Noise reduction for sound capturing by creating spatial null sensitivity point

We had developed a sound source separation system in which two microphones had been arranged in a line toward sound sources to form null sensitivity points at the source positions by solving the weighting coefficients for microphone outputs. The system achieved the sound source separation by excluding non-target sound sources, instead of extracting target sound sources. In this study, we propose the sound capturing system by which the user can set the null sensitivity point at the arbitrary position. The null sensitivity point is formulated as a function of the weight coefficients. The gain function is also defined as a function of a spatial position. The proposed system uses these functions to capture the target sound while suppressing the non-target sound. A computer simulation showed that, instead of a null sensitivity point, the proposed system generated the circular null sensitivity area whose center was at the microphone position.