Signalverarbeitung

Signalverarbeitung für Mikrofonarrays

A microphone array is an arrangement of at least two microphones (we use an arrangement of up to 16 microphones). By suitable processing of the sensor signals a directivity can be achieved. If the maximum of this directional response is steered towards a speaker in a room, noise signals impinging from other directions are suppressed. In contrast to conventional directional microphones, which have to be aligned mechanically, the directivity of an array can be steered by processing the output signals of each of its microphones. By including algorithms for speech detection and speaker localization in the microphone array system, the directivity can be focussed automatically on a speaker. Further improvement of the signal-to-noise ratio can be achieved by employing noise reduction procedures such as the noise-cancelling or the spectral-subtraction method. Possible applications for microphone arrays are teleconferencing or speech transmission in auditoria. (key words: microphone array, digital signal processing, directional pattern, noise reduction, speech detection, speaker localization)