Spatial filters of function and phylogeny determine morphological disparity with latitude

The coherence of the electron flux of a transmission electron microscope (TEM) limits the direct application of deconvolution techniques which have been used successfully on unmanned spacecraft programs. The theory assumes noncoherent illumination. Deconvolution of a TEM micrograph will, therefore, in general produce spurious detail rather than improved resolution.A primary goal of our research is to study the performance of several types of linear spatial filters as a function of specimen contrast, phase, and coherence. We have, therefore, developed a one-dimensional analysis and plotting program to simulate a wide 'range of operating conditions of the TEM, including adjustment of the:(1) Specimen amplitude, phase, and separation(2) Illumination wavelength, half-angle, and tilt(3) Objective lens focal length and aperture width(4) Spherical aberration, defocus, and chromatic aberration focus shift(5) Detector gamma, additive, and multiplicative noise constants(6) Type of spatial filter: linear cosine, linear sine, or deterministic

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A light optical diffractometer for electron microscopical images operating in line

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100107575 ◽

1978 ◽

Vol 36 (1) ◽

pp. 86-87

Author(s):

P. Bonhomme ◽

A. Beorchia

Keyword(s):

Electron Microscopy ◽

Electron Transfer ◽

Electron Microscope ◽

Image Converter ◽

Coherent Light ◽

Spatial Filters ◽

Electron Image ◽

Electron Microscopical ◽

Working Parameters ◽

Amorphous Part

We have already described (1.2.3) a device using a pockel's effect light valve as a microscopical electron image converter. This converter can be read out with incoherent or coherent light. In the last case we can set in line with the converter an optical diffractometer. Now, electron microscopy developments have pointed out different advantages of diffractometry. Indeed diffractogram of an image of a thin amorphous part of a specimen gives information about electron transfer function and a single look at a diffractogram informs on focus, drift, residual astigmatism, and after standardizing, on periods resolved (4.5.6). These informations are obvious from diffractogram but are usualy obtained from a micrograph, so that a correction of electron microscope parameters cannot be realized before recording the micrograph. Diffractometer allows also processing of images by setting spatial filters in diffractogram plane (7) or by reconstruction of Fraunhofer image (8). Using Electrotitus read out with coherent light and fitted to a diffractometer; all these possibilities may be realized in pseudoreal time, so that working parameters may be optimally adjusted before recording a micrograph or before processing an image.

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Segmentation of SAR Image using Fuzzy C-Means and Filters

Science & Technology Journal ◽

10.22232/stj.2020.08.01.11 ◽

2020 ◽

Vol 8 (1) ◽

pp. 84-90

Author(s):

R. Lalchhanhima ◽

◽

Debdatta Kandar ◽

R. Chawngsangpuii ◽

Vanlalmuansangi Khenglawt ◽

...

Keyword(s):

Clustering Algorithm ◽

State Of The Art ◽

Speckle Noise ◽

Synthetic Aperture Radar Image ◽

Synthetic Aperture ◽

Sar Image ◽

Spatial Filters ◽

Fuzzy C Means ◽

Automatic Clustering ◽

Intensity Information

Fuzzy C-Means is an unsupervised clustering algorithm for the automatic clustering of data. Synthetic Aperture Radar Image Segmentation has been a challenging task because of the presence of speckle noise. Therefore the segmentation process can not directly rely on the intensity information alone but must consider several derived features in order to get satisfactory segmentation results. In this paper, it is attempted to use the fuzzy nature of classification for the purpose of unsupervised region segmentation in which FCM is employed. Different features are obtained by filtering of the image by using different spatial filters and are selected for segmentation criteria. The segmentation performance is determined by the accuracy compared with a different state of the art techniques proposed recently.

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