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: In this article, the mean speckle contrast at the center of the diffraction field of phase diffusers illuminated by a Gaussian beam focused by a lens which introduces primary spherical aberration was studied.
4 citations
TL;DR: In this paper , the integrated differential phase contrast (IDPC) method is used for generating the potential map of a thin sample and the authors evaluate theoretically the potential of IDPC imaging for thick samples by varying the focus at different sample thicknesses.
Abstract: The integrated differential phase contrast (IDPC) method is useful for generating the potential map of a thin sample. We evaluate theoretically the potential of IDPC imaging for thick samples by varying the focus at different sample thicknesses. Our calculations show that high defocus values result in enhanced anisotropy of the contrast transfer function (CTF) and uninterpretable images, if a quadrant detector is applied. We further show that applying a multi-sector detector can result in an almost isotropic CTF. By sector number-dependent calculations for both Cc/C3-corrected and C3-corrected scanning transmission electron microscopy (STEM), we show that the increase of detector sectors not only removes the anisotropy of the CTF, but also improves image contrast and resolution. For a proof-of-principle IDPC-STEM (uncorrected) experiment, we realize the functionality of a 12-sector detector from a physical quadrant detector and demonstrate the improvement in contrast and resolution on the example of InGaN/GaN quantum well structure.
4 citations
Patent•
25 Sep 2001
TL;DR: In this article, a phase plate placed on the rear focus surface of an object lens was used to obtain a differential contrast image obtained by phase manipulation with an odd contrast transfer function.
Abstract: PROBLEM TO BE SOLVED: To enable observation of electron microscope images by using phase contrast technique. SOLUTION: By phase manipulation with a phase plate placed on the rear focus surface of an object lens, a contrast transfer function is made an odd function, so as to obtain a differential contrast image obtained.
4 citations
IBM1
TL;DR: A real-time method for optimizing the defocus of a conventional transmission electron microscope in the phase contrast imaging mode has been investigated using image histogram data, which has distinct advantages of speed and minimal computational requirements over obtaining the power spectrum of an image.
Abstract: A real-time method for optimizing the defocus of a conventional transmission electron microscope in the phase contrast imaging mode has been investigated using image histogram data. This method can also be used to minimize the objective lens astigmatism. It will be shown both theoretically and empirically, using a digital television frame store, that a histogram will give the largest peak when an image has a broad and flat contrast transfer function. This method has distinct advantages of speed and minimal computational requirements over obtaining the power spectrum of an image.
4 citations
26 Jul 2011
4 citations