SOUND SOURCE DISTANCE MEASURING DEVICE, ACOUSTIC DIRECT/INDIRECT RATIO ESTIMATION DEVICE, NOISE REMOVAL APPARATUS, METHODS FOR THESE AND PROGRAM

摘要

PROBLEM TO BE SOLVED: To accurately obtain a direct/indirect ratio estimate of an acoustic signal.SOLUTION: A sound source distance measuring device uses a frequency domain signal obtained by converting a received-sound signal for a sound received by multiple microphones into a frequency domain to obtain a power estimate of the frequency domain signal. The device obtains a power estimate of a direct sound suppressing signal obtained by applying processing of suppressing a signal component coming from a direct sound source direction to the frequency domain signal, or obtains the power estimate of the direct sound suppressing signal obtained by converting a signal, which is obtained by applying the processing of suppressing the signal component coming from the direct sound source direction to the received-sound signal, into a frequency domain. The device uses a directivity shape correction factor obtained from a function showing a directivity characteristic of suppressing the signal component coming from the direct sound source direction to correct the power estimate of the direct sound suppressing signal and to obtain a power estimate of an indirect sound, and the device uses both power estimates of the frequency domain signal and the indirect sound to obtain a direct/indirect ratio estimate that shows a proportion of the power estimate of the direct sound to the power estimate of the indirect sound.