Interfacing speech recognition an vision guided microphone array technologies

Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2003.Includes bibliographical references (p. 57-58).One goal of a pervasive computing environment is to allow the user to interact with the environment in an easy and natural manner. The use of spoken commands, as inputs to a speech recognition system, is one such way to naturally interact with the environment. In challenging acoustic environments, microphone arrays can improve the quality of the input audio signal by beamforming, or steering, to the location of the speaker of interest. The existence of multiple speakers, large interfering signals and/or reverberations or reflections in the audio signal(s) requires the use of advanced beamforming techniques which attempt to separate the target audio from the mixed signal received at the microphone array. In this thesis I present and evaluate a method of modeling reverberations as separate anechoic interfering sources emanating from fixed locations. This acoustic modelling technique allows for tracking of acoustic changes in the environment, such as those caused by speaker motion.by Vibhav Shyam Rangarajan.M.Eng