Patent ID: 7970609

Claim:
A method of estimating direction in which a sound source of sound signal is present, the sound signal being inputted to sound signal input units for inputting sound signals from the sound sources present in multiple directions as inputs of multiple channels, comprising the steps of: accepting inputs of multiple channels inputted by the sound signal input units and converting each signal into a signal on a time axis for each channel; transforming the signal of each channel on the time axis into a signal on a frequency axis; calculating a phase component of the transformed signal of each channel on the frequency axis for each identical frequency; calculating phase difference between the multiple channels using the phase component of the signal of each channel, calculated for each identical frequency; calculating an amplitude component of the transformed signal on the frequency axis; estimating an amplitude noise component from the calculated amplitude component; calculating a signal-to-noise ratio for each frequency on the basis of a ratio between the calculated amplitude component and the estimated amplitude noise component; extracting frequencies at which the signal-to-noise ratios are larger than a predetermined value; calculating difference between arrival distances of the sound signal from a target sound source on the basis of the calculated phase difference of the extracted frequencies; and estimating direction in which a target sound source is present on the basis of the calculated difference between the arrival distances.