Acoustic distance measurement method measurable from zero meters based on the interference between transmitted and reflected waves using power and phase spectra of single channel observations

Since the distance to target is very important information, we have proposed an acoustic distance measurement using a standing wave, which is generated by interference between transmitted and reflected waves. This method is given in a very simple form such that the distance between microphone and target is estimated as a peak value of the range spectrum (i.e., the absolute value of Fourier transform with respect to the power spectrum of the observed wave). However, to measure the short distance, the wide bandwidth of the transmitted wave is required. This paper describes a new distance estimation method measurable from 0 m based on the interference between transmitted and reflected audible sound, especially using only a single microphone (i.e., single channel observations). More concretely, we introduce an analytic signal instead of the power spectrum and examine the validity and effectiveness of our method through computer simulation and by applying it to an actual sound field with a band-limited impulse sound.