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Microphone Array Post-Processor Using Instanteneous Direction of Arrival
  • Ivan Tashev, (Microsoft Research)
  • Alex Acero, (Microsoft Research)
  • Microphone arrays and array signal processing
  • Noise reduction techniques
  • Sound enhancement and sound separation
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In this paper we describe a novel algorithm for post-processing a microphone array's beamformer output to achieve better spatial filtering under noise and reverberation. For each audio frame and frequency bin the algorithm esti-mates the spatial probability for sound source presence and applies a spatio-temporal filter towards the look-up direction. It is implemented as a real-time post-processor after a time-invariant beamformer and it substantially improves the direc-tivity of the microphone array. The algorithm is CPU efficient and adapts quickly when the listening direction changes. It was evaluated with a linear four element microphone array. The directivity index improvement is up to 8 dB, the suppres-sion of a jammer 40° from the sound source is up to 17 dB.

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Edition : Télécom Paris -- 2006