Pilot-assist source separation

Abstract

A challenging problem in current hearing aid technology is source separation of a desired acoustic signal from an unwanted acoustic signal, such as speech, noise, and reverberations. Currently, the approach of blind-source separation, which does not utilize any information about the acoustic path between a speaker and a microphone, runs into difficulty when separating out the desired acoustic signal from the audio mixture when the room is reverberant. To circumvent this issue, the approach that we use is to aid the microphone array system in beamforming through the use of a pilot signal or so-called ‘beacon.’ The beacon is an audible-range or ultrasonic-range acoustic pilot signal that would be placed near the desired acoustic source. It would provide the needed acoustic path information - in the form of an acoustic impulse response - which would help a beamformer, along with the second-order statistics of the interference signals, to separate out the desired acoustic signal and increase its signal-to-noise ratio. Multiple lengths and frequency ranges of pilot signals are tested to determine the most useful pilot signal in a human environment.U of I Onlyundergraduate senior thesis not recommended for open acces