The dictionary approach for spherical deconvolution

  • Authors:
  • Thanh Mai Pham Ngoc;Vincent Rivoirard

  • Affiliations:
  • Laboratoire de Mathématique, UMR CNRS 8628, Université Paris Sud, 91405 Orsay Cedex, France;CEREMADE UMR CNRS 7534, Université Paris Dauphine, Place du Maréchal De Lattre De Tassigny, 75775 PARIS Cedex 16, France

  • Venue:
  • Journal of Multivariate Analysis
  • Year:
  • 2013

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Abstract

We consider the problem of estimating a density of probability from indirect data in the spherical convolution model. We aim at building an estimate of the unknown density as a linear combination of functions of an overcomplete dictionary. The procedure is devised through a well-calibrated @?"1-penalized criterion. The spherical deconvolution setting has been barely studied so far, and the two main approaches to this problem, namely the SVD and the hard thresholding ones considered only one basis at a time. The dictionary approach allows to combine various bases and thus enhances estimates sparsity. We provide an oracle inequality under global coherence assumptions. Moreover, the calibrated procedure that we put forward gives quite satisfying results in the numerical study when compared with other procedures.