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.
Papers published on a yearly basis
Papers
More filters
TL;DR: It is shown that compensation for the contrast transfer function is necessary and sufficient to convert the images into accurate representations of molecular density and in quantitative agreement with the atomic model derived from X-ray results.
112 citations
TL;DR: This work presents an alternative and successful method to eliminate the chromatic blur, which consists of monochromating the TEM beam and shows directly interpretable resolutions well below 1A for the first time, which is significantly better than any TEM operating at 200 KV has reached before.
112 citations
TL;DR: In this article, the scalar three-dimensional optical transfer function without using the paraxial approximation was derived for a partially coherent system with equal condenser and objective apertures and the coherent transfer function for a confocal transmission system.
Abstract: The scalar three-dimensional optical transfer function is derived without using the paraxial approximation. The weak-object transfer function for a partially coherent system with equal condenser and objective apertures and the coherent transfer function for a confocal transmission system are of identical form. The coherent transfer function of a confocal reflection system is also derived. Both uniform angular illumination and systems obeying the sine condition are considered. In all cases the transfer functions can be expressed analytically.
112 citations
TL;DR: It is shown that optimal resolution can be restored to a spherically aberrated image by constrained, iterative deconvolution, as long as the spherical aberration in the point spread function used for deconvolved image matches the aberrations in the image reasonably well.
Abstract: The wavelength dependence of the incoherent point spread function in a wide-field microscope was investigated experimentally. Dispersion in the sample and optics can lead to significant changes in the point spread function as wavelength is varied over the range commonly used in fluorescence microscopy. For a given sample, optical conditions can generally be optimized to produce a point spread function largely free of spherical aberration at a given wavelength. Unfortunately, deviations in wavelength from this value will result in spherically aberrated point spread functions. Therefore, when multiple fluorophores are used to localize different components in the same sample, the image of the distribution of at least one of the fluorophores will be spherically aberrated. This aberration causes a loss of intensity and resolution, thereby complicating the localization and analysis of multiple components in a multi-wavelength image. We show that optimal resolution can be restored to a spherically aberrated image by constrained, iterative deconvolution, as long as the spherical aberration in the point spread function used for deconvolution matches the aberration in the image reasonably well. The success of this method is essentially independent of the initial degree of spherical aberration in the image. Deconvolution of many biological images can be achieved by collecting a small library of spherically aberrated and unaberrated point spread functions, and then choosing a point spread function appropriate for deconvolving each image. The co-localization and relative intensities of multiple components can then be accurately studied in a multi-wavelength image.
108 citations
TL;DR: A forward model that accounts for the specimen's scattering properties, microscope optics, and detector response and suggests that beam-induced specimen movements are relevant in the experiments whereas the influence of the solvent amorphousness can be neglected.
108 citations