Multidimensional Shrinkage-Thresholding Operator and Group LASSO Penalties

Autor: Arnau Tibau Puig, Ami Wiesel, Gilles Fleury, Alfred O. Hero
Přispěvatelé: Department of Electrical Engineering and Computer Science (EECS), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, School of Computer Science and Engineering (The Hebreu University of Jerusalem), The Hebreu University of Jerusalem, Supélec Sciences des Systèmes (E3S), Ecole Supérieure d'Electricité - SUPELEC (FRANCE)
Rok vydání: 2011
Předmět:
Zdroj: IEEE Signal Processing Letters
IEEE Signal Processing Letters, Institute of Electrical and Electronics Engineers, 2011, 18 (6), pp.363-366. ⟨10.1109/LSP.2011.2139204⟩
ISSN: 1558-2361
1070-9908
DOI: 10.1109/lsp.2011.2139204
Popis: The scalar shrinkage-thresholding operator is a key ingredient in variable selection algorithms arising in wavelet denoising, JPEG2000 image compression and predictive analysis of gene microarray data. In these applications, the decision to select a scalar variable is given as the solution to a scalar sparsity penalized quadratic optimization. In some other applications, one seeks to select multidimensional variables. In this work, we present a natural multidimensional extension of the scalar shrinkage thresholding operator. Similarly to the scalar case, the threshold is determined by the minimization of a convex quadratic form plus an Euclidean norm penalty, however, here the optimization is performed over a domain of dimension N ≥ 1. The solution to this convex optimization problem is called the multidimensional shrinkage threshold operator (MSTO). The MSTO reduces to the scalar case in the special case of N=1. In the general case of N >; 1 the optimal MSTO shrinkage can be found through a simple convex line search. We give an efficient algorithm for solving this line search and show that our method to evaluate the MSTO outperforms other state-of-the art optimization approaches. We present several illustrative applications of the MSTO in the context of Group LASSO penalized estimation.
Databáze: OpenAIRE