Publications de Laurent Jacques

From Bits to Images: Inversion of Local Binary Descriptors

Pierre Vandergheynst, Alexandre Massoud Alahi, Laurent Jacques, Emmanuel D'Angelo

Local Binary Descriptors are becoming more and more popular for image matching tasks, especially when going mobile. While they are extensively studied in this context, their ability to carry enough information in order to infer the original image is seldom ...

Institute of Electrical and Electronics Engineers2014

The PANOPTIC Camera: A Plenoptic Sensor with Real-Time Omnidirectional Capability

Alexandre Schmid, Yusuf Leblebici, Pierre Vandergheynst, Luigi Bagnato, Laurent Jacques, Hossein Afshari

A new biologically-inspired vision sensor made of one hundred "eyes" is presented, which is suitable for real-time acquisition and processing of 3-D image sequences. This device, named the Panoptic camera, consists of a layered arrangement of approximately ...

Springer Verlag2013

Omnidirectional sensor array system

Alexandre Schmid, Yusuf Leblebici, Pierre Vandergheynst, Luigi Bagnato, Laurent Jacques, Hossein Afshari

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 ...

2012

Hardware Implementation of an Omnidirectional Camera with Real-Time 3D Imaging Capability

Alexandre Schmid, Yusuf Leblebici, Pierre Vandergheynst, Luigi Bagnato, Laurent Jacques, Hossein Afshari

A novel hardware implementation of an omnidirectional image sensor is presented which is capable of acquiring and processing 3D image sequences in real time. The system consists of a hemispherical arrangement of a large number of CMOS imagers, connecting t ...

Ieee Service Center, 445 Hoes Lane, Po Box 1331, Piscataway, Nj 08855-1331 Usa2011

Sparsity Driven People Localization with a Heterogeneous Network of Cameras

Pierre Vandergheynst, Alexandre Massoud Alahi, Laurent Jacques

In this paper, we propose to study the problem of localization of a dense set of people with a network of heterogeneous cameras. We propose to recast the problem as a linear inverse problem. The proposed framework is generic to any scene, scalable in the n ...

Springer Verlag2011

A (256x256) Pixel 76.7mW CMOS Imager/ Compressor Based on Real-Time In-Pixel Compressive Sensing

Alexandre Schmid, Yusuf Leblebici, Pierre Vandergheynst, Vahid Majidzadeh Bafar, Laurent Jacques

A CMOS imager is presented which has the abil- ity to perform localized compressive sensing on-chip. In-pixel convolutions of the sensed image with measurement matrices are computed in real time, and a proposed programmable two- dimensional scrambling tech ...

IEEE Service Center, 445 Hoes Lane, Po Box 1331, Piscataway, Nj 08855-1331 Usa2010

Compressed sensing for radio interferometry: prior-enhanced Basis Pursuit imaging techniques

Pierre Vandergheynst, Yves Wiaux, Gilles Puy, Laurent Jacques

We propose and assess the performance of new imaging techniques for radio interferometry that rely on the versatility of the compressed sensing framework to account for prior information on the signals. The present manuscript represents a summary of recent ...

2009

CMOS Compressed Imaging by Random Convolution

Alexandre Schmid, Yusuf Leblebici, Pierre Vandergheynst, Vahid Majidzadeh Bafar, Laurent Jacques

We present a CMOS imager with built-in capability to perform Compressed Sensing. The adopted sensing strategy is the random Convolution due to J. Romberg. It is achieved by a shift register set in a pseudo-random configuration. It acts as a convolutive fil ...

2009

Dequantizing Compressed Sensing with non-Gaussian Constraints

Laurent Jacques

The theory of Compressed Sensing (CS) is based on reconstructing sparse signals from random linear measurements. As measurement of continuous signals by digital devices always involves some form of quantization, in practice devices based on CS encoding mus ...

2009

Compressive Sampling of Pulse Trains : Spread the Spectrum !

Pierre Vandergheynst, Rémi Gribonval, Laurent Jacques

In this paper we consider the problem of sampling far below the Nyquist rate signals that are sparse linear superpositions of shifts of a known, potentially wide-band, pulse. This signal model is key for applications such as Ultra Wide Band (UWB) communica ...

2009

Compressed sensing imaging techniques for radio interferometry

Pierre Vandergheynst, Yves Wiaux, Gilles Puy, Laurent Jacques

Radio interferometry probes astrophysical signals through incomplete and noisy Fourier measurements. The theory of compressed sensing demonstrates that such measurements may actually suffice for accurate reconstruction of sparse or compressible signals. We ...

Wiley-Blackwell2009

TV-Regularized Generation of Planar Images from Omnicams

Pascal Frossard, Pierre Vandergheynst, Didier Raboud, Laurent Jacques

This paper addresses the problem of mapping images between different vision sensors. Such a mapping could be modeled as a sampling problem that has to encompass the change of geometry between the two sensors and the specific discretization of the real scen ...

2009

Sparsity-driven People Localization Algorithm: Evaluation in Crowded Scenes Environments

Pierre Vandergheynst, Alexandre Massoud Alahi, Laurent Jacques

We propose to evaluate our sparsity driven people localization framework on crowded complex scenes. The problem is recast as a linear inverse problem. It relies on deducing an occupancy vector, i.e. the discretized occupancy of people on the ground, from t ...

2009

Shape from Texture for Omnidirectional Images

Pierre Vandergheynst, Eugenio De Vito, Luigi Bagnato, Laurent Jacques

In this paper, we describe a method to infer 3-D scene information using a single view captured by an omnidirectional camera. The proposed technique is inscribed in the so called ``Shape from Texture'' problem : if the textures hold by 3-D surfaces respect ...

2008

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

Pierre Vandergheynst, Yves Wiaux, Laurent Jacques

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 ...

2007

Fast directional correlation on the sphere with steerable filters

Pierre Vandergheynst, Yves Wiaux, Laurent Jacques

A fast algorithm is developed for the directional correlation of scalar band-limited signals and band-limited steerable filters on the sphere. The asymptotic complexity associated to it through simple quadrature is of order O(L^5), where 2L stands for the ...

2006

Correspondence principle between spherical and Euclidean wavelets

Pierre Vandergheynst, Yves Wiaux, Laurent Jacques

Wavelets on the sphere are reintroduced and further developed independently of the original group theoretic formalism, in an equivalent, but more straightforward approach. These developments are motivated by the interest of the scale-space analysis of the ...

2005

Stereographic Wavelet Frames on the Sphere

Pierre Vandergheynst, Iva Bogdanova Vandergheynst, Laurent Jacques

In this paper we exploit the Continuous Wavelet Transform (CWT) on the two dimensional sphere, introduced previously by two of us, to build associated Discrete Wavelet Frames. We first explore half-continuous frames, i.e., frames where the position remains ...

2005