Publications by Gilles Baechler

Lippmann Photography: A Signal Processing Perspective

Martin Vetterli, Gilles Baechler, Arnaud Latty, Adam James Scholefield, Michalina Wanda Pacholska

Lippmann (or interferential) photography is the first and only analog photography method that can capture the full color spectrum of a scene in a single take. This technique, invented more than a hundred years ago, records the colors by creating interferen ...

2022

Shedding light on 19th century spectra by analyzing Lippmann photography

Martin Vetterli, Gilles Baechler, Arnaud Latty, Adam James Scholefield, Michalina Wanda Pacholska

2021

Coordinate Difference Matrices

Martin Vetterli, Gilles Baechler, Golnooshsadat Elhami, Miranda Krekovic

In many problems such as phase retrieval, molecular biology, source localization, and sensor array calibration, one can measure vector differences between pairs of points and attempt to recover the position of these points; this class of problems is called ...

SIAM PUBLICATIONS2020

Multi-spectral image priniting method

Martin Vetterli, Yves Bellouard, Gilles Baechler, Arnaud Latty, Adam James Scholefield, Michalina Wanda Pacholska

The present disclosure concerns a multi-spectral image printing method. The method includes the steps of: - providing a multi-spectral image; - providing a material; - determining changes in a refractive index value of the material permitting to reproduce ...

2019

Embedded Polarizing Filters to Separate Diffuse and Specular Reflection

Gilles Baechler, Laurent Valentin Jospin, Adam James Scholefield

Polarizing filters provide a powerful way to separate diffuse and specular reflection; however, traditional methods rely on several captures and require proper alignment of the filters. Recently, camera manufacturers have proposed to embed polarizing micro ...

SPRINGER INTERNATIONAL PUBLISHING AG2019

Super Resolution Phase Retrieval for Sparse Signals

Martin Vetterli, Amina Chebira, Gilles Baechler, Juri Ranieri, Miranda Krekovic

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 to recover the phase information of a signal from the magnitude of its Fo ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2018

Structure from sound with incomplete data

Martin Vetterli, Gilles Baechler, Ivan Dokmanic, Miranda Krekovic

In this paper, we consider the problem of jointly localizing a microphone array and identifying the direction of arrival of acoustic events. Under the assumption that the sources are in the far field, this problem can be formulated as a constrained low-ran ...

2018

Sampling the Multiple Facets of Light

Gilles Baechler

The theme of this thesis revolves around three important manifestations of light, namely its corpuscular, wave and electromagnetic nature. Our goal is to exploit these principles to analyze, design and build imaging modalities by developing new signal proc ...

EPFL2018

Combining Range and Direction for Improved Localization

Martin Vetterli, Robin Scheibler, Gilles Baechler, Frederike Dümbgen, Golnooshsadat Elhami, Miranda Krekovic, Adam James Scholefield

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 ...

2018

Sampling and Exact Reconstruction of Pulses with Variable Width

Martin Vetterli, Loïc Arnaud Baboulaz, Gilles Baechler, Adam James Scholefield

Recent sampling results enable the reconstruction of signals composed of streams of fixed-shaped pulses. These results have found applications in topics as varied as channel estimation, biomedical imaging and radio astronomy. However, in many real signals, ...

Institute of Electrical and Electronics Engineers2017

Indoor localization method and system

Martin Vetterli, Gilles Baechler, Reza Parhizkar

An indoor localization method for estimating the location of nodes (n1, n2), at least one node (n1) being connected to at least another node (n2) by at least two different channels (ch1, ch1′), comprising the following steps: measuring a distance between t ...

2015

Finite Rate of Innovation Based Modeling and Compression of ECG Signals

Gilles Baechler, Nikolaos Freris

Mobile health is gaining increasing importance for society and the quest for new power efficient devices sampling biosignals is becoming critical. We discuss a new scheme called Variable PulseWidth Finite Rate of Innovation (VPW-FRI) to model and compress ...

2013