Telescopic microphone array using reflector for segregating target source from noises in same direction

A spatial sensitivity control method for segregating the sound sources in the same direction by using an acoustic reflector is proposed. Our goal is to clearly pick up the target source at an arbitrary position using a microphone array. Though many methods have been studied for spatial sensitivity control, it is difficult to robustly suppress the power of noise sources in the same direction of the target source in a room. To overcome this problem, we attach a reflector to a microphone array to capture the reflected sounds whose characteristics vary depending on the distance from the array to the source. Assuming that the acoustical properties of the reflector are known e.g., measuring the transfer functions, those reflected sounds can be used as effective clues for segregating the sound sources in the same direction. With the proposed method, a filter for minimizing the output noise power is derived by taking into consideration of the acoustic properties of the reflector. Experiments were conducted in an actual room by using 96 microphones and a large reflector. We confirmed that the spatial sensitivities for segregating the target source at an arbitrary position from noise sources can be achieved by using the proposed method.