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 article, the point spread function (PSF) and contrast transfer function (CTF) were measured using a fluorescent scale together with a fluorescent bead, and it was found that visible light can resolve a 100 nm line-and-space pattern by microcopy, and provide a contrast of 10%.
Abstract: We quantitatively investigated image properties in super-resolution microscopy using two-color fluorescence dip
spectroscopy. To evaluate the properties, the point spread function (PSF) and contrast transfer function (CTF) were
measured using a fluorescent scale together with a fluorescent bead. From the CTF, it has been found that visible light
can resolve a 100 nm line-and-space pattern by microcopy, and provide a contrast of 10%. The CTF corresponds to a
PSF with a FWHM of 130 nm. The value is two times finer than the diffraction limit size. An evaluation using a 100 nm
Φ fluorescent bead consistently supports the result given by the CTF for super-resolution microscopy. The measured
CTF shows that super-resolution microscopy can indeed improve the optical properties of fluorescent images and enable
us to observe a structure with a spatial resolution overcoming the diffraction limit.
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31 Jan 2006
TL;DR: In this paper, a primary spherical aberration phase factor is introduced for the spherical refracting system and the diffraction integral of the system is obtained, and the relation between fractional Fourier transform and the source of the aberration of imaging system is discussed.
Abstract: A primary spherical aberration phase factor is introduced for the spherical refracting system and the diffraction integral of the system is obtained. By omitting this primary spherical aberration phase factor, a specific crude imaging system is designed by cascading single spherical refracting fractional Fourier transform units. The spherical aberration of the system are numerically investigated. The relation between fractional Fourier transform and source of spherical aberration of imaging system is discussed.
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16 Sep 2011TL;DR: In this article, a method to characterize the optical performance of a high-resolution transmission x-ray microscope is presented, which makes use of test patterns that consist of random arrays of sub-resolution holes in a thin metal film, and so approximate to white noise input signals for the microscope.
Abstract: A novel method to characterize the optical performance of a high‐resolution transmission x‐ray microscope is presented. It makes use of test patterns that consist of random arrays of sub‐resolution holes in a thin metal film, and so approximate to white‐noise input signals for the microscope. The test patterns have been fabricated by electron‐beam lithography at length scales appropriate for the resolution available in x‐ray microscopy, so that diffractograms produced from the image data can be directly interpreted in terms of the contrast transfer function of the optical system. Results of this method are shown for both brightfield and differential phase contrast imaging.
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04 Mar 2015TL;DR: In this paper, the authors investigated the effect of the optical aperture on the aberration of liquid lenses based on electro-wetting and showed that the absolute value of positive and negative spherical aberration at the aperture of 4mm goes down by 2μm when the aperture goes up from 4.2mm to 5mm.
Abstract: For the liquid lens based on electro-wetting, the optical aperture influences the profile of the liquid drop due to the capillary effect, therefore, it will has an effect on the aberration of liquid lens. The spherical aberration caused by the different optical apertures with the different slope has been investigated by ray tracing. The analysis results have shown that the absolute value of positive and negative spherical aberration at the aperture of 4mm goes down by 2μm when the optical aperture goes up from 4.2mm to 5mm and that gradient of positive spherical aberration decrease with increasing optical aperture, that gradient of negative spherical aberration increase with increasing optical aperture. The critical turning voltage when spherical aberration changes from positive to negative is independent of optical aperture.