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Martin Vetterli

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Publications associées (262)

Sampling and Reconstruction of Spatial Fields using Mobile Sensors

Martin Vetterli, Jayakrishnan Unnikrishnan

Spatial sampling is traditionally studied in a static setting where static sensors scattered around space take measurements of the spatial field at their locations. In this paper we study the emerging paradigm of sampling and reconstructing spatial fields ...

Institute of Electrical and Electronics Engineers2013

Fast and robust estimation of jointly sparse channels

Martin Vetterli, Yann Barbotin, Ali Hormati

A device and method for estimating multipath jointly sparse channels. The method comprises receiving a number K of signal components by a number P of receiving antennas, where P≧2. The method further comprises estimating the sparsity condition of the multi ...

2013

Sampling and reconstructing diffusion fields in presence of aliasing

Martin Vetterli, Juri Ranieri

The reconstruction of a diffusion field, such as temperature, from samples collected by a sensor network is a classical inverse problem and it is known to be ill-conditioned. Previous work considered source models, such as sparse sources, to regularize the ...

2013

Phase Retrieval for Sparse Signals: Uniqueness Conditions

Martin Vetterli, Amina Chebira, Yue Lu, Juri Ranieri

In a variety of fields, in particular those involving imaging and optics, we often measure signals whose phase is missing or has been irremediably distorted. Phase retrieval attempts the recovery of the phase information of a signal from the magnitude of i ...

2013

Calibration Using Matrix Completion with Application to Ultrasound Tomography

Martin Vetterli, Amin Karbasi, Reza Parhizkar

We study the calibration process in circular ultrasound tomography devices where the sensor positions deviate from the circumference of a perfect circle. This problem arises in a variety of applications in signal processing ranging from breast imaging to s ...

Institute of Electrical and Electronics Engineers2013

Sequences with Minimal Time-Frequency Spreads

Martin Vetterli, Yann Barbotin, Reza Parhizkar

For a given time or frequency spread, one can always find continuous- time signals, which achieve the Heisenberg uncertainty principle bound. This is known, however, not to be the case for discrete-time sequences; only widely spread sequences asymptoticall ...

Ieee2013

On Optimal Sampling Trajectories for Mobile Sensing

Martin Vetterli, Jayakrishnan Unnikrishnan

We study the design of sampling trajectories for stable sampling and reconstruction of bandlimited spatial fields using mobile sensors. As a performance metric we use the path density of a set of sampling trajectories, defined as the total distance travele ...

2013

Randomized recovery for boolean compressed sensing

Martin Vetterli, Mitra Fatemi

We consider the problem of boolean compressed sensing, which is alternatively known as group testing. The goal is to recover a small number of defective items in a large set from a few collective binary tests. This problem can be formulated as a binary lin ...

2013

The Fukushima Inverse Problem

Martin Vetterli, Robin Scheibler, Juri Ranieri, Ivan Dokmanic, Marta Martinez-Camara

Knowing what amount of radioactive material was released from Fukushima in March 2011 and at what time instants is crucial to assess the risk, the pollution, and to understand the scope of the consequences. Moreover, it could be used in forward simulations ...

2013

Sampling High-Dimensional Bandlimited Fields on Low-Dimensional Manifolds

Martin Vetterli, Jayakrishnan Unnikrishnan

Consider the task of sampling and reconstructing a bandlimited spatial field in

\Re^2

using moving sensors that take measurements along their path. It is inexpensive to increase the sampling rate along the paths of the sensors but more expensive to incre ...

Institute of Electrical and Electronics Engineers2013

Optimal Sampling Rates in Infinite-Dimensional Compressed Sensing

Martin Vetterli, Loïc Arnaud Baboulaz, Mitra Fatemi

The theory of compressed sensing studies the problem of recovering a high dimensional sparse vector from its projections onto lower dimensional subspaces. The recently introduced framework of infinite-dimensional compressed sensing [1], to some extent gene ...

2013

Acoustic Echoes Reveal Room Shape

Martin Vetterli, Reza Parhizkar, Yue Lu, Andreas Walther, Ivan Dokmanic

Imagine that you are blindfolded inside an unknown room. You snap your fingers and listen to the room’s response. Can you hear the shape of the room? Some people can do it naturally, but can we design computer algorithms that hear rooms? We show how to com ...

National Academy of Sciences2013

Light ﬁeld panorama by a plenoptic camera

Martin Vetterli, Paolo Prandoni, Loïc Arnaud Baboulaz, Zhou Xue

Consumer-grade plenoptic camera Lytro draws a lot of interest from both academic and industrial world. However its low resolution in both spatial and angular domain prevents it from being used for ﬁne and detailed light ﬁeld acquisition. This paper propose ...

SPIE2013

A Fast Hadamard Transform for Signals with Sub-linear Sparsity

Martin Vetterli, Robin Scheibler, Saeid Haghighatshoar

A new iterative low complexity algorithm has been presented for computing the Walsh-Hadamard transform (WHT) of an N dimensional signal with a K-sparse WHT, where N is a power of two and K = O(N^α), scales sub- linearly in N for some 0 < α < 1. Assuming a ...

2013

A method and apparatus for image acquisition and conversion

Martin Vetterli, Feng Yang, Yue Lu

Method for image acquisition and conversion comprising: low-pass filtering an image by an acquisition lens, producing from said low-pass filtered image an up-sampled image with a first resolution with an up-sampling factor using a image sensor, converting ...

2012

Locating the Source of Diffusion in Large-Scale Networks

Patrick Thiran, Martin Vetterli, Pedro Pereira Correia Pinto

How can we localize the source of diffusion in a complex network? Due to the tremendous size of many real networks---such as the Internet or the human social graph---it is usually infeasible to observe the state of all nodes in a network. We show that it i ...

American Physical Society2012

Sampling and reconstructing spatial fields using mobile sensors

Martin Vetterli, Jayakrishnan Unnikrishnan

The classical approach to sampling time-invariant spatial fields uses static sensors distributed over space. We study a new approach involving mobile sensors that move through space measuring the field values along their paths. A single moving sensor can t ...

Ieee2012

How is the Weather: Automatic Inference from Images

Martin Vetterli, Guillermo Barrenetxea Kobas, Feng Yang, Zichong Chen, Albrecht Johannes Lindner

Low-cost monitoring cameras/webcams provide unique visual information. To take advantage of the vast image dataset captured by a typical webcam, we consider the problem of retrieving weather information from a database of still images. The task is to autom ...

2012

Bits from Photons: Oversampled Image Acquisition Using Binary Poisson Statistics

Martin Vetterli, Luciano Sbaiz, Feng Yang, Yue Lu

We study a new image sensor that is reminiscent of traditional photographic film. Each pixel in the sensor has a binary response, giving only a one-bit quantized measurement of the local light intensity. To analyze its performance, we formulate the oversam ...

Institute of Electrical and Electronics Engineers2012

Event-Driven Video Coding for Outdoor Wireless Monitoring Cameras

Martin Vetterli, Guillermo Barrenetxea Kobas, Zichong Chen

Reducing communication cost is crucial for outdoor wireless monitoring cameras which are constrained by limited energy budgets. From event detection point of view, traditional video coding schemes such as H.264 are inefficient as they ignore the "meaning" ...

2012

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