Microphone array speech recognition: experiments on overlapping speech in meetings

This paper investigates the use of microphone arrays to acquire and recognise speech in meetings. Meetings pose several interesting problems for speech processing, as they consist of multiple competing speakers within a small space, typically around a table. Due to their ability to provide hands-free acquisition and directional discrimination, microphone arrays present a potential alternative to close-talking microphones in such an application. We first propose an appropriate microphone array geometry and improved processing technique for this scenario, paying particular attention to speaker separation during possible overlap segments. Data collection of a small vocabulary speech recognition corpus (Numbers) was performed in a real meeting room for a single speaker, and several overlapping speech scenarios. In speech recognition experiments on the acquired database, the performance of the microphone array system is compared to that of a close-talking lapel microphone, and a single table-top microphone.