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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.
  • Abrial P, Moudden Y, J.-L Starck, Fadili J, Delabrouille J, Nguyen M K
  • 2008
The statistical analysis of the soon to come Planck satellite CMB data will help set tighter bounds on major cosmological parameters. On the way, a number of practical difficulties need to be tackled, notably that several other astrophysical sources emit radiation in the frequency range of CMB observations. Some level of residual contributions, most(More)
In the last decade, the study of cosmic microwave background (CMB) data has become one of the most powerful tools to study and understand the Universe. More precisely, measuring the CMB power spectrum leads to the estimation of most cosmological parameters. Nevertheless, accessing such precious physical information requires extracting several different(More)
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)
Based on Cosmic Microwave Background (CMB) maps from the 2013 Planck Mission data release, this paper presents the detection of the Integrated Sachs-Wolfe (ISW) effect, i.e., the correlation between the CMB and large-scale evolving gravitational potentials. The significance of detection ranges from 2 to 4 σ, depending on which method is used. We investigate(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)
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)
We describe the use of the wavelet transform for multivariate data analysis problems. In prediction, a multiscale transform of time-varying data can allow forecasts of each scale, followed by combining of the individual forecasts. The use of a wavelet transform with noise modeling for point pattern clustering can lead to the result, which initially appears(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)