Frequency invariant beamformer robust against array element mismatch

Abstract

This paper extends the design of frequency invariant beamformer by incorporating robustness in the design formulation to cater for array element mismatches and other non-ideal characteristics. In this approach, a 2-norm constraint on the filter weight is imposed into the design optimization problem. The constraints limit the norm of the beamformer coefficients and thus reduce the sensitivity of the beamformer towards the non-ideal characteristics of the microphones. Design examples and comparisons are presented to illustrate the effectiveness of our approach.