Patent ID: 7359856

Claim:
A method of detecting speech in an audio signal, the method comprising a step of obtaining information on the energy of the audio signal and a step of obtaining information on the voicing of the audio signal from fundamental frequency values calculated periodically over the whole of the audio signal, said voicing information then being used in conjunction with the energy information to detect speech in the audio signal, wherein the audio signal is made up of successive frames n each sub-divided into P sub-frames m , where m=P·n+i with i varying from 0 to P−1, and the step of obtaining said voicing information comprises the following sub-steps: calculating for each sub-frame m the median value med(m) of a predetermined number of fundamental frequency values of the audio signal, calculating for each sub-frame m the arithmetic mean δmed (m) of the absolute values of the differences between a current median value and the preceding median value, said differences being calculated for the N sub-frames preceding the current sub-frame m , and said arithmetic mean being obtained from the following equation: δ ⁢ ⁢ med _ ⁢ ( m ) = 1 N ⁢ ∑ k = 0 N - 1 ⁢  med ⁡ ( m - k ) - med ⁡ ( m - k - 1 )  in which N is the size of the arithmetic window, med(m) is the median value calculated for the sub-frame m, m−d (where d is natural integer) designates the d th sub-frame preceding the current sub-frame m , and m=P·n+i with i=0, 1, 2, . . . , P−1, said voicing information calculated over the whole of the audio signal consisting of said arithmetic means δmed (m), each of which constitutes a voicing parameter indicative of the degree of voicing of the audio signal for the sub-frame m concerned.