Speckle Interferometry, Image Reconstruction By Speckle Masking, Speckle Spectroscopy, Multiple-Mirror Interferometry

1985 ◽  
Author(s):  
G. Weigelt ◽  
G. Baier ◽  
J. Ebersberger ◽  
F. Fleischmann ◽  
K.-H. Hofmann ◽  
...  
1984 ◽  
Vol 79 ◽  
pp. 309-336 ◽  
Author(s):  
A. Chelli

I-INTRODUCTION The speckle interferometry method has been introduced in 1970 by A. Labeyrie who showed in the visible dcmain that it was possible to reach the limiting spatial resolution of large telescopes. From 1977, the method is extended to the near infrared between 2 and 5ym (Lena, 1977; Wade and Selby, 1978) ,7 years later infrared speckle systems are operating on several large telescopes (ESO, KPNO, AAT, UKIRT, CFHT... ).The speckle interferometry method has allowed to better understanding the optical properties of the atmosphere, especially owing to the work of F.Roddier (Roddier, 1981). It has raised new problems like the phase restitution of the object spectrum and has largely contributed to the development of image reconstruction methods.


1990 ◽  
Author(s):  
Taylor W. Lawrence ◽  
J. Patrick Fitch ◽  
Dennis M. Goodman ◽  
Norbert A. Massie ◽  
Robert J. Sherwood

1979 ◽  
Vol 50 ◽  
pp. 33-1-33-12
Author(s):  
Gerd P. Weigelt

AbstractThe angular resolution of conventional astrophotography is limited to about 1 sec of arc due to image degradation by the atmosphere and telescope aberrations. Higher resolution can be achieved by Labeyrie's speckle interferometry, which yields the autocorrelation of astronomical objects with diffraction-limited resolution, e.g. 0.02 sec of arc with 5m telescope aperture.We have investigated modifications of speckle interferometry, which yield diffraction-limited images. We investigated (1) “speckle holography” for image reconstruction of objects near an unresolvable point source (reference star), (2) “speckle masking” for image reconstruction of binary stars (without a reference star), and (3) “phase flipping” for image reconstruction of centro-symmetric objects. Together these three image reconstruction methods represent a set of speckle evaluation procedures, which can yield high resolution images of most astronomical objects that are bright enough for speckle interferometry. Speckle holography was already applied to astronomical objects. We reconstructed real images of the binary star Zeta Cancri A-B and the triple star ADS 3358 A-B-C ( 0.07 sec of arc resolution with 1.8m telescope aperture).


1994 ◽  
Vol 158 ◽  
pp. 346-348
Author(s):  
P. Qiu ◽  
Y. Qiu ◽  
P. Qian ◽  
Z. Liu

The research on the high resolution image reconstruction has been carried out at the Yunnan Observatory, the Chinese Academy of Sciences, since 1983. At the early stage in 1983–1987, our research was concentrated on the Speckle Interferometry[1]. The first developed speckle camera for using the film as the recording medium was made up of an intensifier with a gain of 57,000 and an SB-408-B oscilloscope camera. In May, 1985, 144 speckle interferograms of the binary ζBoo and the unresolved single star 32 Boo apiece were obtained with the speckle camera attached to the 1-M Rcc telescope, and the average power spectrum of ζBoo was then acquired by means of the Optical Fourier Transformation[2]. Soon afterwords, the optical couple of the intensifier to a RCA CCD(320×512 pixels) through a lens was used to replace the film and the oscilloscope camera, thereby making an improvement on the detectability up to 7m from 4m. In December, 1986 the improved camera attached to 1-M telescope was used to observe three binary stars, i.e. Kui23, Σ73 and Σ346AB. The speckle interferograms were processed with a computer and angular seperations of these binaries were obtained approximate to the diffraction-limited resolution of the telescope[3].


Author(s):  
R. A. Crowther

The reconstruction of a three-dimensional image of a specimen from a set of electron micrographs reduces, under certain assumptions about the imaging process in the microscope, to the mathematical problem of reconstructing a density distribution from a set of its plane projections.In the absence of noise we can formulate a purely geometrical criterion, which, for a general object, fixes the resolution attainable from a given finite number of views in terms of the size of the object. For simplicity we take the ideal case of projections collected by a series of m equally spaced tilts about a single axis.


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