Noise Robust Speech Recognition Using Multi-Channel Based Channel Selection And ChannelWeighting
This work addresses noise robustness in speech recognition for applications in noisy environments, presenting an incremental improvement over existing methods.
The paper tackled robust automatic speech recognition in noisy conditions by proposing channel selection and weighting methods, with channel weighting significantly outperforming channel selection and performing equally well or better than MVDR beamforming on real test data.
In this paper, we study several microphone channel selection and weighting methods for robust automatic speech recognition (ASR) in noisy conditions. For channel selection, we investigate two methods based on the maximum likelihood (ML) criterion and minimum autoencoder reconstruction criterion, respectively. For channel weighting, we produce enhanced log Mel filterbank coefficients as a weighted sum of the coefficients of all channels. The weights of the channels are estimated by using the ML criterion with constraints. We evaluate the proposed methods on the CHiME-3 noisy ASR task. Experiments show that channel weighting significantly outperforms channel selection due to its higher flexibility. Furthermore, on real test data in which different channels have different gains of the target signal, the channel weighting method performs equally well or better than the MVDR beamforming, despite the fact that the channel weighting does not make use of the phase delay information which is normally used in beamforming.