Enhancement of Speech Intelligibility using Beamforming Techniques

Abstract: Speech enhancement is a process of enhancing the intelligibility or quality of speech using various audio processing algorithms. The concept of speech enhancement is the most important field for many applications such as teleconferencing systems, speech recognition, VoIP, mobile phones, hearing aids, etc. [1]. The delight of the speech enhancement algorithms using single microphone was tamed and sooner the markets will be dominated by microphone arrays with beamforming techniques in which significantly high signal to noise ratios (SNR) are observed. A considerable amount of research has already been done about the feasibility and advantages of using microphone arrays. Several beamforming techniques are widely applied by researchers round the globe. In this thesis, eight selective beamforming techniques have been applied to enhance the intelligibility of speech degraded by interference. In order to demonstrate the algorithms, a graphical user interface (GUI) has been developed in matlab, where user has a chance to select the number of sensors in the linear array and the spacing between them, source and interference directions, type of algorithm and so on. Also, user can compare all the Beamformers by keeping a default environment. The performances are measured in terms of signal to noise ratio (SNR), speech and noise distortions and ITU-T’s PESQ values. This thesis describes the opportunities and constraints for application of eight beamforming techniques using linear microphone arrays.