A Minimum variance beamformer for spatially distributed microphones using a soft reference selection

The signal quality at different microphone locations varies for distributed microphone arrays. Such microphone constellations require a suitable beamformer design that considers these differences in the input signal conditions. In this paper a frequency domain minimum variance (MV) beamforming approach is presented that uses a soft reference selection. The filter coefficients of this MV beamformer only depend on the spatial correlation properties of the input signals. The proposed beamformer is able to partially equalize the acoustic system, i.e. the magnitude of the overall transfer function is the envelope of all acoustic transfer functions.