Robust speech recognition using near-field superdirective beamforming with post-filtering

This paper assesses the effectiveness of a microphone array system in providing robust hands-free speech recognition on a computer workstation. Near-field superdirectivity (NFSD) is used for the beamforming, and the effect of adding a post-filter is investigated. In the experiments, the speaker is located directly in front of the computer monitor at a distance of 60 cm and the array is designed to fit across the top of a standard 17 inch monitor. To test the proposed system, connected digit strings from the TIDIGITS database are used. The array is shown to have a marked effect on the recognition results in a high noise office environment, particularly where there is a high level of undesired speech.