8th European Conference on Speech Communication and Technology

Geneva, Switzerland
September 1-4, 2003


CFA-BF: A Novel Combined Fixed/Adaptive Beamforming for Robust Speech Recognition in Real Car Environments

Xianxian Zhang, John H.L. Hansen

University of Colorado at Boulder, USA

Among a number of studies which have investigated various speech enhancement and processing schemes for in-vehicle speech systems, the delay-and-sum beamforming (DASB) and adaptive beamforming are two typical methods that both have their advantages and disadvantages. In this paper, we propose a novel combined fixed/adaptive beamforming solution (CFABF) based on previous work for speech enhancement and recognition in real moving car environments, which seeks to take advantage of both methods. The working scheme of CFABF consists of two steps: source location calibration and target signal enhancement. The first step is to pre-record the transfer functions between speaker and microphone array from different potential source positions using adaptive beamforming under quiet environments; and the second step is to use this pre-recorded information to enhance the desired speech when the car is running on the road. An evaluation using extensive actual car speech data from the CU-Move Corpus shows that the method can decrease WER for speech recognition by up to 30% over a single channel scenario.

Full Paper

Bibliographic reference.  Zhang, Xianxian / Hansen, John H.L. (2003): "CFA-BF: a novel combined fixed/adaptive beamforming for robust speech recognition in real car environments", In EUROSPEECH-2003, 1289-1292.