Disciplines
Computer Sciences (5%); Mathematics (95%)
Keywords
Inverse Problems,
Regularization,
Bregman distance,
Csiszar divergence,
Mirror Descent Method,
Proximal Point Method
Abstract
Inverse problems constitute an essential framework for approaching a large variety of issues in
technical and medical domains. However, most inverse problems are ill-posed, meaning that small
perturbations in the data can trigger high oscillations in the solution. Thus, rapid developments in the
above-mentioned domains make designing efficient and stable inverse problems algorithms a
continuous challenge. A promising direction in this respect is to investigate methods using more
sophisticated measures for distances between points, rather than the Euclidean-type distances. In
this project, we aim at efficiently recovering stable approximations of inverse problems solutions with
certain features, such as nonnegativity, sparsity, and piecewise constant structure. The main novelty
here is solving such problems by iterative methods that exploit the versatile role of distance-like
functions in promoting the solution features and accelerating the convergence of the iterates. The
infinite dimensional setting that naturally anchors these problems brings even more complexity to
the envisaged framework. We would like to propose and analyze accelerated versions of several
iterative methods based on such distance-like functions, both theoretically and computationally, and
to compare them with well-established methods. Interesting links to machine learning and image
processing can also be investigated.
- Alfredo Noel Iusem, Fundacao Getulio Vargas - Brazil
- Pierre Marechal, Université Paul Sabatier de Toulouse - France
- Martin Benning, Universal College London