Plenary Lecture

Plenary Lecture

Toward Speech Communication in Highly Noisy Environments Using Bone Conduction

Professor Tetsuya Shimamura
Saitama University
Saitama City, Japan


Abstract: The transmission of voice on bones is called bone conduction. When the voice waveforms are transmitted from the voice source (vocal cord) through the vocal tract wall and skull, they do not confront directly with noise. This is the reason why the bone-conducted speech signal is utilized to accomplish speech communications in a very noisy environment. Recently it was reported that bone-conducted speech could be effectively used for speech recognition and speaker recognition even in a negative decibel signal-to-noise ratio environment. However, normally it is known that the quality of bone-conducted speech is comparatively lower than that of normal speech being transmitted through air. This may be caused by the fact that the frequency components more than 1[kHz] deteriorate in bone-conducted speech. A straightforward method to improve the quality of bone-conducted speech is to emphasize the high frequency components. However, this has been not accepted in current communication systems. One of the reasons of this fact may be that the phenomenon of bone conduction is speaker dependent. Thus, in this plenary speech, as a speaker-dependent technique, the use of an air- and bone-conduction integrated microphone is mainly discussed. Also, it is presented that the quality of bone-conducted speech can be improved by utilizing both long-term spectra of the normal and bone-conducted speech signals. On the other hand, it is set out to design a reconstruction filter for the speaker only from the bone-conducted speech. This is a hot topic in the field of bone conducted speech. The goal of this kind of research is to accomplish a smooth speech communication in highly noisy environments.

Brief Biography of the Speaker:
Tetsuya Shimamura received the B.E., M.E., and Ph. D. degrees in electrical engineering from Keio University, Yokohama, Japan, in 1986, 1988, and 1991, respectively. In 1991, he joined Saitama University, Saitama City, Japan, where he is currently a Professor. During this, he joined Loughborough University, UK, and The Queen's University of Belfast, UK, in 1995 and 1996, respectively, as a visiting Professor. He is an author or co-author of 6 books, and member of the organizing committee of several international conferences. His interests are in digital signal processing and its applications to speech, image and communication systems.



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