Microphone arrays based on the minimum variance distortionless response

(MVDR) beamformer are among the most popular for speech

enhancement applications. The original MVDR is excessively sensitive

to source location and microphone gains. Previous research has

made MVDR practical by successfully increasing the robustness of

MVDR to source location, and MVDR-based microphone arrays are

already commercially available. Nevertheless, MVDR performance

is still weak in cases where microphone gain variations are too large,

e.g., for circular arrays of directional microphones. In this paper we

propose an improved MVDR beamformer which takes into account

the effect of sensors (e.g. microphones) with arbitrary, potentially

directional responses. Specifically, we form estimates of the relative

magnitude responses of the sensors based on the data received at the

array and include those in the original formulation of the MVDR

beamforming problem. Experimental results on real-world audio

data show an average 2.4 dB improvement over conventional MVDR

beamforming, which does not account for the magnitude responses

of the sensors.

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In  ICME

Publisher  IEEE

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