Abstract: A sound capture device is disclosed, including plural microphone capsules, distributed over portion P of sphere S circumscribed between two or three planes perpendicular to each other, the three planes intersecting at a point corresponding to the center of the sphere S, and the two planes intersecting at a straight line passing through the center of the sphere S, and the sphere portion P being such that P=n S/8, with n=1,2; and a processing unit connected to the capsules to receive the signals captured by the capsules. The processing unit is arranged to matrix the signals in an ambisonic representation which retains only the ambisonic components associated with spherical harmonics that are symmetrical in relation to at least two of the aforementioned planes, and process a matrix thus obtained to identify a sound source surrounding the sphere portion and interpret a sound signal from the source.

Abstract: A sound capture device is disclosed, including plural microphone capsules, distributed over portion P of sphere S circumscribed between two or three planes perpendicular to each other, the three planes intersecting at a point corresponding to the center of the sphere S, and the two planes intersecting at a straight line passing through the center of the sphere S, and the sphere portion P being such that P=n S/8, with n=1,2; and a processing unit connected to the capsules to receive the signals captured by the capsules. The processing unit is arranged to matrix the signals in an ambisonic representation which retains only the ambisonic components associated with spherical harmonics that are symmetrical in relation to at least two of the aforementioned planes, and process a matrix thus obtained to identify a sound source surrounding the sphere portion and interpret a sound signal from the source.

Abstract: A method is provided for determining an indicator evaluating the voice quality of a coded speech signal. The method includes the following steps: calculation per signal frame, of a predetermined number of coefficients of a linear prediction filter for the coded speech signal; determination per frame, of a speech signal reconstructed on the basis of the filter coefficients thus calculated; obtaining per sample, of the residual between the coded speech signal and the reconstructed speech signal; calculation of an evaluation indicator on the basis of the mean or the absolute value of the residuals obtained for all the samples. Also provided are a device for determining an indicator implementing the above method, a method of evaluating the quality or of identifying the class of coding of the coded signal using the indicator determined, as well as a measurement terminal implementing these methods.

Abstract: A method is provided for determining an indicator evaluating the voice quality of a coded speech signal. The method includes the following steps: calculation per signal frame, of a predetermined number of coefficients of a linear prediction filter for the coded speech signal; determination per frame, of a speech signal reconstructed on the basis of the filter coefficients thus calculated; obtaining per sample, of the residual between the coded speech signal and the reconstructed speech signal; calculation of an evaluation indicator on the basis of the mean or the absolute value of the residuals obtained for all the samples. Also provided are a device for determining an indicator implementing the above method, a method of evaluating the quality or of identifying the class of coding of the coded signal using the indicator determined, as well as a measurement terminal implementing these methods.

Abstract: The invention relates to a method of processing a noisy sound signal and to a device for implementing said method. The inventive method includes the following steps which are performed for each frame of a noisy sound signal, consisting in: applying a frequency-domain transform; estimating a power spectral density (PSD) of the noise for the frame; calculating a first noise reduction filter from the estimated PSD of the noise and from an estimation of the PSD of a wanted signal corresponding to the frame; filtering the frame with the aid of the calculated noise reduction filter, in order to obtain a first noise-corrected estimation for the frame; and obtaining a frame of a second signal from the first noise-corrected estimation of the aforementioned frame, comprising harmonics which are essentially at the same positions as the wanted signal corresponding to the frame of the noisy sound signal.

Abstract: The invention relates to a method of processing a noisy sound signal and to a device for implementing said method. The inventive method comprises the following steps which are performed for each frame (x(k,n)) of a noisy sound signal, consisting in: applying a frequency-domain transform; estimating a power spectral density (PSD) of the noise for the frame (?bb(k,f)): calculating a first noise reduction filter (H1(k,f)) from the estimated PSD of the noise and from an estimation of the PSD of a wanted signal corresponding to the frame (?ss (k,f)); filtering the frame (x(k,n); X(k,f)) with the aid of the calculated noise reduction filter, in order to obtain a first noise-corrected estimation for the frame (S1(k,f)); and obtaining a frame of a second signal (Sharmo(k,f)) from the first noise-corrected estimation of the aforementioned frame, comprising harmonics which are essentially at the same positions as the wanted signal corresponding to the frame of the noisy sound signal.