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Reconstruction d'images astronomiques en interférométrie optique

Abstract : The resolution of a telescope is limited by its diameter. Optical interferometry allows to reach the resolution of a ``large'' telescope by coupling several smaller ones. Interferometry imaging has first developed in radio-astronomy, for which efficient data processing techniques can be used. However, they do not apply directly to optical interferometric data, for which the phase information is corrupted by the atmospheric turbulence. The only available phase data are the closure phases.

In this PhD, we have tried to design an image reconstruction method suited to optical interferometry, and to validate it on experimental data. We have
proposed the algorithm WISARD, which combines, within a Bayesian framework, a myopic description of the turbulence effects, an alternating estimation of the object and phase parameters (in the spirit of self-calibration algorithms proposed by radio-astronomers), a recently developed noise model suited to optical interferometry data and an accurate regularization to deal with the sparsity of the data typical of optical interferometry.

Our method has been validated on simulations and successfully compared to other methods during an international image reconstruction blind contest. From the data we have collected on the IOTA interferometer, we have been able to reconstruct with WISARD an image of the star Chi Cygni.
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Contributor : Serge Meimon <>
Submitted on : Wednesday, January 11, 2006 - 6:42:21 PM
Last modification on : Tuesday, March 16, 2021 - 3:42:04 PM
Long-term archiving on: : Saturday, April 3, 2010 - 9:13:00 PM

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Serge Meimon. Reconstruction d'images astronomiques en interférométrie optique. Astrophysique [astro-ph]. Université Paris Sud - Paris XI, 2005. Français. ⟨tel-00011355⟩

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