This paper describes a spatial spectral subtraction method by using the complementary beamforming microphone array to enhance noisy speech signals for speech recognition. The complementary beamforming is based on two types of beamformers de-signed to obtain complementary directivity patterns with respect to each other. In this paper, it is shown that the nonlinear subtraction processing with complementary beamforming can result in a kind the spectral subtraction without the need for speech pause detection. To evaluate the effectiveness, speech enhancement exper-iments and speech recognition experiments are performed based on computer simulations under both stationary and nonstationary noise conditions. In comparison with the optimized conventional delay-and-sum array, it is shown that: (1) the proposed array performs more than 20% better in word recognition rates under the conditions that the white Gaussian noise is used, (2) the proposed array improves the word recognition rate by about 5% when the interfering noise is a single speaker or the overlap of some speakers, (3) the proposed array improves the word recognition rate by more than 10% when the noise is a nonstationary bubble noise.
Cite as: Saruwatari, H., Kajita, S., Takeda, K., Itakura, F. (1999) Speech enhancement using nonlinear microphone array under nonstationary noise conditions. Proc. 6th European Conference on Speech Communication and Technology (Eurospeech 1999), 2567-2570, doi: 10.21437/Eurospeech.1999-564
@inproceedings{saruwatari99_eurospeech,
author={Hiroshi Saruwatari and Shoji Kajita and Kazuya Takeda and Fumitada Itakura},
title={{Speech enhancement using nonlinear microphone array under nonstationary noise conditions}},
year=1999,
booktitle={Proc. 6th European Conference on Speech Communication and Technology (Eurospeech 1999)},
pages={2567--2570},
doi={10.21437/Eurospeech.1999-564}
}