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Concept

Sonar

Related publications (20)

Inverse Problems in Pulse-Echo Ultrasound: Exploiting Coherence for Image Enhancement and Quantitative Imaging

Samuel Denys Beuret

Whereas pulse-echo ultrasound imaging relied on focused acoustic waves since its inception, the last two decades have seen the development of techniques based on unfocused waves, including ultrafast ultrasound imaging. In large part due to the emergence of ...

EPFL2024

Smart acoustic lining for UHBR technologies engine: from the design of an electroacoustic metasurface to experimental characterization under flow

Hervé Lissek, Maxime Volery

The SALUTE project aims at evaluating performance of electroacoustic metasurface, employing a surface array of controlled electroacoustic actuators, for smart acoustic lining under grazing turbulent flow to be used in UHBR Technologies Engines. Theoretical ...

Society of Photo-Optical Instrumentation Engineers (SPIE)2023

Combining active and passive acoustic methods to image hydraulic fracture growth in laboratory experiments

Brice Tanguy Alphonse Lecampion, Seyyedmaalek Momeni, Dong Liu

We combine active and passive acoustic measurements to improve the spatio- temporal imaging of hydraulic fracture growth performed under true triaxial confinement in the laboratory. 64 active piezo-electric transducers (54 P waves, 10 S waves) work in sour ...

IOP Publishing2021

Directional Cross-Correlation for Improved Aberration Phase Estimation in Pulse-Echo Speed-of-Sound Imaging

Jean-Philippe Thiran, Samuel Denys Beuret, Simon Canales

There has been a recent surge in methods targeting the recovery of a speed-of-sound map from pulse-echo ultrasound measurements. We focused in this work on a particular technique and identified a drawback shared by similar methods - namely the necessity of ...

IEEE2021

Coordinated Path Planning for Surface Acoustic Beacons for Supporting Underwater Localization

Alcherio Martinoli, Anwar Ahmad Quraishi

Accurate localization is one of the biggest challenges in underwater robotics. The primary reasons behind that are unavailability of satellite-based positioning below the surface, and lack of clear features in natural water bodies for visually aided locali ...

2021

Attenuation of Lamb Modes and SH Waves near cut-off Frequencies

Soumya Yandrapalli

Near cut-off frequencies, the shear horizontal (SH) and Lamb modes in a platelet are created by a bulk acoustic wave bouncing up and down between the platelet sides in an almost vertical direction. The small inclination angle corresponds to slow drift of e ...

IEEE2020

Range-based underwater target localization using an autonomous surface vehicle: Observability analysis

In the field of marine robotics, the problem of range based underwater target localization can be defined as that of localizing an unknown - fixed or moving - target from a surface vehicle called the tracker, using range information available about the tar ...

2018

Optimal acoustic rake receiver

Martin Vetterli, Ivan Dokmanic, Robin Scheibler

An acoustic processing method for M acoustic receivers comprising the steps of: Determining a beamforming weight vector with M weights for the M acoustic receivers based on at least one the steering vector of at least one real acoustic source, on steering ...

2016

Degradation mechanism of slag blended mortars immersed in sodium sulfate solution

Wei Sun, Karen Scrivener

Additions of slag are usually considered to give cementitious materials which perform well in sulfate bearing environments. This paper compares the deterioration of slag cement blends to those of plain Portland cement and demonstrates that this occurs more ...

Pergamon-Elsevier Science Ltd2015

Audio-based Positioning and Target Localization for Swarms of Micro Aerial Vehicles

Meysam Basiri

Swarms of autonomous MAVs show great potential in many diverse applications. In a search and rescue mission, a group of MAVs could quickly reach disaster areas by flying over obstacles, cluttered and inaccessible terrains, and work in parallel to detect an ...

EPFL2015

Scale Model Evaluation and Optimization of Sodar Acoustic Baffles

Fernando Porté Agel

A 21: 1 scaled sodar, operating at 40 kHz, has been built and tested in the laboratory. Sodars, which use sound scattered by turbulence to profile the lowest few hundred meters of the atmosphere, need good acoustic shielding to diminish annoyance and to re ...

American Meteorological Society2015

On the issues related to compliance of LF pulsed exposures with safety standards and guidelines

In this paper, procedures to determine compliance of low-frequency pulsed exposures are investigated. Current methods specified by international standards or guidelines (e.g., from the ICNIRP or IEEE) are recognized to be conservative in order to account f ...

Institute of Physics2013

Threshold Saturation in Spatially Coupled Constraint Satisfaction Problems

Rüdiger Urbanke, Nicolas Macris, Seyed Hamed Hassani

We consider chains of random constraint satisfaction models that are spatially coupled across a finite window along the chain direction. We investigate their phase diagram at zero temperature using the survey propagation formalism and the interpolation met ...

Springer Verlag2013

Electromagnetic characterisation of flexible conductive membranes at millimetre-waves

Julien Perruisseau-Carrier, Herbert Shea, Samuel Rosset, Pietro Romano, Luc Maffli

Presented is the experimental surface impedance characterisation of stretchable conductors at Ka-band, using a non-contact technique based on two-port rectangular waveguide measurements. Two different types of metallisations are analysed, namely gold ion i ...

Institution of Engineering and Technology2013

Assessment of active electroacoustic absorbers as low-frequency modal dampers in rooms

Hervé Lissek, Romain Boulandet, Etienne Thierry Jean-Luc Rivet, Iris Rigas

In small to medium size rooms, natural room modes may severely strengthen the annoyance of low frequency noises, such as traffic or equipment noise. Moreover, there is an actual technological gap in the state-of-the-art concerning low-frequency treatments, ...

2012

Design of Shunt Electric Networks in View of Sound Absorption with Loudspeakers

Hervé Lissek, Romain Boulandet

Variable acoustic properties can be obtained at the diaphragm of a loudspeaker, with the help of very basic control strategies, among which is the simple electrical shunting of the transducer. These shunt techniques have been demonstrated to present singul ...

2011

Electroacoustic absorbers I: bridging a gap between active acoustic feedback control and shunt loudspeakers

Romain Christophe Rémy Fleury, Hervé Lissek, Romain Boulandet

Variable acoustic properties can be obtained at the diaphragm of an electroacoustic transducer, with the help of very basic control strategies, among which is the simple electrical shunting of the transducer. These shunt techniques are compared to active a ...

2011

Electroacoustic absorbers: Bridging the gap between shunt loudspeakers and active sound absorption

Romain Christophe Rémy Fleury, Hervé Lissek, Romain Boulandet

The acoustic impedance at the diaphragm of an electroacoustic transducer can be varied using a range of basic electrical control strategies, amongst which are electrical shunt circuits. These passive shunt techniques are compared to active acoustic feedbac ...

Acoustical Society of America2011

A Probabilistic Measure of Modality Reliability in Speaker Verification

Plamen Prodanov

In this paper, a probabilistic measure for reliability of speaker verification under noisy acoustic conditions is proposed. A Bayesian network is used to estimate a probability for verification errors, given the GMM-based speaker verification system output ...

2005

Calcul stochastique appliqué aux problèmes de détection des signaux aléatoires

Signal detection is one of the basic problems in statistical communication theory, and has many applications to contemporary technology, whether in engineering, medical science, or the environment. The most difficult problems are those involving random sig ...

EPFL1999