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SPIE Astronomical Telescopes and Instrumentation, Amsterdam : Pays-Bas (2012)
Multi-wavelength imaging algorithm for optical interferometry
Éric Thiébaut ( ) 1, Ferréol Soulez 2
ANR POLCA Collaboration(s)
(01/07/2012)

Optical interferometers provide multiple wavelength measurements. In order to fully exploit the spectral and spatial resolution of these instruments, new algorithms for image reconstruction have to be developed. Early attempts to deal with multi-chromatic interferometric data have consisted in recovering a gray image of the object or independent monochromatic images in some spectral bandwidths. The main challenge is now to recover the full 3-D (spatio-spectral) brightness distribution of the astronomical target given all the available data. We describe a new approach to implement multi-wavelength image reconstruction in the case where the observed scene is a collection of point-like sources. We show the gain in image quality (both spatially and spectrally) achieved by globally taking into account all the data instead of dealing with independent spectral slices. This is achieved thanks to a regularization which favors spatially sparsity and spectral grouping of the sources. Since the objective function is not differentiable, we had to develop a specialized optimization algorithm which also takes into account the non-negativity of the brightness distribution.
1 :  Centre de Recherche Astrophysique de Lyon (CRAL)
CNRS : UMR5574 – INSU – Université Claude Bernard - Lyon I – École Normale Supérieure (ENS) - Lyon
2 :  Centre Commun de Quantimétrie
Université Claude Bernard - Lyon I
AiRi
Informatique/Traitement du signal et de l'image

Sciences de l'ingénieur/Traitement du signal et de l'image

Planète et Univers/Astrophysique/Instrumentation et méthodes pour l'astrophysique

Physique/Astrophysique/Instrumentation et méthodes pour l'astrophysique
optical interferometry – image reconstruction – inverse problem – sparsity
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Thiebaut_Soulez-2012-Amsterdam.pdf(512.5 KB)
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Thiebaut_Soulez-2012-Amsterdam_slides.pdf(867.3 KB)