J.-L Starck

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We describe image compression based on the pyramidal median transform, introduced as an alternative to the use of a wavelet transform. The use of a multiresolution support allows \protection" of astronomical objects in the image. Non-support parts of the images are subjected to noise suppression. Experimental applications are presented.
We present several wavelet transform algorithms and their applications in astronomical image processing (restoration, object detection , compression, etc.). Extensive literature exists on the wavelet transform and its application (Chui 1992; Daubechies 1992; Meyer 1989). A discrete wavelet transform approach can be obtained from multiresolution analysis(More)
Context. The Planck satellite will map the full sky at nine frequencies from 30 to 857 GHz. The CMB intensity and polarization that are its prime targets are contaminated by foreground emission. Aims. The goal of this paper is to compare proposed methods for separating CMB from foregrounds based on their different spectral and spatial characteristics, and(More)
The Open University's repository of research publications and other research outputs ¡i¿Planck¡/i¿ early results. XIII. Statistical properties of extragalactic radio sources in the ¡i¿Planck¡/i¿ Early Release Compact Source Catalogue Journal Article Copyright and Moral Rights for the articles on this site are retained by the individual authors and/or other(More)
The measurement of the root-mean-square (rms) acceleration of vibration does does not take into consideration the short high peak values of the vibratory signal, which may be a hazard contributing to the development of vibration-induced disease. A method for evaluating the impulse character of vibratory signals is given, and impulsiveness is defined as the(More)
Aims. We prepare real-life Cosmic Microwave Background (CMB) lensing extraction with the forthcoming Planck satellite data, by studying two systematic effects related to the foregrounds contamination: the impact of foreground residuals after a component separation on the lensed CMB map, and of removing a large contaminated region of the sky. Methods. We(More)
Using a set of ROSAT HRI deep pointings, we investigate the presence of small-scale structures in the central regions of clusters of galaxies. Our sample comprises 23 objects up to z = 0.32, 13 of them known to host a cooling flow. Structures are detected and characterized using a wavelet analysis , their statistical significance being assessed by a(More)
Estimating the cosmological microwave background is of utmost importance for cosmology. However, its estimation from full-sky surveys such as WMAP or more recently Planck is challenging : CMB maps are generally estimated via the application of some source separation techniques which never prevent the final map from being contaminated with noise and(More)
In this chapter we review a variety of 3D sparse representations developed in recent years and adapted to different kinds of 3D signals. In particular, we describe 3D wavelets, ridgelets, beamlets and curvelets. We also present very recent 3D sparse representations on the 3D ball adapted to 3D signal naturally observed in spherical coordinates. Illustrative(More)