Method for dereverberation and noise reduction using spherical microphone arrays

A method for dereverberation and noise reduction is presented. The method is designed for a spherical microphone array, and formulated in the spherical harmonics domain, based on an acoustic model that is also formulated in the spherical harmonics domain. The novelty in the proposed method is the dereverberation process, which exploits the useful formulation in the spherical harmonics domain, which facilitates dereverberation by employing DOA estimation, rather that room impulse response identification. Noise reduction is further performed by a linearly constrained minimum variance filter, where the array output power is minimized with constraint of distortionless response to the direct sound. The paper concludes with a simulation investigation and comparison to theoretical results.