クロススペクトル法を用いた位相干渉に基づく音響測距システムの一実現

抄録

The distance to a target is basic information in many engineering fields. As is generally known, the distance is typically estimated using time-of-flight (TOF) between transmitted and reflected impulses. However, it cannot be estimated in a close range where the reflected waves are buried in the transmitted wave. For distance estimation of close range targets using acoustic signals, we have proposed a method based on the phase interference between transmitted and reflected waves. In addition, by using cross-spectral method, we have proposed a method to remove the effect of the measuring system which is composed of loudspeaker, microphone, amplifiers and so on. Moreover, this method can also utilize environmental sound such as music and speech with arbitrary frequency spectrum as a transmitted sound besides a band-limited impulse sound. This paper describes a prototype system realizing this method by implementing it into a microcomputer system and confirms the result of experiment in actual sound field using music sound source.