Iterative image reconstruction from the bispectrum of astronomical speckle interferograms

K.-H. Hofmann

doi:10.1117/12.2308499

26 July 1993 Iterative image reconstruction from the bispectrum of astronomical speckle interferograms

K.-H. Hofmann

Proceedings Volume 1983, 16th Congress of the International Commission for Optics: Optics as a Key to High Technology; 198328 (1993) https://doi.org/10.1117/12.2308499
Event: 16th Congress of the International Commission for Optics: Optics as a Key to High Technology, 1993, Budapest, Hungary

Abstract

The atmosphere of the earth restricts the angular resolution of large, ground-based telescopes to about 0.5 arc- sec. Atmospheric image degradation can be overcome by various interferometric speckle techniques. Bispectrum analysis 1,2 (also called speckle masking) of many speckle interferograms (short-exposure photographs; exposure time 0.05 sec) yields diffraction-limited images with, for example, 0.02 arcsec resolution for a 5 m telescope. After the first processing steps of speckle masking the object bispectrum 0(3)(u, v) is obtained up to the cut-off frequency of the telescope. From the object bispectrum a diffraction-limited image can be derived by (a) the conventional recursive method 2 (the object Fourier phase is extracted recursively from 0(3)(u, v)) or (b) iterative least-squares methods. The iterative building block method3-7 discussed below is an extension of the gridfit method8 used in radio interferometry. This algorithm searches for that high-resolution image which has the best agreement with the measured object bispectrum.

Citation Download Citation

K.-H. Hofmann "Iterative image reconstruction from the bispectrum of astronomical speckle interferograms", Proc. SPIE 1983, 16th Congress of the International Commission for Optics: Optics as a Key to High Technology, 198328 (26 July 1993); https://doi.org/10.1117/12.2308499

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available