Stepwise Phase Difference Restoration Method for Sound Source Localization using Multiple Microphone Pairs

We propose a new methodology of sound source localization named SPIRE (stepwise phase difference restoration) that is able to localize sources even if they are neighboring in a reverberant environment. Localizing sound sources in reverberant environments is difficult, because the variance of the direction of an estimated sound source increases in reverberant environments. The major feature of our proposed method is restoration of a microphone pair's phase difference (M1) by using the phase difference of another microphone pair (M2) under the condition that the distance between MTs microphones is longer than the distance between M2's microphones. This restoration process makes it possible to reduce the variance of an estimated sound source direction and to solve the spatial aliasing problem that occurs with the M1's phase difference. The experimental results in a reverberant environment (reverberation time=about 300 ms) indicate that our proposed method can localize sources even if they are neighboring (even if the difference in the sources' directions equals 10 degree).