Plenary Lecture
Speech Enhancement Using Bone Conducted Speech
Professor Tetsuya Shimamura
Graduate School of Science and Engineering
Saitama University
Japan
E-mail: shima@sie.ics.saitama-u.ac.jp
Abstract: Speech enhancement techniques are often required in speech processing applications like hands-free communications, hearing aids and speech recognition. During the past few decades, significant progress has been made in the development of speech enhancement algorithms capable of reducing noise. Unfortunately, such noise reduction methods often introduce distortion and the intelligibility is sometimes degraded in severely noisy environments. In this plenary speech, as an old but new technique for speech enhancement, bone-conducted speech is used. 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 can be utilized in a very noisy 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 many cases. 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 significantly improved by combining adequately both the normal and bone-conducted speech signals. The goal of this kind of research is to obtain a clean speech signal 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. He received a Gold Paper Award at IEEE Pacific Rim Conference on Communications, Computers and Signal Processing in 2011.