Patent ID: 7068798

Claim:
Method for canceling echoes and noises in environments with variable acoustic conditions and high feedback inside a vehicle for the purpose of permitting the establishment of a clear audible communication between the occupants of the different areas of said vehicle, the method comprising: receiving an existing original speech signal ( 5 ) in at least a first microphone ( 1 ) located in a first site; generating an electric signal from said original speech signal using an assembly comprising several A/D-D/A converters, amplifiers and filters; receiving said electric signal in at least one speaker ( 3 ) to transform said electric signal ( 13 ) into an acoustic signal ( 7 ) susceptible to being received by said first microphone ( 1 ) together with a new original speech signal ( 5 ) and noise ( 9 ), said new original speech signal and noise existing near said first site; removing feedback by applying an operative acoustic echo canceller system ( 15 ) using said electric signal ( 13 ) which will be reproduced, and an electric signal ( 10 ) supplied by the microphone and A/D converter means, the signal ( 10 ) comprising the feedback of said reproduced acoustic signal ( 7 ), a new existing, original speech signal ( 5 ) and a noise ( 9 ) seized by the microphone; and carrying out additional filtering of an electric output signal ( 11 ) of said acoustic echo canceller system ( 15 ), resulting from the treatment of said signal ( 10 ) sent by the microphone ( 1 ), the additional filtering comprising a two-stage Wiener filter ( 16 ), coupled in cascade, a first of them ( 22 ) applied to the elimination of a possible residual echo not suppressed by the echo canceller system ( 15 ) and a second stage ( 23 ) intended to suppress the noise components ( 9 ) of the interior present in said signal ( 11 ), the calculation of the frequency response of both stages ( 22 , 23 ) being carried out by a spectral power density estimate of said residual echo and by a spectral power density estimate of said noise present in said signal ( 11 ).