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, a three-dimensional reconstruction of nano-scale objects (such as biological macromolecules) can be accomplished using data recorded with a transmission electron microscope using Chahine's method.
Abstract: Three-dimensional reconstruction of nano-scale objects (such as biological macromolecules) can be accomplished using data recorded with a transmission electron microscope An image obtained by a transmission electron microscope can be conceived of as an 'ideal' projection subjected to a contrast transfer function, which attenuates most frequencies, reverses the phase of others and even eliminates some of them Such instrumental aberrations make the problem of reconstruction from such data difficult We reformulate the problem so that Chahine's method becomes applicable to it We demonstrate the performance of our approach with numerical evidence using both simulated and actual electron microscopy data
22 citations
TL;DR: In this paper, it was shown that the focal shift of a Gaussian laser beam can be offset with the use of the spherical aberration of a focusing lens, which is applicable to a low Fresnel number focusing system.
22 citations
TL;DR: An auto-tuning method for high-angle annular detector dark field scanning transmission electron microscopy (HAADF-STEM) is proposed which corrects the defocus to the optimum Scherzer focus and compensates the astigmatism.
Abstract: An auto-tuning method for high-angle annular detector dark field scanning transmission electron microscopy (HAADF-STEM) is proposed which corrects the defocus to the optimum Scherzer focus and compensates the astigmatism. Because the method is based on the image contrast transfer function formulated for the HAADF-STEM, the defocus and the astigmatism are accurately measured from input of two different defocus images. The method is designed to work independent of object function in the linear imaging model by analysing the spectral ratio between two Fourier spectra of their images, which is useful for cases where the spectrum of object function is not uniformly spread out over the reciprocal space. The method was preliminarily tested in a Hitachi HD-2000 STEM, and successful results of the auto-tunings from the viewpoint of verification of the algorithm were obtained using general specimens of Au fine particles and a thin section of a semiconductor device.
22 citations
TL;DR: In this article, the relation between wave optics and geometrical optics has been studied generally by using the Fourier analysis and the general theory is applied to the concrete examples of the astigmatism, coma, and spherical aberration, and the following results are obtained.
Abstract: In the previous paper (part I), the relation between wave optics and geometrical optics has been studied generally by using the Fourier analysis. In this paper the general theory is applied to the concrete examples of the astigmatism, coma, and spherical aberration, and the following results are obtained.In case of astigmatism, if the magnitude of the wave aberration |ωλ| is larger than 2λ (λ being the wavelength), the geometric optical response function Rg(s) approximates to the wave optical response function Rw(s) within the region of the normalized frequency s where |λs/2| 1.2λ and |λs/2| 1.6λ and |λt/2| 1.3λ and |λs/2|<0.4.
22 citations
TL;DR: In this paper, the validity of weak-phase object approximation in amorphous thin films is resolution dependent, and the appearance of diffractograms from far out-of-focus to measure the information-limit resolution, and other optical parameters.
22 citations