Reproduction of human-phonatory radiation characteristics with a polyhedron loudspeaker
Naoki Yoshimoto, Masanori Morise, Takanobu Nishiura · The Journal of the Acoustical Society of America · 2012
Spoken dialogue systems have been studied for car navigation systems and voice search systems. For evaluation, a loudspeaker is used instead of a human because these systems require various kinds of speech samples. However, the sounds radiated by loudspeaker can not reproduce human-phonatory radiation characteristics. Therefore, the mouth simulator is utilized to reproduce human-phonatory radiation characteristics. Although it is based on the average mouth shape, shapes of mouth are different among phonemes. Therefore, due to the hardware structure, it can not accurately reproduce various human-phonatory radiation characteristics affected by shapes of mouth. In this study, we developed a polyhedron loudspeaker to solve this problem. It consists of eleven loudspeakers which are independently controlled. Controlling eleven loudspeakers makes it possible to reproduce desired radiation characteristics. Besides, we try to reproduce human-phonatory radiation characteristics of each Japanese five vowel with an adaptive algorithm based on the MINT (Multi-input/output INverse Theorem). We carried out an experiment to verify the effectiveness of the proposed method. As a result, it was confirmed that phonatory radiation characteristics of Japanese five vowels could be accurately approximated compared with the mouth simulator.