Method and device for comparing signals to control transducers and transducer control system

Abstract

A method of comparison between pieces of information characterizing reference values and pieces of information characterizing current values of sound-reproducing systems of a system of (n) microphones m i and (p) speakers hp j for the control of said sound-reproducing systems characterized in that: A: for each speaker hp j , at least one sound signal S is sent on the speaker hp j , for each microphone m i , a piece of information hp j m i is retrieved, this piece of information characterizing the sound-reproducing system comprising the speaker hp j and the microphone m i , B: a reference matrix Q r is saved, this reference matrix being constituted by all the pieces of reference information hp j m i obtained following the sending of the sound signal S, C: as soon as a comparison is to be made, the step A is run with a sound signal S′ to obtain current information on a matrix Q, D: the matrices Q and Q r are compared.

1 . Method of comparison between pieces of information characterizing reference values and pieces of information characterizing current values of sound-reproducing systems of a system of (n) microphones m i  and (p) speakers hp j  for the control of said sound-reproducing systems characterized in that: 
 A: for each speaker hp j , 
 at least one sound signal S is sent on the speaker hp j ,  
 for each microphone m i , a piece of information hp j m i  is retrieved, this piece of information characterizing the sound-reproducing system comprising the speaker hp j  and the microphone m i ,  
   B: a reference matrix Q r  is saved, this reference matrix being constituted by all the pieces of reference information hp j m i  obtained following the sending of the sound signal S,    C: as soon as a comparison is to be made, the step A is run with a sound signal S′ to obtain current information on a matrix Q,    D: the matrices Q and Q r  are compared.    
     
     
         2 . Method according to  claim 1  characterized in that, when the pieces of information hp j m i  of Q are not directly comparable with the pieces of information of Q r , a processing operation, capable of converting them into information directly comparable with the information of the other matrix, is applied to the elements hp j m i  from a Q or Q r  by choice, before the step D.  
     
     
         3 . Method according to one of the claims  1  or  2  characterized in that the pieces of information hp j m i  of Q r  and/or of Q are the spectral responses of each sub-system including a speaker hp j  and a microphone m i .  
     
     
         4 . Method according to  claim 3 , characterized in that the signals sent by the speakers hp j  are transmitted in a frequency band with a determined width, and in that said frequency band is made to slide in order to sweep through the desired spectrum of frequencies.  
     
     
         5 . Method according to one of the claims  1  or  2 , characterized in that the pieces of information hp j m i  of Q r  and/or of Q are the impulse responses of each sub-system including a speaker hp j  and a microphone m i .  
     
     
         6 . Method according to one of the claims  1  or  2 , characterized in that the pieces of information hp j m i  of Q r  and/or of Q are the transfer functions of each sub-system including a speaker hp j  and a microphone m i .  
     
     
         7 . Method according to one of the claims  1  or  2 , characterized in that the pieces of information hp j m i  of Q r  and/or of Q are the gains between the microphones m i  and the speakers hp j  following the signals sent by the speakers hp j .  
     
     
         8 . Method according to one of the  claims 1  to  7  characterized in that, from the matrices Q and Q r , 
 the mean values respectively of the speakers hp j , referenced HP jQ  and HP jQr , are computed by computing: 1/p*Σ i  hp j m i ,  
 and when the value HP jQ /HP jQr  is outside a predetermined speaker range FHP, the sound-reproducing system comprising the speaker hp j  is corrected by a divergence corresponding to HP jQr /HP jQ .  
 
     
     
         9 . Method according to  claim 8 , characterized in that, in the sound-reproducing system comprising the speaker hp j , the gain of speaker hp j  is corrected.  
     
     
         10 . Method according to one of the  claims 1  to  7 , characterized in that, from the matrices Q and Q r , 
 the mean values respectively of the microphones m i , referenced M iQ  and M iQr , are computed by computing: 1/n*Σ i  hp j m i ,  
 and when the value M jQ /M jQr  is outside a predetermined microphone range FM, the sound-reproducing system comprising the microphone m i  is corrected by a divergence corresponding to M iQr /M iQ .  
 
     
     
         11 . Method according to  claim 10 , characterized in that, in the sound-reproducing system comprising the microphone m i , the gain of the microphone m i  is corrected.  
     
     
         12 . Method according to one of the  claims 1  to  11 , characterized in that the pieces of information hp j m i  of the matrices Q and Q r  to be compared represent delays between the sending of the sound signal by each speaker hp j  and the reception of said sound signal by the microphones m i .  
     
     
         13 . Method according to one of the  claims 8  to  11 , the pieces of information hp j m i  of Qr and of Q being the impulse responses of each sub-system including a speaker hp j  and a microphone m i , characterized in that the pieces of information hp j m i  represent the signals that were received by the microphone m i  and have traveled the direct path between the speaker hp j  and the microphone m i .  
     
     
         14 . Method according to one of the  claims 8  to  11 , the pieces of information hp j m i  of Qr and of Q being the impulse responses of each sub-system including a speaker hp j  and a microphone m i , characterized in that the pieces of information hp j m i  represent the signals that were received by the microphone m i  and have traveled the paths with one or more reflections between the speaker hp j  and the microphone m i .  
     
     
         15 . Method according to one of the  claims 1  to  14 , characterized in that the signal S′ is a silence signal and in that, from the matrices Q and Q r , the mean values of the microphones m i , referenced M iQ  and M iQr , are computed respectively in computing: 1/n*Σ j  hp j m i , to thus obtain the signal-to-noise ratio M iQr /M iQ  of the microphones m i .  
     
     
         16 . Method according to one of the above claims, characterized in that the pieces of information hp j m i  are processed remotely through a telecommunications or computer network.  
     
     
         17 . Method according to one of the  claims 1  to  15  characterized in that the signals S and S′ come from a remote room connected to a local room through a telecommunications network and wherein the pieces of information hp j m i  are processed in the local room.  
     
     
         18 . Method according to one of the  claims 1  to  11 , characterized in that the pieces of information hp j m i  of Q r  and Q to be compared represent the echo and in that the signals S and S′ come from a remote room connected to a local room through a telecommunications network.  
     
     
         19 . Method for the comparison of information characterizing sound-reproducing systems, at a point of a telecommunications network connecting remote rooms equipped with a system of n microphones m i  and p speakers hp j , each room being connected to the point of the network by one or more transmission channels k, characterized in that the sound-reproducing systems r k e k′  comprise a transmission channel k and a transmission channel k′ resulting from one or more sound-reproducing systems hp j m i  internal to each room processed according tone of the  claims 1  to  18 , and in that the elements of the matrices Q and Q r  represent pieces of information characterizing the sound-reproducing systems r k e k′ .  
     
     
         20 . Method according to one of the above claims, characterized in that the signals S and/or S′ are constituted by a white noise or a pink noise or an USASI noise or a pseudo-random binary sequence.  
     
     
         21 . Method according to one of the  claims 1  to  20 , characterized in that it consists in using the same signal S to obtain the matrices Q r  and Q.  
     
     
         22 . Device for comparing pieces of information characterizing reference values and pieces of information characterizing current values of sound-reproducing systems of a system of n microphones m i  and p speakers hp j  for the control of the sound-reproducing system, characterized in that the control system comprises means for the measurement of the pieces of information hp j m i  characterizing the sound-reproducing systems comprising a microphone m i  and a speaker hp j , digital processing means to compare said pieces of information hp j m i  and, connected to these digital processing means, means for saving the matrix Q r  constituted by all the pieces of information hp j m i .  
     
     
         23 . Device according to  claim 22 , characterized in that the digital processing means comprise means for the comparison of the matrix Q r  and a matrix Q constituted by pieces of information hp j m i  characterizing the current values.  
     
     
         24 . Device according to  claim 22  or  23 , characterized in that the digital processing means comprise means to generate sound signals (S) on the speakers hp j .  
     
     
         25 . Device according to  claim 24 , characterized in that the sound signals (S) may be a white noise or a pink noise or an USASI noise or a pseudo-random binary sequence.  
     
     
         26 . Device according to one of the  claims 22  to  25 , characterized in that the processing means comprise means to correct the sound-reproducing system comprising a speaker hp j  and a microphone m i .  
     
     
         27 . Device according to  claim 26 , characterized in that, in the sound-reproducing system comprising the speaker hp j , the gain of the speaker hp j  is corrected.  
     
     
         28 . Device according to  claim 26 , characterized in that, in the sound-reproducing system comprising the microphone m i , the gain of the microphone m i  is corrected.  
     
     
         29 . System for the control of sound-reproducing systems comprising several devices according to one of the  claims 22  to  28 , characterized in that the devices are distributed among several rooms and in that the control system comprises a high bit-rate telecommunications network connecting said rooms and means to centralize the management of the devices.  
     
     
         30 . System according to  claim 29 , characterized in that the means to centralize the management of the devices are located at a point of the telecommunications network connecting the remote rooms, each room being connected to the point of the network by one or more transmission channels k, in that the sound-reproducing systems r k e k′  comprising a transmission channel k and a transmission channel k′ result from one or more sound-reproducing systems hp j m i  internal to each room and in that it comprises means to correct the sound-reproducing systems r k e k′ .