Multi Channel Sub Band Wiener Beamformer

Sammanfattning: With the recent advance in microphone array speech processing, achieving robustness of speaker localization becomes most significant aspect. At the same time considerable research growth is performed in developing the multiple microphone sensors equipped rooms are developed also called as smart rooms for real time applications. The accuracy of speaker localization is down casted by acoustic noise and room reverberations. In distributed meeting environment speaker localization is performed by far field microphone arrays with the help of beamforming. But far field Microphone performance is degraded by room reverberations and acoustic noise. In this master thesis, speaker localization with two adaptive beamforming techniques in distributed meeting application in reverberated environment with the help of far filed microphone arrays is design and implemented. The two beamforming methods examined are multichannel wiener beamformer and multichannel sub band wiener beamformer. These methods use wiener filtering technique for their implementation and they are implemented to capture the human voice using widely separated microphone arrays even when irregular disturbances are present. A smart room is developed with Image source model for generating reverberation in which beamformers are implemented. In sub band beamformer WOLA filter bank is designed. The sub band beamforming is further extended to steered response power with phase transform for speaker localization is achieved with the cross correlation but speech is heavily degraded by the noise which can be further studied to eliminated it. Finally the quality of the speech is tested using SNR and PESQ (Perceptual Evaluation of Speech Quality) and also the performance of the system with respect to reverberation time is calculated. The results show that the two implementations are acceptable in terms of PESQ score.