Abstract: A method of detecting speech in an audio signal comprises a step of obtaining information on the energy of the audio signal, the energy information then being used to detect speech in the audio signal. The method further comprises a step of obtaining information on the voicing of the audio signal, the voicing information then being used in conjunction with the energy information to detect speech in the audio signal.

Abstract: The device calculates a first frequency-dependent useful signal level estimator for the frame. The transfer function of a first noise-reducing filter is determined on the basis of the first useful signal level estimator and of a frequency-dependent noise level estimator. A second frequency-dependent useful signal level estimator for the frame is then calculated by combining the spectrum of the input signal and the transfer function of the first noise-reducing filter. The transfer function of a second noise-reducing filter is determined on the basis of the second useful signal level estimator and of the noise level estimator. The latter transfer function is used in a frame filtering operation to produce a signal with reduced noise.

Abstract: A method of detecting speech in an audio signal comprises a step of obtaining information on the energy of the audio signal, the energy information then being used to detect speech in the audio signal. The method further comprises a step of obtaining information on the voicing of the audio signal, the voicing information then being used in conjunction with the energy information to detect speech in the audio signal.

Abstract: The invention concerns a method which consists, when analysing an input signal in the frequency domain, in determining a noise level estimator and a useful signal level estimator in an input signal frame, thereby enabling to calculate the transfer function of a first noise-reducing filter, carrying out a second pass to fine-tune the useful signal level estimator, by combining the signal spectrum and the first filter transfer function, then to calculate the transfer function of a second noise-reducing filter on the basis of the fine-tuned useful signal level estimator and the noise level estimator. Said second noise-reducing filter is then used to reduce the noise level in the frame.

Abstract: A process and device for blind equalization of the effects of a transmission channel on a speech signal. The speech signal is transformed into cepstral vectors which are representative of the speech signal over a given horizon. A reference cepstrum consisting of a constant cepstrum signal representative of the long-term cepstrum of the speech signal is calculated for each cepstral vector. Each of the cepstral vectors is subjected to adaptive filtering by LMS on the basis of the reference cepstrum so as to generate a set of equalized cepstral vectors on the basis of the calculation of an error signal between the reference cepstrum and equalized cepstral vectors. The error signal is expressed as the difference between the reference cepstrum component of a given rank and the component of the same rank of the equalized cepstral vector.