Publications de Martin Vetterli

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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 ...

We are proposing an interpolation technique for head related transfer functions (HRTFs). For deriving the algorithm we study the dual problem where sound is emitted from the listener’s ear and the generated sound field is recorded along a circular array of ...

A compelling method to calibrate the positions of microphones in an array is with sources at unknown locations. Remarkably, it is possible to reconstruct the locations of both the sources and the receivers, if their number is larger than some prescribed mi ...

The split-radix algorithm for the discrete Fourier transform of length-2^m is by now fairly popular. First, we give the reason why the split-radix algorithm is better tant any single-radix algorithm on length 2^m DFT's. Then, the split-radix approach is generalized to length-p^m DFT's. It is shown that whenever a radix-p^2 outperforms a radix-p / p^2 algorithm will outperform both of them. As an exemple, a radix-3/9 algorithm is developed for length 3^m DFT's.

Gossip algorithms have recently received significant attention, mainly because they constitute simple and robust algorithms for distributed information processing over networks. However for many topologies that are realistic for wireless ad-hoc and sensor networks (like grids and random geometric graphs), the standard nearest-neighbor gossip converges very slowly. A recently proposed algorithm called geographic gossip improves gossip efficiency by a

\sqrt{n / \log n}

factor for random geometric graphs, by

We study an iterative, locally quadratically convergent algorithm for solving Toeplitz systems of equations from [R. P. Brent, F. G. Gustavson and D. Y. Y. Yun. ''Fast solution of Toeplitz systems of equations and computation of Pade approximations'', J. Algorithms, 1:259-295, 1980]. We introduce a new iterative algorithm that is locally quadratically convergent when used to solve symmetric positive definite Toeplitz systems. We present a set of numerical experiments on randomly generated symmetric positive

Lately, the use of ultrafast in-volume laser-based processing of transparent materials has gained ground as a 3D-printing method of functional materials, photonics devices and high-density storage media. In this talk, we discuss the use of wide-field third-harmonic imaging that offers a non-destructive means for investigating and characterizing laser-written in-volume complex structures. Specifically, the method is used for identifying laser-induced modifications and establishing their taxonomy over a large

A novel algorithm is introduced for estimating the echo path responses for stereophonic acoustic echo cancellation. When the Wiener solution for the echo path responses is non-unique, the echo paths are estimated in two stages. In a first stage, one of the ...

We propose a stochastic model for video and compute its information rates. The model has two sources of information representing ensembles of camera motion and visual scene data (i.e. "realities"). The sources of information are combined generating a vecto ...

Super-resolution algorithms reconstruct a high resolution image from a set of low resolution images of a scene. Precise alignment of the input images is an essential part of such algorithms. If the low resolution images are undersampled and have aliasing a ...

The light transport matrix has become a powerful tool for scene relighting, owing to the versatility of its representational power of various light transport phenomenon. We argue that scenes with an almost planar surface geometry, even with significant amo ...

We propose an algorithm (SCS-FRI) to estimate multipath channels with Sparse Common Support (SCS) based on Finite Rate of Inno- vation (FRI) sampling. In this setup, theoretical lower-bounds are derived, and simulation in a Rayleigh fading environment show ...

The computational complexity of running FIR (finite-impulse response) and IIR (infinite-impulse response) filtering using multirate filter banks is considered. No restrictions are put on signal, filter, or block lengths. It is shown how to map long running convolutions into smaller ones by using filter banks based on aperiodic convolution algorithms and short-time Fourier transforms. With the proposed approach, good tradeoffs among computational complexity, system architecture, and input-output delay are ac

Reconstruction method and devices for two-dimensional signals that are not bandlimited but have a parametric representation with a finite number of degrees of freedom. The signal is reconstructed from the samples obtained after a suitable filtering with a smoothing kernel. Projection techniques allow reducing the problem to a combination of one-dimensional subproblems.

A system is proposed in order to split a multi-dimensional signal into N sub-bands, which are then subsampled by N. Subsequent upsampling and filtering allows the recovery of the original signal. Main features are a good bandpass characteristic of the channels, automatic aliasing cancellation and spectral invariance of the overall system. The one dimensional case, known as the quadrature mirrir filter (QMF, [1]), is generalized for both the separable and the non-separable case. A parallel implementation, ba

Recently, it was shown that it is possible to develop exact sampling schemes for a large class of parametric nonban- dlimited signals, namely certain signals of finite rate of innovation. A common feature of such signals is that they have a finite number o ...

An exact analysis of the critically subsampled two-band modelization scheme is given, and it is demonstrated that adaptive cross-filters between the subbands are necessary for modelization with small output errors. It is shown that perfect reconstruction filter banks can yield exact modelization. These results are extended to the critically subsampled multiband schemes, and important computational savings are seen to be achieved by using good quality filter banks. The problem of adaptive identification in c

Perfect reconstruction finite impulse-response (FIR) filter banks are analyzed both in the z-transform and time domains, showing the alternatives between designs in the two domains. Various classes of perfect reconstruction schemes are indicated, and relations between previously known systems are given. Windowed modulated filter banks with low computational complexity and perfect reconstruction are shown. New factorizations of polyphase filter matrices leading in particular to linear-phase filters, are give

We present a new technique for estimating the specular peak of the bidirectional reflectance distribution function (BRDF) based on finite rate of innovation (FRI) sampling. The specular component of the BRDF varies rapidly, so it is challenging to acquire it by pointwise sampling. Yet, the knowledge of its precise location is key to render realistically complex materials. We show how to adapt the FRI framework to accurately determine the location of a single pulse when the sampling kernel is unknown. We use

Wavelet or sub–band coding has been quite successful in compression applications, and this success can be attributed in part to the good approximation properties of wavelets. In this paper, we revisit rate–distortion (RD) bounds for the wavelet approximation of piecewise smooth functions, and piecewise polynomial functions in particular. We contrast these results with RD bounds achievable using an oracle–based method. We then introduce a practical dynamic programming algorithm, which achieves performance si

Martin Vetterli

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The Fukushima Inverse Problem

Head Related Transfer Functions Interpolation Considering Acoustics

How to Localize Ten Microphones in One Fingersnap

Split-radix algorithms for length-p^m DFT's

Gossip along the way: order-optimal consensus through randomized path averaging

Iterative Toeplitz solvers with local quadratic convergence

Wide-field third-harmonic imaging of femtosecond laser-induced in-volume modifications

Two Stage Estimation for the Echo Paths in Stereophonic Acoustic Echo Cancellation

A Stochastic Model for Video and its Information Rates

A Frequency Domain Approach to Registration of Aliased Images with Application to Super-Resolution

Light Transport Matrix recovery for nearly planar objects

Estimating Sparse MIMO Channels Having Common Support

Running FIR and IIR filtering using filter banks

Sampling method reconstruction method and devices for sampling and/or reconstructing multidimensional signals

Multi-dimensional subband coding: some theory and algorithms

Sampling and Reconstruction of Signals with Finite Rate of Innovation in the Presence of Noise

Adaptive filtering in sub-bands with critical sampling: analysis, experiments, and application to acoustic echo cancellation

Perfect reconstruction FIR filter banks: some properties and factorizations

Accurate recovery of a specularity from a few samples of the reflectance function

Approximation and compression of piecewise smooth functions