Robust digit recognition using phase-dependent time-frequency masking

A technique using the time-frequency phase information of two microphones is proposed to estimate an ideal time-frequency mask using time-delay-of-arrival (TDOA) of the signal of interest. At a signal-to-noise ratio (SNR) of 0dB, the proposed technique using two microphones achieves a digit recognition rate (average over 5 speakers, each speaking 20-30 digits) of 71%. In contrast, delay-and-sum beamforming only achieves a 40% recognition rate with two microphones and 60% with four microphones. Superdirective beamforming achieves a 44% recognition rate with two microphones and 65% with four microphones.