Minimax optimal level set estimation
Tree-structured partitions provide a natural framework for rapid and accurate extraction of level sets of a multivariate function f from noisy data. In general, a level set S is the set on which f exc...
Monochrome and color image denoising using neighboring dependency and data correlation
In this paper, two approaches for image denoising that take advantages of neighboring dependency in the wavelet domain are studied. The first approach is to take into account the higher order statisti...
Diffusion-driven multiscale analysis on manifolds and graphs: top-down and bottom-up constructions
Proc. SPIE, Vol. 5914, 59141D (2005);
doi:10.1117/12.616931
Online Publication Date: 21 September 2005
Conference Date: Sunday 31 July 2005
Conference Location: San Diego, CA, USA
Conference Title: Wavelets XI
Conference Chairs: Manos Papadakis, Andrew F. Laine, Michael A. Unser
Classically,analysis on manifolds and graphs has been based on thestudy of the eigenfunctions of the Laplacian and its generalizations.These objects from differential geometry and analysis on manifolds haveproven useful in applications to partial differential equations, and theirdiscrete counterparts have been applied to optimization problems, learning, clustering,routing and many other algorithms.17 The eigenfunctions of the Laplacianare in general global: their support often coincides with thewhole manifold, and they are affected by global properties ofthe manifold (for example certain global topological invariants). Recently aframework for building natural multiresolution structures on manifolds and graphswas introduced, that greatly generalizes, among other things, the constructionof wavelets and wavelet packets in Euclidean spaces.8,9 This allowsthe study of the manifold and of functions on itat different scales, which are naturally induced by the geometryof the manifold. This construction proceeds bottom-up, from the finestscale to the coarsest scale, using powers of a diffusionoperator as dilations and a numerical rank constraint to criticallysample the multiresolution subspaces. In this paper we introduce anovel multiscale construction, based on a top-down recursive partitioning inducedby the eigenfunctions of the Laplacian. This yields associated localcosine packets on manifolds, generalizing local cosines in Euclidean spaces.10We discuss some of the connections with the construction ofdiffusion wavelets. These constructions have direct applications to the approximation,denoising, compression and learning of functions on a manifold andare promising in view of applications to problems in manifoldapproximation, learning, dimensionality reduction.