On the robust near-field broadband beamformer design

Broadband microphone arrays play an important role for noise reduction in various applications, such as voice interface equipment or hands-free telephony. For most cases, it is essential to design the beamformer so that certain spatial and frequency features can be extracted and the rest being attenuated. For the method to be data-independent, a physical signal propagation model can be deployed and the optimization problem can be posed. In this paper, this design problem is studied. Robust minimax designs are considered. We will study the sensitivity of the designs towards uncertainties in the parameters, including speaker positions and microphone locations. We found that the optimal design is not very sensitive to speaker position perturbations, but is affected significantly if microphone locations are indeed erroneous.