2013 Volume 34 Issue 3 Pages 197-205
In a number of engineering fields, information on the distance to the target is very important. We previously proposed an acoustic distance measurement method based on interference between the transmitted and reflected waves, which can be used for distance measurement over a short range. The previously proposed method requires equipment such as a loudspeaker and a microphone for cancellation processing of background components due to the spectrum of the transmitted wave and the transfer function of the measurement system in real environments. Therefore, in the previously proposed method, a sound source of the transmitted wave must be known in advance. In the present paper, we propose a new acoustic distance measurement method based on phase interference obtained using the cross-spectral method with stereo microphones, which does not require the condition that a sound source of the transmitted wave is known. The conventional cross-spectral method requires a measuring remote microphone and a reference microphone to be placed near a loudspeaker, meanwhile the proposed method requires stereo microphones to be placed near a sound source. Finally, we confirmed the validity and effectiveness of the newly proposed method through computer simulations and evaluation experiments in real environments.