Robust continuous speech recognition system based on a microphone array

A robust speech recognition system for videoconference applications is presented based on a microphone array. By means of a microphone array, the speech recognition system is able to know the position of the users and increase the signal-to-noise ratio (SNR) between the desired speaker signal and the interference from the other users. The user positions are estimated by means of the combination of a direction of arrival (DOA) estimation method with a speaker identification system. The beamforming is performed by using the spatial references of the desired speaker and the interference locations. A minimum variance algorithm with spatial constraints working in the frequency domain is used to design the weights of the broadband microphone array. Results of the speech recognition system are reported in a simulated environment with several users asking questions to a geographic data base