ROBUST BROADBAND BEAMFORMING FOR MICROPHONE ARRAYS

Abstract

A microphone array consists of multiple microphones placed at different spatial locations. Built upon knowledge of sound propagation principles, the multiple inputs can be manipulated to enhance or attenuate signals emanating from particular directions. In this way, microphone arrays provide a means of enhancing a desired signal in the presence of corrupting noise sources. Moreover, this enhancement is based purely on knowledge of the source location, and so microphone array techniques are applicable to a wide variety of noise types. . Microphone arrays can also be used to find the location of the source and automatically steer the array in that direction. So they have great potential in practical applications of speech processing, due to their ability to provide both noise robustness and hands-free signal acquisition. This thesis aims to design a broadband beamformer using the arrays of microphone which has the potential to enhance the signal coming from desired direction by reducing the effect of noise and other interference present in the signal. The beamformer should also have flat frequency response and is robust against erroneous microphones. In this thesis various robust algorithms are discussed and combined with beamforming algorithms with an objective to achieve a better beamformer frequency response when implemented with non-omnidirectional microphones