Patent ID: 7039200

Claim:
A computer-implemented process for estimating the time delay of arrival (TDOA) between a pair of audio sensors of a microphone array, comprising using a computer to perform the following process actions: inputting signals generated by the audio sensors; and estimating the TDOA using a generalized cross-correlation (GCC) technigue which, employs a provision for reducing the influence from correlated ambient noise by applying Wiener filtering to the audio sensor signals, said Wiener filtering comprising multiplying the Fourier transform of the cross correlation of the sensor signals by a factor representing the percentage of the non-noise portion of the overall signal from the first sensor and a factor representing the percentage of the non-noise portion of the overall signal from the second sensor, wherein, computing the factor representing the percentage of the non-noise portion of the overall signal from the first sensor comprises subtracting the overall noise power spectrum of the signal output by a first of the sensors, as estimated when there is no speech in the sensor signal, from the energy of the sensor signal output by the first sensor, and then dividing the difference by the energy of the sensor signal output by the first sensor, and computing the factor representing the percentage of the non-noise portion of the overall signal from the second sensor comprises subtracting said overall noise power spectrum of the signal output by a second of the sensors from the energy of the sensor signal output by the second sensor, and then dividing the difference by the energy of the sensor signal output by the second; and employs a weighting factor for reducing the influence from reverberation noise.