On optimization of broadband beamformer for hearing aid applications

This paper considers various wideband signal model optimization techniques and associated performance results using steerable fixed beam microphone array processing for hearing aid applications in free-space and reverberant conditions. We first review and compare various conventional broadband and narrowband array optimization techniques. Then new results on maximum energy criterion broadband array optimization formulated for subband processing are presented. The uniformly spaced subband and the nonuniformly spaced subband using quadrature mirror filter approaches are treated. Then algorithms for implementing the hearing aid´s search mode based on direction-of-arrival (DOA) estimation techniques for acoustic signals using subspace methods are discussed. Finally, various simulation results under the maximum energy criterion and DOA estimation for free-space and reverberant conditions are presented to demonstrate the feasibility of the proposed techniques