Patent ID: 7451082

Claim:
A method of detecting speech in an incoming signal comprising the steps of: receiving said incoming signal, extracting an estimate of the noise background of the incoming signal and suppressing the noise background of the incoming signal to provide a noise suppressed signal in which the estimated background noise has been removed, filtering the noise suppressed signal in which the background noise has been removed with a spectral inverse filter, said spectral inverse filter is determined by spectrum maxima and the inverse filtering operation comprising the steps of: in the logarithmic (dB) domain, removing the mean spectral magnitude from the original speech spectrum, in the mean removed short term frequency spectrum S(i), (i=l . . .128), determining all the frequency position (Pj), whose magnitudes are maxima over a window centered around Pj and stretching N positions to the left and right of Pj, in the list of peaks, adding the first (i=1) and last (i=128) frequency positions, their associated magnitudes set equal to the mean of the first and last M×N magnitudes, respectively, wherein said M and N are preset constants, removing the mean of the peak magnitudes from each peak magnitude, if the largest resulting peak magnitude exceeds a predetermined maximum peak value MAX_dB_DN, normalizing all peaks so that the largest peaks magnitude becomes MAX_dB_DN, and the resulting inverse filtering H(i) (i=l . . . 128) is defined as the maximum of the normalized peaks and 0 dB, and removing the inverse filter from the original spectrum in the logarithmic domain U(i)=S(i)−H(i) and measuring the periodicity of the signal from the inverse filter using an autocorrelation function to determine whether a signal frame corresponds to a speech frame or not.