Distributed microphone array networks for bioacoustic monitoring applications
A compact microphone array is an essential tool for capturing a sound field and analyzing it: the number, power and location of acoustic sources are among the information that can be analyzed. Applications are then envisaged for monitoring natural environments: detection, localization, species counting. However, the use of a single microphone array has limitations in terms of resolution, solid angle of analysis and separation between the direct sound and its reflections. Although the trend towards increasing and densifying the number of microphones increases the accuracy and resolution of the analysis, implementing such a strategy can be cumbersome and costly. An alternative strategy is to use a distributed network of compact microphone arrays. By multiplying the points of view for analysis, ambiguities can be removed, such as the number of sources. The spatial resolution can be increased, the sources positions can be retrieved and the area covered by the network can be larger than with a single microphone array. However, the signal processing associated with this microphone arrays network remains a complex topic, and will be the research theme of this post-doctoral contract. The goal is to provide a monitoring system which outputs a set of signals corresponding to sound events, along with their position and date of emission. This system will enable information to be compressed in relation to hours of raw recordings to be processed. It will enable the classification of sound events and analysis of the soundscape for bioacoustic monitoring. Algorithms derived from recent advances in navigation for virtual reality could be a starting point. A scanning area of a few hundred square meters is envisaged, which will require a necessary adaptation to this change of scale compared with virtual reality applications (a few square meters). A laboratory demonstrator will be developed based on synthesized soundscapes, and experimental fields may also be set up in natural environments.
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