A system for separating sound sources propagated in the same direction

This paper describes a microphone system that separates a target sound from other noise arriving in a single direction when the target cannot, therefore, be separated by directivity control. Microphones are arranged in a line toward the sources to form sensitivity points at certain distances from the system. The points exclude nontargeted sound sources on the basis of weighting coefficients for microphone outputs determined by blind source separation. The separation problem is thereby simplified into the instantaneous separation by adjusting the time-delays for microphone outputs. The system uses a direct (i.e. non-iterative) algorithm for blind separation based on second-order statistics, assuming that all sources are non-stationary signals. Simulations show that the 2-microphone system separates a target sound with separability of more than 40 dB in the 2-source problem, and 25 dB in the 3-source problem.