the experimental conditions.
16 citations
22 Feb 2006
TL;DR: In this article, a next generation scanning transmission electron microscope (STEM) fitted with a new design of aberration corrector is shown to have improved spatial resolution and beam convergence with a convergence semi-angle of 40 mrad.
Abstract: Through the correction of spherical aberration in the scanning transmission electron microscope (STEM), the resolving of a 78 pm atomic column spacing has been demonstrated along with information transfer to 61 pm. The achievement of this resolution required careful control of microscope instabilities, parasitic aberrations and the compensation of uncorrected, higher order aberrations. Many of these issues are improved in a next generation STEM fitted with a new design of aberration corrector, and an initial result demonstrating aberration correction to a convergence semi-angle of 40 mrad is shown. The improved spatial resolution and beam convergence allowed for by such correction has implications for the way in which experiments are performed and how STEM data should be interpreted.
16 citations
TL;DR: The scanning transmission electron microscope (STEM) offers several advantages in studying a molecule such as fibrinogen, including: Lack of phase contrast when using the large angle annular detector makes image intensity directly interpretable in terms of mass thickness.
Abstract: The scanning transmission electron microscope (STEM) offers several advantages in studying a molecule such as fibrinogen. Molecules and their domains observed unstained in dark field can be identified directly by their mass. Thus, it is possible to correlate the STEM image directly with biochemical models. Lack of phase contrast when using the large angle annular detector makes image intensity directly interpretable in terms of mass thickness (no oscillations in the contrast transfer function). Certain specimen preparation artifacts such as denatured protein films are detected easily in the STEM and can be avoided through suitable specimen preparation techniques. 50 references.
15 citations
TL;DR: A formal definition of contrast sensitivity that can be applied to individual linear visual neurons is derived and may be used to relate the sensitivities of various populations of neurons, and to relate to that of the behaving animal.
Abstract: Contrast sensitivity is a measure of the ability of an observer to detect contrast signals of particular spatial and temporal frequencies. A formal definition of contrast sensitivity that can be applied to individual linear visual neurons is derived. A neuron is modeled by a contrast transfer function and its modulus, contrast gain, and by a noise power spectrum. The distributions of neural responses to signal and blank presentations are derived, and from these, a definition of contrast sensitivity is obtained. This formal definition may be used to relate the sensitivities of various populations of neurons, and to relate the sensitivities of neurons to that of the behaving animal.
15 citations
Patent•
30 Oct 2006
TL;DR: In this paper, an automatic aberration correction using a Ronchigram automatically in a correction method and a device using ronchigrams was proposed. But the method was not suitable for the case where the electron microscope has a function of displaying an image by focusing electron beams (probe) on a test piece, and scanning the electron beams on the test piece.
Abstract: PROBLEM TO BE SOLVED: To carry out aberration correction using a Ronchigram automatically in a aberration correction method and a device using the ronchigram. SOLUTION: The electron microscope has a function of displaying an image by focusing electron beams (probe) on a test piece, scanning the electron beams on the test piece, and interlocking the detected signal of electrons transmitted through the test piece with the electron beam scanning, and comprises a first calculation means to obtain an auto-correlation in micro-regions of a Ronchigram of an amorphous test piece, a detection means to detect aberration of electron beams formed of local angle regions on an open face from the auto-correlation or an Fourier analysis of the auto-correlation, a second calculation means to calculate each aberration based on the detection result, and a control means to control aberration correction operation based on the calculation result of the calculation means. By this structure, aberration correction using Ronchigram can be carried out automatically. COPYRIGHT: (C)2007,JPO&INPIT
15 citations