Search Results for author: Martin Vetterli

Found 19 papers, 7 papers with code

Privacy-Enhancing Optical Embeddings for Lensless Classification

1 code implementation23 Nov 2022 Eric Bezzam, Martin Vetterli, Matthieu Simeoni

In this work, we enhance the privacy provided by lensless imaging by (1) downsampling at the sensor and (2) using a programmable mask with variable patterns as our optical encoder.

Classification

Lippmann Photography: A Signal Processing Perspective

no code implementations13 Jul 2022 Gilles Baechler, Michalina Pacholska, Arnaud Latty, Adam Scholefield, Martin Vetterli

Lippmann photography provides a great opportunity to demonstrate several fundamental concepts in signal processing.

How Asynchronous Events Encode Video

no code implementations9 Jun 2022 Karen Adam, Adam Scholefield, Martin Vetterli

Instead of recording video by capturing frames, event-based cameras have sensors that emit events when their inputs change, thus encoding information in the timing of events.

Event-based vision

Learning rich optical embeddings for privacy-preserving lensless image classification

no code implementations3 Jun 2022 Eric Bezzam, Martin Vetterli, Matthieu Simeoni

In this work, we exploit this unique multiplexing property: casting the optics as an encoder that produces learned embeddings directly at the camera sensor.

Classification Image Classification +1

Asynchrony Increases Efficiency: Time Encoding of Videos and Low-Rank Signals

no code implementations29 Apr 2021 Karen Adam, Adam Scholefield, Martin Vetterli

Event-based sensing can present significant improvements in power efficiency when compared to traditional sampling, because (1) the output is a stream of events where the important information lies in the timing of the events, and (2) the sensor can easily be controlled to output information only when interesting activity occurs at the input.

CPGD: Cadzow Plug-and-Play Gradient Descent for Generalised FRI

no code implementations11 Jun 2020 Matthieu Simeoni, Adrien Besson, Paul Hurley, Martin Vetterli

Since the proximal step does not admit a simple closed-form expression, we propose an inexact PGD method, coined as Cadzow plug-and-play gradient descent (CPGD).

Optimization and Control

Encoding and Decoding Mixed Bandlimited Signals using Spiking Integrate-and-Fire Neurons

1 code implementation21 Oct 2019 Karen Adam, Adam Scholefield, Martin Vetterli

We propose a setup to sample a set of bandlimited signals, by mixing them and sampling the result using different IF-TEMs.

Signal Processing

Sampling and Reconstruction of Bandlimited Signals with Multi-Channel Time Encoding

2 code implementations12 Jul 2019 Karen Adam, Adam Scholefield, Martin Vetterli

In this paper, we show that, when using time encoding machines, reconstruction from multiple channels has a more intuitive solution, and does not require the knowledge of the shifts between machines.

Signal Processing

Bound and Conquer: Improving Triangulation by Enforcing Consistency

no code implementations27 Apr 2018 Adam Scholefield, Alireza Ghasemi, Martin Vetterli

We study the accuracy of triangulation in multi-camera systems with respect to the number of cameras.

On the Accuracy of Point Localisation in a Circular Camera-Array

no code implementations24 Feb 2016 Alireza Ghasemi, Adam Scholefield, Martin Vetterli

Although many advances have been made in light-field and camera-array image processing, there is still a lack of thorough analysis of the localisation accuracy of different multi-camera systems.

SHAPE: Linear-Time Camera Pose Estimation With Quadratic Error-Decay

no code implementations24 Feb 2016 Alireza Ghasemi, Adam Scholefield, Martin Vetterli

We propose a novel camera pose estimation or perspective-n-point (PnP) algorithm, based on the idea of consistency regions and half-space intersections.

Pose Estimation

Where You Are Is Who You Are: User Identification by Matching Statistics

no code implementations9 Dec 2015 Farid M. Naini, Jayakrishnan Unnikrishnan, Patrick Thiran, Martin Vetterli

The accuracy obtained under this optimal method can thus be used to quantify the maximum level of user identification that is possible in such settings.

Euclidean Distance Matrices: Essential Theory, Algorithms and Applications

1 code implementation26 Feb 2015 Ivan Dokmanic, Reza Parhizkar, Juri Ranieri, Martin Vetterli

Euclidean distance matrices (EDM) are matrices of squared distances between points.

Other Computer Science

Recursive Compressed Sensing

no code implementations17 Dec 2013 Nikolaos M. Freris, Orhan Öçal, Martin Vetterli

We introduce a recursive algorithm for performing compressed sensing on streaming data.

A Fast Hadamard Transform for Signals with Sub-linear Sparsity in the Transform Domain

no code implementations7 Oct 2013 Robin Scheibler, Saeid Haghighatshoar, Martin Vetterli

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 $K = O(N^\alpha)$, scales sub-linearly in $N$ for some $0 < \alpha < 1$.

THE EFFECTIVE RANK: A MEASURE OF EFFECTIVE DIMENSIONALITY

1 code implementation EURASIP, EUPSICO 2007 Olivier Roy, Martin Vetterli

Many signal processing algorithms include numerical problems where the solution is obtained by adjusting the value of parameters such that a specific matrix exhibits rank deficiency.

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