Robust frequency invariant beamformer design using variably-weighted constrained least squares

It is of practical interest to design frequency invariant beamformers (FIBs) for distortionless wideband acoustic signal acquisition using microphone arrays. It has been shown that the conventional FIBs are usually highly sensitive to microphone mismatches, such as microphone gain and phase errors. Recently, a robust FIB design approach using constrained least squares criterion has been proposed. However, the problem with the robust FIB design is that the performance will degrade when the design bandwidth is increasing. To combat this problem, a robust FIB design approach using the variably-weighted constrained least squares is proposed in this paper. Several design examples are presented to show the problem with the existing design approach and to demonstrate the superior performance of the proposed design approach.