Foreword

Abstract
This book reports the proceedings of the third Journées d'Imagerie à Très Haute Dynamique et Détection d'Exoplanètes (Days on High Contrast Imaging and Exoplanets Detection) that were held in Nice and Fréjus in May, 16th-19th, 2005, with the joint efforts of the CNRS (Centre National de la Recherche Scientifique), the Observatoire de la Côte d'Azur, the Collège de France, and the Laboratoire Universitaire d'Astrophysique de Nice of the University of Nice Sophia-Antipolis.

The first and second Journées led to the publications of Volumes 8 and 12 of EAS Publications Series sharing the common title "Astronomy with High Contrast Imaging". Volume 8, subtitled "From Planetary Systems to Active Galactic Nuclei" collected 33 papers covering the very large domain of applications of High Contrast Imaging, from protoplanetary disks to AGNs. Volume 12, subtitled "Instrumentation for Coronagraphy and Nulling Interferometry" collected 29 papers dealing with technical aspects of the various experiments (apodisation, coronagraphy, nulling) that can lead to exoplanetographs, i.e. instruments able to directly record the light coming from planets orbitings stars other than the Sun. The present edition, third of these series on High Contrast Imaging, focuses on the aspects of image processing related to coronagraphy and nulling.

Technologies in competition are numerous, either from the point-of-view of the methods (coronagraphy, nulling, traditional interferometry, interferometry with densified pupils, etc.), the spectral domain (observations from the visible to 10 m), or the instrumentation (ground-based with the support of adaptive optics vs. space-born).

Which techniques and instruments are the most efficient for a given astronomical objective? The answer to this question must definitely also take into account the data processing retained for each instrument and a precise analysis of the related signal-to-noise ratio.

This school gathered basic lessons on optics, instrumentation and statistical data processing. The objective was to propose reliable tools of comparison of the various techniques.

The topic of the third Journées took the form of a multi-field CNRS Thematic School for the communities of astronomers and researchers from the domain of signal processing. The principal goal was to give to these communities the sufficient bases to communicate usefully between them. The book reports 22 courses and short presentations. It is organized in four sections: (i) modeling and data processing, (ii) adaptive optics, (iii) coronagraphy, and (iv) interferometry.