Hemispherical microphone arrays for sound capture and beamforming

We design and demonstrate a hemispherical microphone array for spatial sound acquisition and beamforming. Our design makes use of the acoustic image principle. It is especially appropriate for a half 3D acoustic environment where all sound sources are constrained on one side of a rigid plane. It avoids the difficulties of building a full spherical microphone array yet keeps the advantage of achieving a direction-invariant beampattern. A special microphone layout is designed for simple implementation. We also propose an approach to effectively calibrate data-independent coefficients of the system. Simulation and experimental results are presented.