Efficient artifacts filter by density-based clustering in long term 3D whale passive acoustic monitoring with five hydrophones fixed under an Autonomous Surface Vehicle

International audiencePassive underwater acoustics allows for the monitoring of the echolocation clicks of cetaceans. Static hydrophone arrays monitor from a fixed location, however, they cannot track animals over long distances. More flexibility can be achieved by mounting hydrophones on a mobile structure. In this paper, we present the design of a small non-uniform array of five hydrophones mounted directly under the Autonomous Surface Vehicle (ASV) Sphyrna (also called an Autonomous Laboratory Vehicle) built by SeaProven in France. This configuration is made challenging by the 40cm aperture of the hydrophone array, extending only two meters below the surface and above the thermocline, thus presenting various artifacts. The array, fixed under the keel of the drone, is numerically stabilized in yaw and roll using the drone's Motion Processing Unit (MPU). To increase the accuracy of the 3D tracking computed from a four hour recording of a Sperm Whale diving several kilometers away, we propose an efficient joint filtering of the clicks in the Time Delay of Arrival (TDoA) space. We show how the DBSCAN algorithm efficiently removes any outlier detection among the thousands of transients, and yields to coherent high definition 3D tracks

Représentation neuronale des mélanges odorants dans le bulbe olfactif des mammifères

GRENOBLE1-BU Sciences (384212103) / SudocGRENOBLE INP-Phelma (381852301) / SudocSudocFranceF

Multiple sources real-time tracking using transitivity constraints

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Whale cocktail party: real-time multiple tracking and signal analyses

ABSTRACT This paper provides a real-time passive underwater acoustic method to track multiple emitting whales using four or more omni-directional widely-spaced bottom-mounted hydrophones. Since the interest in marine mammals has increased, robust and real-time systems are required. To meet these demands, a real-time multiple tracking algorithm is developed. After a non parametric Teager-Kaiser-Mallat signal filtering, rough Time Delays Of Arrival are calculated, selected and filtered, and used to estimate the positions of whales for a constant, linear sound speed profile or an estimated. The complete algorithm is tested on real data from the NUWC 1 and the AUTEC 2 . Our model is validated by similar results from the US Navy 3 and SOEST 4 Hawaii univ labs in the case of one whale, and by similar whales counting from the Columbia univ. ROSA 5 lab in the case of multiple whales. At this time, our tracking method is the only one giving typical speed and depth estimations for multiple emitting whales. RESUME Ce papier propose une méthode temps-réel de trajectographie par acoustique passive de plusieurs cétacés émet-tant simultanément en utilisant un réseau d'au moins 4 hydrophones espacés de quelques centaines de mètres. Etant donné l'intérêt accru pour les mammifères marins, des systèmes temps-réel et robustes sont nécessaires. Pour répon-dre à cette demande, un algorithme temps-réel de trajectographie multiple a été développé. Après un filtrage non paramétrique Teager-Kaiser-Mallat du signal, les différences de temps d'arrivée aux hydrophones sont estimées, selectionnées, filtrées, et permettent d'estimer les positions des baleines pour un profil de célérité constant, linéaire ou estimé. L'algorithme est testé sur des données réelles du NUWC 1 et de l'AUTEC 2 . Notre modèle est validé par des résultats similaires de l'US Navy 3 et du laboratoire SOEST 4 de l'université d'Hawaii dans le cas d'émissions simples, et par une estimation du nombre de baleines du laboratoire ROSA 5 de l'université de Columbia dans le cas de plusieurs émissions simultanées. Actuellement, notre méthode de trajectographie est la seule donnant, dans le cas de plusieurs baleines, des vitesses et des profondeurs vraisemblables

Procédé de trajectographie en temps réel sur ordinateur portable, de plusieurs cétacés par acoustique passive

numéro 07/06162no abstrac

Approximation of Linear Fisher Discriminant Analysis for Adaptive Word Dependent Visual Feature Sets Improving Image Auto-annotation

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Contraintes conjointes de différences temporelles et effet Doppler multibandes pour la séparation, caractérisation et localisation de sources sonores par acoustique passive

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Strategy for a statistical analysis of odour influence on the mammalian olfactory bulb responsiveness

This paper proposes a global strategy for statistical analysis of odour influence on the responsiveness of the mammalian olfactory bulb, the first relay of the olfactory pathway. Experiments were performed on 86 mitral cells recorded in 17 anaesthetized freely breathing rats. Five pure odours and their binary mixture were used. The spontaneous activity and odour-evoked responses of the cells were characterized by their temporal distribution of activity along the respiratory cycle, i.e. by cycle-triggered histograms. Several statistical analyses were performed to describe the influence of binary odour mixtures and, especially, to detect a possible dominance of one component of the mixture.Olfaction, odour responses, statistical analyses, temporal patterns, response comparison,