Volume 531, July 2011
|Number of page(s)||8|
|Section||Cosmology (including clusters of galaxies)|
|Published online||01 July 2011|
On the effect of image denoising on galaxy shape measurements
Laboratoire d’astrophysique, École Polytechnique Fédérale de Lausanne
(EPFL), Observatoire de Sauverny,
Received: 21 January 2011
Accepted: 24 April 2011
Weak gravitational lensing is a very sensitive way of measuring cosmological parameters, including dark energy, and of testing current theories of gravitation. In practice, this requires exquisite measurement of the shapes of billions of galaxies over large areas of the sky, as may be obtained with the EUCLID and WFIRST satellites. For a given survey depth, applying image denoising to the data both improves the accuracy of the shape measurements and increases the number density of galaxies with a measurable shape. We perform simple tests of three different denoising techniques, using synthetic data. We propose a new and simple denoising method, based on wavelet decomposition of the data and a Wiener filtering of the resulting wavelet coefficients. When applied to the GREAT08 challenge dataset, this technique allows us to improve the quality factor of the measurement (Q; GREAT08 definition), by up to a factor of two. We demonstrate that the typical pixel size of the EUCLID optical channel will allow us to use image denoising.
Key words: methods: data analysis / techniques: image processing / gravitational lensing: weak / dark energy / cosmological parameters / methods: statistical
© ESO, 2011
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.