An apparatus for recognizing a sound source, the apparatus comprising:
- at least four acoustic sensors configured to detect acoustic signals, each of the acoustic sensors detecting the acoustic signals from air, wherein four of the acoustic sensors are arranged at vertices A, B, C, and D of a specific rectangle in a plan view, respectively, and acoustic signals detected by the four acoustic sensors are referred to as A(s), B(s), C(s), and D(s), respectively;
- a sound arrival time measurement unit configured to calculate sound arrival times from the respective acoustic signals A(s), B(s), C(s), and D(s);
- an ITD generation unit configured to generate six interaural time differences (ITDs) based on a difference in sound arrival time between the acoustic sensor at vertex A and the acoustic sensor at vertex B, between the acoustic sensor at vertex B and the acoustic sensor at vertex C, between the acoustic sensor at vertex C and the acoustic sensor at vertex D, between the acoustic sensor at vertex D and the acoustic sensor at vertex A, between the acoustic sensor at vertex A and the acoustic sensor at vertex C, and between the acoustic sensor at vertex B and the acoustic sensor at vertex D;
- and
- a sound source location estimation unit configured to estimate a location of a sound source based on at least two of the six ITDs,
- wherein estimating the location of the sound source comprises:
- calculating an azimuth angle θ1 formed by a line connecting a first pair of acoustic sensors at the vertices A and D of the four acoustic sensors and a line connecting the sound source and the acoustic sensor at the vertex D based on an ITD between the first pair of acoustic sensors at the vertices A and D;
- calculating an azimuth angle θ2 formed by a line connecting a second pair of acoustic sensors at the vertices B and A of the four acoustic sensors and a line connecting the sound source and the acoustic sensor at the vertex A based on an ITD between the second pair of acoustic sensors at the vertices B and A, wherein the first pair of acoustic sensors at the vertices A and D and the second pair of acoustic sensors at the vertices B and A share the acoustic sensor at the vertex A;
- and
- calculating a distance to the sound source using the calculated azimuth angles θ1 and θ2, a distance VL between the first pair of acoustic sensors at the vertices A and D, and a distance VW between the second pair of acoustic sensors at the vertices B and A.