Journal of the Institute of Electronics Engineers of Korea SP (대한전자공학회논문지SP)

The Institute of Electronics and Information Engineers (대한전자공학회)
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A simulation study of speech perception enhancement for cochlear implant patients using companding in noisy environment

잡음 환경에서 압신을 이용한 인공 와우 환자의 언어 인지 향상 시뮬레이션 연구

  • Lee Young-Woo (Dept. of Biomedical Engineering, Hanyang University) ;
  • Ji Yoon-Sang (Dept. of Biomedical Engineering, Hanyang University) ;
  • Lee Jong-Shil (Dept. of Biomedical Engineering, Hanyang University) ;
  • Kim In-Young (Dept. of Biomedical Engineering, Hanyang University) ;
  • Kim Sun-I. (Dept. of Biomedical Engineering, Hanyang University) ;
  • Hong Sung-Hwa (Dept. of Otolaryngology-Head and Neck Surgery, Sungkyunkwan University of Medicine) ;
  • Lee Sang-Min (School of Electrical Engineering, Inha University)
  • 이영우 (한양대학교 의공학교실) ;
  • 지윤상 (한양대학교 의공학교실) ;
  • 이종실 (한양대학교 의공학교실) ;
  • 김인영 (한양대학교 의공학교실) ;
  • 김선일 (한양대학교 의공학교실) ;
  • 홍성화 (성균관대학교 의과대학 이비인후과) ;
  • 이상민 (인하대학교 전자전기공학부)
  • Published : 2006.09.01
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Abstract

In this study, we evaluated the performance of a companding strategy as a preprocessing for speech enhancement and noise reduction. The proposed algorithm is based on two tone suppression that is human's hearing characteristics. This algorithm enhances spectral peak of speech signal and reduces background noise, however it has tradeoff characteristics between speech distortion and noise reduction due to limited channel number and nonlinear block. Therefore, we designed two different companding structures that have relative characteristics of noise reduction and speech distortion and found suitable companding structures by difference of individual speech perception ability in noise environment. Thus we proposed speech perception enhancement of cochlear implant user in noise environment with low SNR. The performance of the proposed algorithm was evaluated through 5 normal hearing listeners using noise band simulation. Improvement of speech perception was observed for all subjects and each subject preferred the different type of companding structure.

본 연구에서 인공 와우 환자의 잡음 상황에서 음성 신호 강조와 잡음 제거를 위한 전 처리로서 companding strategy를 적용하고 이를 평가하였다. Companding은 인간의 청각 특성인 two tone suppression에 기반하며 이는 음성 스펙트럼 피크를 강화하고 배경 잡음을 감소시킨다. 하지만 companding은 잡음 제거와 스펙트럼 피크의 강화에 효과적인 반면, 제한된 채널의 수와 비선형 블록으로 인한 음성 정보 손실의 교환 특성을 가진다. 따라서 본 연구에서는 잡음 제거와 음성 정보 손실의 정도가 상대적인 두 companding 구조를 설계하여 개인마다 잡음 상황에서 언어 인지 특성차이에 따른 적절한 필터 뱅크를 도출하였으며, 낮은 신호 대 잡음 비 환경에서 인공 와우 환자의 언어 인지 향상을 위한 방법을 제시하였다. 제안된 알고리즘은 잡음 밴드 시뮬레이션을 이용하여 정상인 5명에게 평가되었다. 모든 피실험자에게서 효과적인 언어 인지의 향상이 관측되었고, 각 피실험자가 선호하는 필터 뱅크는 다르게 나타났다.

Keywords

References

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