| Project/Area Number |
05452333
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Otorhinolaryngology
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
SONE Toshio Tohoku Univ., R.I.E.C., Professor, 電気通信研究所, 教授 (50005245)
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| Co-Investigator(Kenkyū-buntansha) |
KOBAYASHI T Tohoku Univ., School of Medicine, Associate Professor, 医学部, 助教授 (80133958)
TAKASAKA T Tohoku Univ., School of Medicine, Professor, 医学部, 教授 (80004646)
OZAWA K Tohoku Univ., R.I.E.C., Research Associate, 電気通信研究所, 助手 (30204192)
ASANO F Tohoku Univ., R.I.E.C., Research Associate, 電気通信研究所, 助手 (00231895)
SUZUKI Y Tohoku Univ., R.I.E.C., Associate Professor, 電気通信研究所, 助教授 (20143034)
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| Project Period (FY) |
1993 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥5,500,000 (Direct Cost: ¥5,500,000)
Fiscal Year 1994: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1993: ¥4,700,000 (Direct Cost: ¥4,700,000)
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| Keywords | Digital Hearing Aid / Noise Reduction / Howling Suppression / Adaptive Microphone Array / Adaptive Feedback Canceler / Speech Intelligibility / ハウリング / ディジタル信号処理 / 補聴器 / RLSアルゴリズム / 仮想相関行列法 / 音声強調 / 周波数圧縮 / 適応ノッチフィルタ |
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| Research Abstract |
1. Algorithm for noise reduction An algorithm for reducing stationary/nonstationary environmental noise has been developed and has been verified via computer simulation. Moreover, total noise reduction system has been constructed using signal processing system. For ebvironmental noise reduction, an adaptive beamforming technique was combined with conventional fixed beamformer to obtain robust attenuation for not only stationary noise but also nonstationary noise. On the other hand, for reducing howling, adaptive feedback canceler was introduced.
2. Evaluation The system developed has been applied to real environmental noise and was evaluated in terms of the amount of noise reduction and other issues. The results can be summarized as follows : As for the environmental noise, directional noise with large power was reduced by more than 20 dB,while nondirectional noise such as reverberation is also reduced by 10 dB.As for the howling, howling margin increased by 20 dB.
3. Improvement in Speech Intelligibility Noise reduction system has been applied to the speech corrupted by noise, and the listening test was conducted. The results can be summarized as follows : As for the environmental noise reduction, the speech intelligibility was improved from 50 % to 70 % by introducing the proposed system. As for the howling cancellation, periodic signals such as voiced speech is corrupted by the conventional adaptive feedback canceler. However, use of frequency compressor together with adaptive feedback canceler as proposed in our system yields little corruption and no effect on speech intelligibility.
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