Beamforming Techniques for Multichannel audio Signal Separation

Beamforming is a signal processing technique. It has been studied in many areas such as radar, sonar, seismology and wireless communications, to name but a few. It can be used for a myriad of purposes, such as detecting the presence of a signal, estimating the direction of arrival, and enhancing a desired signal from its measurements corrupted by noise, competing sources and reverberation. Actually, Beamforming has been adopted by the audio research society, mostly to separate or extract speech for noisy environment. Beamforming techniques basically approach the problem from a spatial point of view. A microphone array is used to form a spatial filter which can extract a signal from a specific direction and reduce the contamination of signals from other directions. In this paper we survey some Beamforming techniques used for multichannel audio signal separation.Comment: 9 pages, 7 Figure

Vector-valued Coherent Risk Measures

We define a coherent risk measures as set-valued maps satisfying some axioms. We show that this definition is a convenient extension of the real-valued risk measures introduced by Artzner, Delbaen, Eber and Heath (1998). We then discuss the aggregation issue, i.e. the passage from valued random portofolio to valued measure of Risk. Necessary and sufficient conditions of coherent aggregation are providedrisk, measures

ROI-BASED RATE CONTROL USING TILES FOR AN HEVC ENCODED VIDEO STREAM OVER A LOSSY NETWORK

International audienceThe growth in the use of high definition (HD) and above video resolutions streams has outstripped the rate at which network infrastructure has been deployed. Video streaming applications require appropriate rate control techniques that make use of the specific characteristics of the video content, such as the regions of interest (ROI). With the introduction of high efficiency video coding (HEVC) streams, we consider new coding features to make a novel ROI-based rate control (RC) algorithm. The proposed approach introduces tiling in a ROI-based rate control scheme. It aims at enhancing the quality of important regions (i.e. faces for a videoconferencing system) considering independently coded regions lying within an ROI and helps evaluating the ROI quality under poor channel conditions. Our work consists of two major steps. First, we designed a RC algorithm based on an independent processing of tiles of different regions. Second, we investigate the effect of ROI-and tile-based rate control algorithm on the decoded quality of the stream transmitted over a lossy channel

De Prague à Tunis, de 1989 à 2011, le rôle de la résistance civile:Entretien avec Abdelwahab Meddeb et Jacques Semelin

Un an après le début de ce qu’on a appelé le Printemps de Tunis, A. Meddeb et J. Sémelin reviennent, au cours d’un entretien, sur la signification des comparaisons avec le Printemps de Prague et les révolutions de velours de 1989 qui s’imposaient alors, en s’interrogeant sur le processus de la résistance civile face aux dictatures

Region-of-interest based rate control scheme for high efficiency video coding

International audienceIn this paper, we propose a new rate control scheme designed for the newest high efficiency video coding (HEVC) standard, and aimed at enhancing the quality of regions of interest (ROI). Our approach allocates a higher bit rate to the region of interest while keeping the global bit rate close to the assigned target value. This algorithm is developed for a videoconferencing system, where the ROIs (typically, faces) are automatically detected and each coding unit is classified in a region of the interest map. This map is given as input to the rate control algorithm and the bit allocation is made accordingly. Experimental results show that the proposed scheme achieves accurate target bit rates and provides an improvement in the region of interest quality, both in objective metrics and based on subjective quality evaluation

Modern approach to infectious disease management using infrared thermal camera scanning for fever in healthcare settings.

International audienceWe conducted a prospective study to assess the value of the use of infrared thermal cameras in detecting fevers in both patients and healthcare workers between May 2015 and February 2016 in a university hospital center in Southern France