Concept

Ambiguity function

Publications associées (16)

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Versatile shaping of optical frequency combs and applications

Jianqi Hu

Optical frequency combs are a series of phase-locked and equidistant laser lines in the spectral domain. In the time domain, they correspond to periodic pulse trains by the Fourier relation. The ability to shape optical combs and pulse trains is pivotal to ...

EPFL2021

A stability theory beyond the co-rotational setting for critical wave maps blow up

Joachim Krieger, Shuang Miao

We exhibit non-equivariant perturbations of the blowup solutions constructed in [18] for energy critical wave maps into

\mathbb{S}^2

. Our admissible class of perturbations is an open set in some sufficiently smooth topology and vanishes near the light co ...

2020

Super Resolution Phase Retrieval for Sparse Signals

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

Sensing the real world

Juri Ranieri

A sensor is a device that detects or measures a physical property and records, indicates, or otherwise responds to it. In other words, a sensor allows us to interact with the surrounding environment, by measuring qualitatively or quantitatively a given phe ...

EPFL2014

Optical Nyquist-pulse generation with a power difference to the ideal sinc-shape sequence of < 1%

Luc Thévenaz, Marcelo Alfonso Soto Hernandez, Mohammad Amin Shoaie, Mohammad Mehdi Alem Karladani

Sinc-shaped Nyquist-pulses possess a rectangular spectrum. Thus, a sinc-pulse transmission minimizes the carrier spacing down to the baud rate, and therefore, substantially increases the transmissible data rates. These perspectives have led to a strong res ...

VDE Verlag GmbH2013

Role of sampling in evaluating classical time autocorrelation functions

Jiri Vanicek, Tomas Zimmermann

We analyze how the choice of the sampling weight affects efficiency of the Monte Carlo evaluation of classical time autocorrelation functions. Assuming uncorrelated sampling or sampling with constant correlation length, we propose a sampling weight for whi ...

American Institute of Physics2013

Phase Retrieval for Sparse Signals: Uniqueness Conditions

Martin Vetterli, Yue Lu, Juri Ranieri, Amina Chebira

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 the recovery of the phase information of a signal from the magnitude of i ...

2013

Image Segmentation With Background Correction Using A Multiplicative Smoothing-Spline Model

Michaël Unser, Aurélien Bourquard, Ramtin Madani

This paper presents an image-segmentation method which compensates multiplicative distortions based on smooth regularity assumptions. In this work, we generalize the original Chan-Vese functional to handle a continuous multiplicative bias. In the derivatio ...

Ieee2012

Image Segmentation with Background Correction Using a Multiplicative Smoothing-Spline Model

Michaël Unser, Aurélien Bourquard, Ramtin Madani

IEEE2012

The autocorrelation function for island areas on self-affine surfaces

Jean-François Molinari, Guillaume Anciaux, Srinivasa Babu Ramisetti

The spatial distribution of regions that lie above contours of constant height through a self-affine surface is studied as a function of the Hurst exponent H. If the surface represents a landscape, these regions correspond to islands. When the surface repr ...

2011

A stability theory beyond the co-rotational setting for critical wave maps blow up

Joachim Krieger, Shuang Miao

We exhibit non-equivariant perturbations of the blowup solutions constructed in [18] for energy critical wave maps into

\mathbb{S}^2

. Our admissible class of perturbations is an open set in some sufficiently smooth topology and vanishes near the light co ...

2020