Sextant Avionique

Dominique Pastor

G&eacute;rard Reynaud

Pierre-Albert Breton

The disclosed method uses the Wiener frequency filtering to suppress noise in noisy sound signals (u(t)). This method includes a preliminary step in which the sound signals (u(t)) to be noise-suppressed are digitized by sampling and subdivided into frames. The method then includes a first series of steps including the creation of a noise model on N frames, the estimating of the spectral density of the noise and of the energy of the noise model and the computing of a coefficient that reflects the statistical dispersion of the noise. It also includes a second series of steps including the computation of the spectral density of the signals to be noise-suppressed fore each frame. The coefficients of the Wiener filter are modified for each successively processed frame, by the parameters determined at the end of the two series of steps, so as to introduce an energy compensation and an adaptive overestimation of the noise.

Method of frequency filtering applied to noise suppression in signals implementing a wiener filter

A process for the denoising of audio signals picked up in a noisy environment, for example in the cockpit of an aircraft or of another vehicle, and more precisely to the searching for a noise model in the audio signals. Input signals are digitized, and these signals are processed on the basis of a noise model, in principle with a view to eliminate as far as possible the noise corresponding to the model. The input signals are chopped into successive frames of P samples each, and a repetitive search for a noise model is performed continuously in the input signals themselves, by searching for N successive frames (N lying between a minimum N1 and a maximum N2) having the expected characteristics of a noise, by storing N&times;P corresponding samples so as to construct a noise model useful in the denoising processing of the input signals and by iteratively repeating the search so as to find a new noise model and to store the new noise model as a replacement for the previously stored noise mode or to retain the previously stored noise model according to the respective characteristics of the two models. The model is obtained by finding N frames whose energies are close to one another (ratio of energies lying between two values S and 1/S).

Growing community of inventors

Hengelo, Netherlands

Dominique Pastor