Co-channel speaker separation

Abstract

This paper describes a system for the automatic separation of two-talker co-channel speech. This system is based on a frame-by-frame speaker separation algorithm that exploits a pitch estimate of the stronger talker derived from the co-channel signal. The concept underlying this approach is to recover the stronger talker's speech by enhancing harmonic frequencies and formants given a multi-resolution pitch estimate. The weaker talker's speech is obtained from the residual signal created when the harmonics and formants of the stronger talker are suppressed. A maximum likelihood speaker assignment algorithm is used to place the recovered frames from the target and interfering talkers in separate channels. The system has been tested at target-to-interferer ratios (TIRs) from -18 to 18 dB with human listening tests, and with machine-based tests employing a keyword spotting system on the Switchboard Corpus for target talkers at 6, 12, and 18 dB TIR.