3-Dimensional real-time BSS-microphone with spatio-temporal gradient analysis

This paper presents an autonomous directivity microphone system based on the newly proposed spatio-temporal gradient blind source separation. The blind source separation principally uses no a priori knowledge about parameters of convolution, filtering and mixing. In the simplest case of the blind source separation problems, observed mixed signals are linear combinations of unknown mutually statistically independent, zero-mean source signals. The blind signal separation algorithm utilizes the linearity among the four signals: (1) the temporal gradient of sound pressure from each source, (2)x, (3)y, and (4)z-directional gradient of observed sound pressure, all of which are governed by the wave equation and the equation of motion. The proposed method, therefore, has an ability to simplify the convolutive blind source separation problems into the instantaneous blind source separation over the spatio-temporal gradient space. Real-world real-time BSS, with the above result, can be performed with the newly proposed 3-dimensional spatial gradient microphones successfully.