Publications de Martin Vetterli

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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" ...

We extended Gross's method of volume wavelet rendering by computing splats via an orthogonal projection operator. The method decomposes the volume data into a wavelet pyramid representation in the spline domain. The splats of the basis functions are approximated on a multiresolution grid. Using least-squares approximation ensures the smallest possible error for a given sampling step size. The approximation error on the grid is derived as a function of the sampling step h. The choice of the appropriate wavel

We consider the problem of low-sampling rate high-resolution channel estimation and timing for digital ultra-wideband (UWB) receivers. We extend some of our recent results in sampling of certain classes of parametric non-bandlimited signals and develop a frequency domain method for channel estimation and synchronization in ultra-wideband systems, which uses sub-Nyquist uniform sampling and well-studied computational procedures. In particular, the proposed method can be used for identification of more realis

Apparatus comprising M sensors for measuring the temperature on M locations of the apparatus and an estimator configured to estimate a temperature vector of the apparatus with N temperature variables, whereby the estimator is configured to approximate the ...

We propose FResher Encounter SearcH (FRESH), a simple algorithm for efficient route discovery in mobile ad hoc networks. Nodes keep a record of their most recent encounter times with all other nodes. Instead of searching for the destination, the source node searches for any intermediate node that encountered the destination {\em more recently than did the source node itself}. The intermediate node then searches for a node that encountered the destination yet more recently, and the procedure iterates until t

The successful design of sensor network architectures depends crucially on the structure of the sampling, observation, and communication processes. One of the most fundamental ques- tions concerns the sufficiency of discrete approximations in time, space, ...

The low quality of wireless links leads to perpetual packet losses. While an acknowledgment mechanism is generally used to cope with these losses, multiple retransmissions nevertheless occur. Opportunistic routing limits these retransmissions by taking adv ...

A major limitation of thermal therapies is the lack of detailed thermal information needed to monitor the therapy. Temperatures are routinely measured invasively with thermocouples, but only sparse measurements can be made. Ultrasound tomography is an attr ...

The use of multiresolution (MR) joint source-channel coding in the context of digital terrestrial broadcasting of high-definition television (HDTV) is shown to be an efficient alternative to single-resolution techniques, which suffer from a sharp threshold effect in the fringes of the broadcast area. It is shown how matched multiresolution source and channel coding can provide a stepwise graceful degradation and improve the behavior, in terms of coverage and robustness of the transmission scheme, over syste

Compression of ECG (electrocardiogram) as a signal with finite rate of innovation (FRI) is proposed in this paper. By modelling the ECG signal as the sum of bandlimited and nonuniform linear spline which contains finite rate of innovation (FRI), sampling t ...

We present LCAV-31, a multi-view object recognition dataset designed specifically for benchmarking light field image analysis tasks. The principal distinctive factor of LCAV-31 compared to similar datasets is its design goals and availability of novel visu ...

An 8-point Fourier-cosine transform chip designed for a data rate of 100 Mbits/s is described. The top-down design is presented step by step, including algorithm modification for VLSI suitability, architectural choices, testing overhead, internal precision assignments, mask generation, and finally, verification of the layout. A high-level language (C) design tool was developed concurrently with the layout. This tool allows mimicking exactly the different representations of the algorithm: software, mask, and

Wave field synthesis (WFS) is a prevalent approach to multiple-loudspeaker sound reproduction for an extended listening area. Although powerful as a theoretical concept, its deployment is hampered by practical limitations due to diffraction, aliasing, and the effects of the listening room. Reconstructing the desired sound field in the listening area, accounting for the medium propagation characteristic, is another approach termed as sound field reconstruction (SFR). It is based on the essential band-limited

We study the oversampled binary image sensor in [1] under noisy scenario. The binary image sensor is similar to traditional photographic film with pixel value equal to "0" or "1". The potential application of the oversampled binary image sensor is high dyn ...

Spectral factorization is a classical tool in signal processing and communications. It also plays a critical role in X-ray crystallography, in the context of phase retrieval. In this work, we study the problem of sparse spectral factorization, aiming to recover a one-dimensional sparse signal from its autocorrelation. We present a sufficient condition for the recovery to be unique, and propose an iterative algorithm that can obtain the original signal (up to a sign change, time-shift and time-reversal). Num

Third harmonic generation (THG) microscopy offers label-free imaging and enables three-dimensional imaging with inherently good optical depth-sectioning. Its utility is important for imaging and characterization of laser-induced changes in transparent materials. Here we develop a digital twin for THG microscopy that allows accurate simulation of experiments and provides insight into desired information such as the third-order nonlinear susceptibility tensor. It also enables accurate simulation of the instru

We introduce a novel, adaptive image representation using spatially varying wavelet packets (WPs), Our adaptive representation uses the fast double-tree algorithm introduced previously (Herley et al., 1993) to optimize an operational rate-distortion (R-D) cost function, as is appropriate for the lossy image compression framework. This involves jointly determining which filter bank tree (WP frequency decomposition) to use, and when to change the filter bank tree (spatial segmentation). For optimality, the sp

A simple algorithm for the evaluation of discrete Fourier transforms (DFT) and discrete cosine transforms (DCT) is presented. This approach, based on the divide and conquer technique, achieves a substantial decrease in the number of additions when compared to currently used FFT algorithms (30% for a DFT on real data, 15% for a DFT on complex data and 25% for a DCT) and keeps the same number of multiplications as the best known FFT algorithms. The simple structure of the algorithm and the fact that it is bes

The ridgelet transform (Candès and Donoho, 1999) was introduced as a sparse expansion for functions on continuous spaces that are smooth away from discontinuities along lines. In this paper, we propose an or- thonormal version of the ridgelet transform for discrete and fi- nite-size images. Our construction uses the finite Radon transform (FRAT) (Bolker, 1987:Matùs and Flusser, 1993) as a building block. To overcome the periodiza- tion effect of a finite transform, we introduce a novel ordering of the FRAT

We consider the problem of reconstructing superimposed temperature and wind flow fields from acoustic measurements. A new technique based solely on acoustic waves propagation is presented. In contrast to the usual straight ray assumption, a bent ray model is considered in order to achieve higher accuracy. Under this assumption, we propose an iterative reconstruction algorithm that allows to entirely recover the considered fields. It alternates between estimating the fields of interest and the corresponding

Martin Vetterli

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Event-Driven Video Coding for Outdoor Wireless Monitoring Cameras

Wavelet Projections for Volume Rendering

Low-Sampling Rate UWB Channel Characterization and Synchronization

Method to determine the distribution of temperature sensors

Age Matters: Efficient Route Discovery in Mobile Ad Hoc Networks Using Encounter Ages

Sensing and communication with and without bits

Potentials of Opportunistic Routing in Energy-Constrained Wireless Sensor Networks

Temperature Monitoring During Tissue Freezing Using Ultrasound Speed Measurements

Multiresolution broadcast for digital HDTV using joint source-channel coding

Compression of ECG as a Signal with Finite Rate of Innovation

LCAV-31: a dataset for light field object recognition

A discrete Fourier-cosine transform chip

Sound Field Reconstruction: An Improved Approach For Wave Field Synthesis

Oversampled Noisy Binary Image Sensor

Sparse spectral factorization: Unicity and Reconstruction Algorithms

Leveraging computational imaging for enhanced third-harmonic generation microscopy

Adaptive transforms for image coding using spatially varying wavelet packets

Simple FFT and DCT algorithms with reduced number of operations

The finite ridgelet transform for image representation

Acoustic Tomography Method for Measuring Temperature and Wind Velocity