Publications de Martin Vetterli

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Self-localization of nodes in a sensor network is typically achieved using either range or direction measurements; in this paper, we show that a constructive combination of both improves the estimation. We propose two localization algorithms that make use ...

Digital technologies reshape the way we interact with our environment, including with artworks. Advanced computational imaging solutions allow having extremely high-resolution digital reproductions of artworks outside museums, presumably increasing artwork ...

Cosine-modulated filter banks (CMFB’s) are filter banks whose impulse responses are obtained by modulating a window with cosines. Among their applications are video and audio compression and multitone modulation. Their continuous- time counterpart is known as local cosine bases. Even though there is an extended literature on the discrete-time case both for single and multiple overlapping, the continuous-time case has received less attention, and only the single overlapping case has been solved. This work gi

We show that the complete information that is available after an image has been encoded is not just an approximate quantized image version, but a whole set of consistent images that contains the original image by necessity. From this starting point, we develop a set of tools to design a new class of encoders for image compression, based on a set decomposition and recombination of image features. As an initial validation, we show the results of an experiment where these tools are used to modify the encoding

Acoustic tomography is a type of inverse problem. The idea of estimating physical quantities that influence sound propagation by measuring the parameters of propagation has proven to be successful in many practical domains, including temperature and wind e ...

In this paper, we study the spatialization of the sound field in rooms, in particular the evolution of the room impulse responses in function of their spatial positions. Thanks to this study, we are now able to predict the sound field in any position knowing the sound field in a certain number of positions in the room. If enough measurements are taken, we are able to completely characterize the sound field of the room at any arbitrary location. Further, we determine the number and the spacing between the mi

In environmental monitoring applications, having multiple cameras focus on common scenery increases robustness of the system. To save energy based on user demand, successive refinement image coding is important, as it allows us to progressively request bet ...

We consider the problem of distributing high-quality video signals over IP multicast in large Local Area Networks (LANs), under real-time delay constraints, and with software-only processing. In a large LAN (such as the network of a university campus, or the network of a large company), the source of channel heterogeneity that the video communications system must cope with is not that of different bandwidth constraints available to each receiver, but it is essentially variations in the available CPU power t

We study the problem of simultaneously reconstructing a polygonal room and a trajectory of a device equipped with a (nearly) collocated omnidirectional source and receiver. The device measures arrival times of echoes of pulses emitted by the source and picked up by the receiver. No prior knowledge about the device’s trajectory is required. Most existing approaches addressing this problem assume multiple sources or receivers, or they assume that some of these are static, serving as beacons. Unlike earlier ap

In this paper, we study the rate constraints required for variable rate video transmission over ATM networks. Our objective is to achieve both good source quality and efficient network utilization. We show that these objectives may not be achieved simultaneously unless both network and source coding considerations are taken into account. In particular, we show that, given a rate constraint, a greedy source coding strategy will reduce the potential for statistical multiplexing gain in the network. We propose

Could bandwidth—one of the most classic concepts in signal processing—have a new purpose? In this paper, we investigate the feasibility of using bandwidth to infer shape from a single image. As a first analysis, we limit our attention to orthographic proje ...

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 ...

A new set of algorithms for transform adaptation in adaptive transform coding is presented. These algorithms are inspired by standard techniques in adaptive finite impulse response (FIR) Wiener filtering and demonstrate that similar algorithms with simple updates exist for tracking principal components (eigenvectors of a correlation matrix). For coding an {N}-dimensional source, the transform adaptation problem is posed as an unconstrained minimization over {K = N(N-1)/2} parameters, and this for two possib

This short report summarizes the contribution of the project 'Java for teaching and research'. A website has been created to allow interested users to download the material produced during the project. The site is reachable at http://lcavwww.epfl.ch/~balmelli/java. Also, the site contains a series of web-based presentations for international conferences and workshops. A CD-ROM containing the full project and the website is available on demand at LCAV. The report gives an introduction to the project and goal

Over the field of complex numbers, it is well-known that if the input is real then it is possible to compute 2 real DFT's with one complex DFT. We extend the result to finite fields and show how to compute m DFT's over GF(q) with one DFT over GF(qm)

A growing and important class of traffic in the Internet is so-called `streaming media,' in which a server transmits a packetized multimedia signal to a receiver that buffers the packets for playback. This playback buffer, if adequately sized, counteracts the adverse impact of delay jitter and reordering suffered by packets as they traverse the network, and if large enough also allows lost packets to be retransmitted before their playback deadline expires. We call this framework for retransmitting lost stre

In this paper, we model a spatially varying channel where a source is moving along a random trajectory with respect to a fixed re- ceiver. The aim is to compute the power spectral density corre- sponding to the channel impulse response as a function of tem ...

Accurate calibration is a requirement of many array signal processing techniques. We investigate the calibration of a transducer array using time delays. We derive a strategy based on the mean square error criterion and discuss how time delays that are not ...

Some past work has suggested that lossy compression can be a good denoising tool. Building on this theme, we make the connection that quantization of transform coefficients approximates the operation of Donoho-Johnstone's wavelet thresholding, to conclude that compression (via coefficient quantization) is appropriate for filtering noise from signal. The method of quantization is scale adaptive and is facilitated by a criterion similar to Rissanen's minimum description length principle. Results show that a s

We present a novel error-correction scheme for sensor networks called Multi-hop Hybrid ARQ (MHARQ). Rather than immediately discard a received corrupt packet, a node buffers it. When two corrupt versions of a packet have been received, a procedure attempts to recover the original packet from the corrupt copies. In addition to improving single-hop communications, MHARQ exploits the spatial diversity arising from the broadcast, multi-point nature of a sensor network. MHARQ therefore also impacts multi-node in

Martin Vetterli

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Combining Range and Direction for Improved Localization

Interactive Digital Engagement With Visual Artworks and Cultural Artefacts Enhances User Aesthetic Experiences in the Laboratory and Museum

Discrete- and continuous-time local cosine bases with multiple overlapping

Set theoretic compression with an application to image coding

Acoustic tomography for scalar and vector fields: theory and application to temperature and wind estimation

The Plenacoustic Function and its Sampling

Distributed Successive Refinement of Multiview Images Using Broadcast Advantage

Video Multicast in (large) local area networks

Look, no beacons! Optimal all-in-one EchoSLAM

Rate constraints for video transmission over ATM networks based on joint source/network criteria

Shape from bandwidth: the 2-D orthogonal projection case

Optimal Sampling Rates in Infinite-Dimensional Compressed Sensing

Adaptive Transform Coding Using LMS-like Principal Component Tracking

Java for Teaching and Research

Computing m DFT's over GF(q) with one DFT over GF(q^m)

Soft ARQ for layered streaming media

On a stochastic version of the plenacoustic function

Robust Array Calibration Using Time Delays with Application to Ultrasound Tomography

Bridging Compression to Wavelet Thresholding as a Denoising Method

Single and Multi-Hop ARQ in Sensor Networks