Pierre Vandergheynst

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This paper proposes a tree-based pursuit algorithm that efficiently trades off complexity and approximation performance for overcomplete signal expansions. Finding the sparsest representation of a signal using a redundant dictionary is, in general, a NP-Ha ...

This work presents an improved coefficient decoding method for Matching Pursuit streams. It builds on the adaptive a posteriori quantization of coefficients, and implements an interpolation scheme that enhances the inverse quantization performance at the decoder. A class of interpolation functions is introduced, that capture the behavior of coefficients after conditional scalar quantization. The accuracy of the interpolation scheme is verified experimentally, and the novel decoding algorithm is further eval

An omnidirectional sensor array system, for example a panoptic camera, comprising a plurality of sensors arranged on a support of predetermined shape to acquire data, wherein said sensors are directional and wherein each sensor is attached to a processing ...

We build wavelets on the 2-Hyperboloid. First, we define dilations on the hyperboloid through conic projection. Then, incorporating hyperbolic motions belonging to

SO_0(1,2)

, we define a family of hyperbolic wavelets. The continuous wavelet transform (CWT)is obtained by convolution of the scaled wavelets with the signal. This wavelet transform is proved to be invertible whenever wavelets satisfy a particular admissibility condition. Finally, the Euclidean limit of this CWT on the hyperboloid is considered

Dense three-dimensional reconstruction of a scene from images is a challenging task. Usually, it is achieved by finding correspondences in successive images and computing the distance by means of epipolar geometry. In this paper, we propose a variational f ...

This paper presents a Rate-Distortion analysis for a simple horizon edge image model. A quadtree with anisotropy and rotation is performed on this kind of image, giving a toy model for a non-linear adaptive coding technique, and its Rate-Distortion behavior is studied. The effect of refining the quadtree decomposition is also analyzed.

A fast and exact algorithm is developed for the spin +-2 spherical harmonics transforms on equi-angular pixelizations on the sphere. It is based on the Driscoll and Healy fast scalar spherical harmonics transform. The theoretical exactness of the transform ...

Spectral clustering has become a popular technique due to its high performance in many contexts. It comprises three main steps: create a similarity graph between N objects to cluster, compute the first k eigenvectors of its Laplacian matrix to define a fea ...

In this paper, we propose a generalization of convolutional neural networks (CNN) to non-Euclidean domains for the analysis of deformable shapes. Our construction is based on localized frequency analysis (a generalization of the windowed Fourier transform ...

We propose a novel algorithm for source signals estimation from an underdetermined convolutive mixture assuming known mixing filters. Most of the state-of-the-art methods are dealing with anechoic or short reverberant mixture, assuming a synthesis sparse p ...

We present a method for joint reconstruction of a set of images representing a given scene from few multi-view measurements obtained by compressed sensing. We model the correlation between measurements using global geometric transformations represented by ...

The invention relates to a system and method to optimize navigation and recommendation in a distributed network of media libraries. According to the invention, it is proposed a system and a method to assist the selection of media items comprising the steps ...

Wavelet transform is a powerful instrument in catching zero-dimensional singularities. Ridgelets are a powerful instrument in catching and representing mono-dimensional singularities in bidimensional space. In this paper we propose a hybrid video coder scheme using ridgelet transform for the first approximation of line-edge singularities in displaced frame difference images. We demonstrate the potential of ridgelets and results show substantial improvements when compared to wavelet only based coder.

Numerous applications demand that we manipulate large sets of very high-dimensional signals. A simple yet common example is the problem of finding those signals in a database that are closest to a query. In this paper, we tackle this problem by restricting ...

This paper deals with the problem of efficiently computing the optical flow of image sequences acquired by omnidirectional (nearly full field of view) cameras. We formulate the problem in the natural spherical geometry associated with these devices and ext ...

A method for decomposing a digital image at resolution R and MR into a set of spatial sub-bands of resolution R and MR where MR>R and where the high-band at resolution MR is calculated by subtracting the filtered and up-sampled image at resolution R from t ...

Spectral clustering is a widely studied problem, yet its complexity is prohibitive for dynamic graphs of even modest size. We claim that it is possible to get information from past cluster assignments to expedite computation. Our approach builds on a recen ...

We have recently quantified and validated the potential of the emerging compressed sensing (CS) paradigm for real-time energy-efficient electrocardiogram (ECG) compression on resource-constrained sensors. In the present work, we investigate applying sparsity models to exploit underlying structural information in recovery algorithms. More specifically, re-visiting well-known sparse recovery algorithms, we propose novel model- based adaptations for the robust recovery of compressible signals like ECG. Our res

In this paper, we propose an evolution equation for the active contours in scale spaces. This evolution equation is based on the Polyakov functional that has been first introduced in physics and has been then used in image processing in

In this paper, we propose two approaches to define an evolution equation for the active contours in scale spaces. The evolution equation is based on the Polyakov functional that has been first introduced in physics and has been then used in image processing in

Pierre Vandergheynst

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Tree-Based Pursuit: Algorithm and Properties

An improved decoding scheme for Matching Pursuit Streams

Omnidirectional sensor array system

Wavelets on the 2-Hyperboloid

Fast Structure from Motion for Planar Image Sequences

R-D Analysis of Adaptive Edge Representations

Fast spin +-2 spherical harmonics transforms and application in cosmology

Compressive Spectral Clustering

Learning class-specific descriptors for deformable shapes using localized spectral convolutional networks

Sparse Reverberant Audio Source Separation via Reweighted Analysis

Joint image registration and reconstruction from compressed multi-view measurements

System and method for media library navigation and recommendation

Ridgelet transform applied to motion compensated images

On finding nearest neighbors in a set of compressible signals

Optical Flow and Depth from Motion for Omnidirectional Images using a TV-L1 Variational Framework on Graphs

Method for spatially scalable video coding

Fast Approximate Spectral Clustering for Dynamic Networks

Structured Sparsity Models for Compressively Sensed Electrocardiogram Signals: A Comparative Study

Multiscale Active Contours

Multiscale Active Contours