JP4804014B2 - Audio conferencing equipment - Google Patents

Description

  The present invention relates to an audio conference apparatus, and can be applied to, for example, an audio conference apparatus and system using a stereo audio signal between two points of a large number of people.

With the widespread use of broadband broadband IP lines such as corporate LAN and ADSL, video conferencing systems between two points (two groups are in different locations) have become widespread. As an audio conference system applied to such a video conference system, a system compatible with VoIP as described in Non-Patent Document 1 has been proposed. This audio conference system uses a terminal having a speaker and a microphone.
NEC Technical Report vol. 56 No12 / 2003

  However, the audio conference system of Non-Patent Document 1 described above has a problem that it is difficult to identify a speaker (who is speaking).

  In order to solve such inconvenience, it is conceivable to install a pair of speakers and microphones so as to be stereo-compatible. However, in the case of an audio conference system, since the volume of the speaker is increased so that a large number of people can listen, even if one speaker and one microphone are provided, the problem of echo is large, and the speaker and microphone are compatible with stereo. In this case, the problem of echo is further increased, and the configuration of the echo canceller becomes complicated and expensive.

  Therefore, an audio conference apparatus that can solve both the speaker identification problem and the echo problem is desired.

The first aspect of the present invention is an audio conference apparatus provided at each of two locations related to a conference that can accommodate up to N participants (N is 3 or more). (1) In the vicinity of each participant's mouth (1) stereo sound composed of an R channel audio signal and an L channel audio signal to which a direction determined by the monaural / stereo conversion means is added to a monaural audio signal from the corresponding monaural microphone; Monaural / stereo conversion means for converting into signals , and (3) combining the R channel audio signals from each of the monaural / stereo conversion means to obtain a synthesized R channel audio signal, and Synthesize the channel audio signal to obtain the synthesized L channel audio signal, Stereo audio transmission means for transmitting an L channel audio signal to the opposing audio conference device, (4) an R channel speaker and an L channel speaker, and (5) a synthesized R channel audio signal from the opposing audio conference device And receiving and distributing means for supplying the L channel speaker with a synthesized L channel audio signal from the opposite audio conference apparatus.

  According to the audio conferencing apparatus of the present invention, when transmitting and receiving a stereo audio signal, a speaker can be selected by using headphones for each participant or using a directional monaural microphone for each participant. This makes it possible to identify and suppress the occurrence of echoes.

(A) 1st Embodiment Hereinafter, the 1st Embodiment which applied the audio conference apparatus of this invention to the audio conference system between many people two points is described, referring drawings.

  FIG. 1 shows a schematic configuration of the audio conference apparatus according to the first embodiment. The audio conference system according to the first embodiment is configured by providing the audio conference apparatus 10 having such a configuration at two opposing points.

  The audio conference apparatus 10 has a transmission configuration for transmitting a stereo audio signal from its own location and a configuration for receiving a stereo audio signal captured at another location.

  The transmission configuration of the audio conference apparatus 10 includes a pair of microphones 21R and 21L and an audio multiplex transmission unit 22.

  Even if the maximum allowable number (N) of conference participants 1-1 to 1-N (N in the example of FIG. 1 is 4) is located on a predetermined straight line or curve (for example, arc), any participant A pair of microphones 21R and 21L is installed so that the position of the sound is sufficiently different and the stereo sound is opposed to each other. Installation is not limited to fixed installation, but the distance between the pair of microphones 21R and 21L is preferably about an average distance between the left and right ears.

  The audio multiplex transmission unit 22 transmits a stereo audio signal obtained by multiplexing the R channel audio signal from the microphone 21R and the L channel audio signal from the microphone 21L to the opposing audio conference apparatus. Here, any existing method may be applied as the multiplexing and transmission method. For example, the audio multiplex transmission unit 22 may convert the R channel audio signal and the L channel audio signal into digital signals, encode them, and multiplex them thereafter, and further multiplex them according to the network to be used. Alternatively, channel modulation or the like may be performed or packetized.

  The reception configuration of the audio conference apparatus 10 includes a reception distribution unit 31 and headphones 32-1 to 32 -N for each participant.

  The receiving / distributing unit 31 separates the stereo audio signal transmitted by the opposing audio conferencing apparatus into the R channel audio signal and the L channel audio signal, and the pair of R channel audio signal and L channel audio signal obtained by the separation. , And the headphones 32-1, ..., 32-N for each participant. Except for the distribution function to the headphones 32-1,..., 32-N for each participant, the reception distribution unit 31 performs the reverse process of the voice multiplex transmission unit 22 described above. For example, if the voice multiplex transmission unit 22 performs channel modulation, the reception distribution unit 31 performs channel demodulation, and if the voice multiplex transmission unit 22 assembles packets, the reception distribution unit 31 receives a received packet. If the audio multiplex transmission unit 22 encodes the audio signal, the reception distribution unit 31 performs decoding.

  The reception distributor 31 may have a headphone jack, and may not distribute a pair of R channel audio signals and L channel audio signals to a jack in which a headphone plug is not inserted.

  Further, some of the functions described above may be assigned to the headphones 32-1,..., 32-N instead of the reception distributor 31.

  Each of the headphones 32-1,..., 32 -N is for outputting the sound related to the R channel audio signal and the L channel audio signal given from the reception distribution unit 31 from the corresponding ear side listening unit. .

  Here, it is preferable that each of the headphones 32-1,..., 32-N has a structure that allows ambient sounds to pass therethrough so that the voices of other participants at the same point can be heard.

  Hereinafter, an operation when the participant at the other point B listens to the pronunciation of the participant at one point A provided for the audio conference will be described. In the following description, “A” is added to the end of the component of the point A, and “B” is added to the end of the reference of the component of the point B.

  When the participant 1-nA at one point A speaks, the pronunciation sound is captured by the pair of microphones 21RA and 21LA of the audio conference apparatus 10A, converted into an R channel audio signal and an L channel audio signal, and audio multiplexed transmission. Is given to the part 22A. In the audio multiplex transmission unit 22A, the R channel audio signal and the L channel audio signal are multiplexed, and the obtained stereo audio signal is transmitted to the opposite audio conference apparatus 10B.

  Such a transmission signal is received by the reception distributing unit 31B of the audio conference apparatus 10B. The reception distributor 31B separates the stereo audio signal transmitted by the opposing audio conference device 10A into an R channel audio signal and an L channel audio signal, and a pair of R channel audio signal and L channel audio signal obtained by the separation. Are distributed to the headphones 32-1B,..., 32-NB of each participant.

  Each of the headphones 32-1B,..., 32-NB of each participant generates a sound corresponding to the R channel audio signal and the L channel audio signal given from the reception distribution unit 31B from the corresponding ear listening unit. Let

  Since each of the participants 1-1B to 1-NB wearing the headphones 32-1B,..., 32-NB listens to the sound of the participant 1-nA in stereo, the positions of the participants 1-nA are determined. It can be distinguished from the other participants 1-1A to 1-NA (except 1-nA), and even at the other point, it is possible to listen to the pronunciation sound while feeling a sense of reality.

  According to the first embodiment, even if the stereo sound signal captured by the pair of microphones is transmitted to the other point, the sound signal is generated by the headphones, so that the echo does not become a problem. Since the listening is performed by stereo, the listener and the position of the speaker are easily recognized by the listener. The configuration for producing such an effect can be simplified and inexpensive.

(B) Second Embodiment Next, a voice conference apparatus of the present invention, the second embodiment applied to a voice conference system between multiplayer point-to-point, will be described with reference to the drawings.

  FIG. 2 shows a schematic configuration of the audio conference apparatus according to the second embodiment. The audio conference system 11 according to the second embodiment is configured by providing the audio conference apparatus 11 having such a configuration at two points facing each other.

  The audio conference apparatus 11 of the second embodiment also has a transmission configuration for transmitting a stereo audio signal from its own location and a configuration for receiving a stereo audio signal captured at another location.

  The transmission configuration of the audio conference apparatus 11 according to the second embodiment includes microphones 21-1 to 21 -N for each participant, localization processing units 41-1 to 41-N for each participant, and an audio multiplexing transmission unit 22. And have.

  Each microphone 21-1 to 21-N for each participant is a monaural output type microphone and has high directivity provided in the vicinity of the corresponding participant's mouth. The microphones 21-1 to 21-N may be provided in the vicinity of the participant's mouth, for example, via an attachment such as a headset. For example, a pin microphone may be applied to the participant's clothes. It may be attached by a pin and provided near the participant's mouth, or may be provided near the participant's mouth using an attachment stand placed on a table or the like. The monaural audio signals from the microphones 21-1 to 21-N are given to the localization processing units 41-1 to 41-N corresponding to the microphones 21-1 to 21-N.

  Each of the localization processing units 41-1 to 41-N performs stereo processing using HRTFs on the monaural audio signals from the corresponding microphones 21-1 to 21-N to add directionality. An audio signal (R channel audio signal and L channel audio signal) is formed. Here, the directionality is fixedly set in advance for each participant. As for the existing localization processing, for example, those described in JP-A-2002-209300 and JP-A-2003-102099 can be applied. Each of the localization processing units 41-1 to 41-N supplies the formed stereo audio signal to the audio multiplex transmission unit 22.

  The audio multiplex transmission unit 22 according to the second embodiment synthesizes the stereo audio signals from the localization processing units 41-1 to 41-N for each of the R channel and the L channel, and then combines the synthesized R channel audio signal and the synthesis. The L-channel audio signal is multiplexed and the resultant synthesized stereo audio signal is transmitted to the opposing audio conference apparatus.

  The reception configuration of the audio conference apparatus 11 according to the second embodiment includes a reception distribution unit 31 and speakers 32R and 32L for the R channel and the L channel.

  The receiving / distributing unit 31 separates the synthesized stereo audio signal transmitted by the opposing audio conference device into a synthesized R channel audio signal and a synthesized L channel audio signal, and a pair of synthesized R channel audio signals and synthesized signals obtained by the separation. The L channel audio signal is given to the speakers 32R and 32L for the R channel and the L channel, respectively.

  The R-channel and L-channel speakers 32R and 32L are for outputting the synthesized R-channel audio signal and the synthesized L-channel audio signal supplied from the reception distribution unit 31, respectively.

  Hereinafter, an operation when the participant at the other point B listens to the pronunciation of the participant at one point A provided for the audio conference will be described. In the following description, “A” is added to the end of the component of the point A, and “B” is added to the end of the reference of the component of the point B.

  When the participant 1-nA at one point A speaks, the pronunciation sound is captured by the monaural microphone 21-nA for the participant 1-nA of the audio conference apparatus 11A, and the monaural audio signal is localized processing unit 41- given to nA. By this localization processing unit 41-nA, the monaural audio signal is converted into a stereo audio signal (R channel audio signal and L channel audio signal) to which directionality is added. The stereo audio signal (R channel audio signal and L channel audio signal) to which such directionality is added is transmitted to the other localization processing units 41-1A to 41-NA (41-nA by the audio multiplex transmission unit 22). Are combined with the stereo audio signal from each other, and then channel-multiplexed and transmitted to the opposite audio conference apparatus 11B.

  Such a transmission signal is received by the reception distribution unit 31B of the audio conference apparatus 11B. The reception distributor 31B separates the synthesized stereo audio signal transmitted by the opposing audio conference device 11A into a synthesized R channel audio signal and a synthesized L channel audio signal, and a pair of synthesized R channel audio signals obtained by the separation and The synthesized L-channel audio signal is applied to the R-channel and L-channel speakers 32R and 32L to generate sound. As a result, each of the participants 1-1B to 1-NB on the receiving side listens to the synthesized R channel sound and synthesized L channel sound that have been subjected to localization processing.

  When the participant other than the participant 1-nA does not sound at the point A, the synthesized R channel sound and the synthesized L channel sound that are received by the respective participants 1-1B to 1-NB on the receiving side are: Only the monaural sound related to the participant 1-nA is localized, and each participant 1-1B to 1-NB recognizes who the pronunciation participant 1-nA is, the position, and the like.

  According to the second embodiment, the monaural sound signal captured by the monaural microphone near the mouth of the speaker is localized and converted into a stereo sound signal with directionality and transmitted to the other point. Therefore, even if the sound signal is generated by a stereo speaker, the echo does not become a problem, and since the listening is performed by stereo, the listener and the position of the speaker can be easily recognized by the listener. It has become.

  Here, since the localization process is used, depending on the setting of directionality, it becomes possible to make the opposing group recognize the virtual seating order different from the actual seating order, and it is more versatile than the first embodiment. It is possible to realize a voice conference.

  As a modified embodiment of the second embodiment, the directionality provided by each localization processing unit 41-1 to 41-N is not fixed but can be variably set. That is, although illustration is omitted, angle information D1 to DN can be input from the outside to each of the localization processing units 41-1 to 41-N, and each of the localization processing units 41-1 to 41-N has its angle information. The directionality defined by D1 to DN is given.

  According to such a modified embodiment, the degree of freedom is increased in the directional operation of the speaker, and a more realistic voice conference can be realized.

(C) Third Embodiment Next, a third embodiment in which the audio conference apparatus of the present invention is applied to an audio conference system between two points of a large number of people will be described with reference to the drawings.

  FIG. 3 shows a schematic configuration of the audio conference apparatus according to the third embodiment, and the same reference numerals are given to the same and corresponding parts as in FIG. 2 according to the second embodiment. The audio conference system 12 according to the third embodiment is configured by providing the audio conference apparatus 12 having such a configuration at two points facing each other.

  Compared to the second embodiment, the audio conference device 12 according to the third embodiment includes localization processing units 41-1 to 41-N that generate stereo audio signals from monaural audio signals. (Balance processing unit) 51-1 to 51-N are different, and the other points are the same as in the second embodiment.

  The n (n is 1 to N) -th balance processing unit 51-n generates an L channel audio signal STn (L) and an R channel audio signal STn (R) from the input monaural audio signal Sn according to the following formula. To do.

STn (L) = Sn * (1-An) STn (R) = Sn * An
However, An = (n-1) / (N-1)
According to the third embodiment, the same effects as those of the second embodiment can be obtained. Furthermore, directionality can be imparted by a simpler process than in the second embodiment.

  As a modified embodiment of the third embodiment, the directionality provided by each balance processing unit 51-1 to 51-N is not fixed but can be variably set. That is, although illustration is omitted, directionality information A1 to AN can be input from the outside to each balance processing unit 51-1 to 51-N, and each balance processing unit 51-1 to 51-N has its direction. The directionality defined by the sex information A1 to AN is given.

  According to such a modified embodiment, the degree of freedom is increased in the directional operation of the speaker, and a more realistic voice conference can be realized.

(D) Fourth Embodiment Next, a fourth embodiment in which the audio conference apparatus according to the present invention is applied to an audio conference system between two points of a large number of people will be described with reference to the drawings.

  FIG. 4 shows a schematic configuration of the audio conference apparatus according to the fourth embodiment, and the same or corresponding parts as those in FIG. 1 according to the first embodiment are denoted by the same reference numerals. The audio conference system 13 according to the fourth embodiment is configured by providing the audio conference apparatus 13 having such a configuration at two points facing each other.

  Compared to the first embodiment, the audio conference apparatus 13 according to the fourth embodiment has a balance processing unit (a receiving side balance processing unit) between the reception distribution unit 31 and the headphones 32-1 to 32-N. The point 61-1 to 61-N is provided, and the distance measurement signals (wireless, infrared, etc.) are transmitted to the balance processing units 61-1 to 61-N corresponding to the headphones 32-1 to 32-N. It is different in that it has a function.

  Each of the headphones 32-1 to 32-N transmits a distance measurement signal from the left ear listening unit and transmits a distance measurement signal from the right ear listening unit.

  Each balance processing unit 61-1 to 61-N receives the distance measurement signal transmitted from the left ear listening unit and the right ear listening unit of the corresponding headphones 32-1 to 32-N, and the left ear listening unit. And the distances r1 and r2 to the right ear listening unit, and the stereo audio signals (R channel audio signal R and L channel audio signal L) from the reception distribution unit 31 are corrected as follows, and the corrected stereo audio is corrected. Signals (R channel audio signal RM, L channel audio signal LM) are applied to the corresponding headphones 32-1 to 32-N.

LM = L * r2 / (r1 + r2)
RM = R * r1 / (r1 + r2)
According to the fourth embodiment, the same effect as that of the first embodiment can be obtained. Furthermore, it is possible to feel that the speaker is in the same position regardless of the orientation of the listener, and a voice conference with a sense of reality is possible from the first embodiment.

  For example, even if the listener 1-n is facing the balance processing unit 61-n as shown in FIG. 5A, the listener 1-n is placed on the left side of the balance processing unit 61-n as shown in FIG. Even if it is facing, it can be felt that the speaker is at the same position by the correction processing of the balance processing unit 61-n. Incidentally, in the case of the first embodiment, the position at which the speaker feels changes depending on the direction of the listener 1-n.

  In the fourth embodiment, it has been shown that the head direction of the listener is obtained by communication between the headphones and the balance processing unit. However, the head direction detection method is not limited to this. is there. Also, the correction method according to the head direction of the stereo audio signal is not limited to the correction method based on the above-described formula, and may be appropriately selected according to the head direction detection method.

(E) Other Embodiments The transmission configuration of the i-th embodiment (including the modified embodiment) and the receiving configuration of the j-th (j is different from i) embodiment (including the modified embodiment). If possible, a voice conference device may be realized by combining. For example, an audio conference device having the transmission configuration of the third embodiment and the reception configuration of the fourth embodiment may be used.

  The audio conference apparatus and audio conference system of the present invention may be realized as an audio processing unit such as a video conference, or may be realized as a single audio conference apparatus.

It is a block diagram which shows schematic structure of the audio conference apparatus of 1st Embodiment. It is a block diagram which shows schematic structure of the audio conference apparatus of 2nd Embodiment. It is a block diagram which shows schematic structure of the audio conference apparatus of 3rd Embodiment. It is a block diagram which shows schematic structure of the audio conference apparatus of 4th Embodiment. It is explanatory drawing of the effect of the audio conference apparatus of 4th Embodiment.

Explanation of symbols

10 to 13: Audio conferencing apparatus, 21R, 21L, 211-1 to 21-N: Microphone, 22: Audio multiplexing transmission unit, 31: Reception distribution unit, 32-1 to 32-N: Headphone, 32R, 32L ... Speaker , 41-1 to 41-N: localization processing unit, 51-1 to 51-N ... balance processing unit on transmission side, 61-1 to 61-N ... balance processing unit on reception side.

Claims (4)

In the audio conference apparatus provided at each of the two locations related to the conference, which can accommodate up to N participants (N is 3 or more),
A directional monaural microphone provided near the mouth of each participant;
Monaural / stereo conversion means for converting a monaural audio signal from a corresponding monaural microphone into a stereo audio signal composed of an R channel audio signal and an L channel audio signal to which a direction determined by the monaural / stereo conversion means is added ;
The R channel audio signal from each of the monaural / stereo conversion means is synthesized to obtain a synthesized R channel audio signal, and the L channel audio signal from each of the monaural / stereo conversion means is synthesized to obtain a synthesized L channel audio signal. Stereo audio transmission means for transmitting the synthesized R channel audio signal and the synthesized L channel audio signal to the opposing audio conference device;
An R channel speaker and an L channel speaker;
Receiving and distributing means for providing a synthesized R channel audio signal from the opposite audio conference device to the R channel speaker and providing a synthesized L channel audio signal from the opposite audio conference device to the L channel speaker. An audio conference apparatus. Each mono / stereo conversion means, depending on the parameters defining the direction designated from the outside, according to claim 1, characterized in that the monaural audio signal is of variable configuration for converting to the stereo audio signal The audio conference device according to 1. Each mono / stereo conversion means, based on the localization data, by localization processing using the HRTF, wherein said monaural audio signals to claim 1 or 2, characterized in that to convert to the stereo audio signal Audio conferencing equipment. 3. The audio conference according to claim 1, wherein each of the monaural / stereo conversion means converts the monaural audio signal into the stereo audio signal by weighting processing based on weighting information. apparatus.

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