Robust microphone array using subband adaptive beamformer and spectral subtraction

This paper presents a new robust microphone array to enhance speech signal under the influence of noise and jammer(s). The proposed structure comprises of a soft constrained subband beamformer, a blocking system and a non-coherent processing technique. The soft constrained beamformer enhances the desired speech signal in a specified region by suppressing all side-lobes. This enhanced signal is then used as a reference signal by the blocking system to estimate the interference spectrum. Finally, the beamformer's output is spectral subtracted using the estimated interference spectrum. Simulations in a real office environment show higher interference suppression level compared to those obtained using the soft constrained beamformer only. Most importantly. this is achieved with negligible expense on target signal distortion.