JPH06284419A - Multi-point video conference system - Google Patents

Abstract

PURPOSE:To prevent a picture from being disappeared even when a terminal equipment having no video picture transmitter is connected to a video conference equipment. CONSTITUTION:A conference processor 15 instructs a picture selection section 12 so that a voice level from each conference terminal is measured and a picture from a conference terminal with a largest level is selected. When a terminal equipment having no video transmission function is selected to be a terminal equipment having a highest voice level, the conference processor 15 sends character information relating to the terminal equipment to a character insertion section 13 and the character information is displayed while being superimposed on a television picture having been displayed so far. Thus, who is a speaker is easily recognized.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a multipoint video conference system,
In particular, a TV conference device connected to a plurality of conference terminals having a TV camera and an image display unit via an exchange transfers the received voice information to each conference terminal and the TV of the conference terminal with the highest sound pressure level of the speaker. The present invention relates to a multipoint video conference system for selecting an image and transmitting it to each conference terminal.

[0002]

2. Description of the Related Art Conventionally, in this type of multipoint video conference system, a conference terminal equipped with a video camera and an image display unit is connected to a single video conference device in advance via a switchboard to obtain the most audio during a conference. The image display unit of each conference terminal displays the image captured by the TV camera of the conference terminal with the speaker having a high pressure level.

This will be described with reference to the block diagram of FIG.

As shown in FIG. 12, a plurality of conference terminals 3
1, 32, and 33 are connected to the exchange bus 81 via the respective interfaces of the line interface unit 82 of the exchange 80, and the exchange bus 81 connects the lines of the number corresponding to the conference participation capacity to the video conference device 90.

In the exchange 80, the exchange processor 83 controls the connection of the exchange bus 81. That is, when the exchange processor 83 receives via the line interface unit 83 a request to participate in one video conference with a predetermined number,
The requested conference terminals are sequentially connected to the lines accommodated in one video conference device 90.

The video conference device 90 has a television image processing unit of the distribution unit 11 and the image selection unit 12, a conference voice processing unit (not shown), and a conference processor 91.

A conference voice processing unit (not shown) mixes the voices received from each conference terminal and outputs the mixed voices again to each conference terminal via a line and measures the sound pressure level of the received voice for each line. , Conference processor 91 as sound pressure information
Output to.

The distribution unit 11 can distribute the television image from each connection line to all of these lines. That is, the television images from all the connection lines are input to the circuit unit 121 for each line in the image selection unit 12, and one of these input images is selected and output.

The conference processor 91 receives the sound pressure information from the above-mentioned conference voice processing unit, selects one of the lines having the highest sound pressure level and instructs the image selection unit 12 to select it as the highest sound pressure level. The lines other than the selected line are switched so that the TV image input from the selected line is selected and output. At this time, on the selected line, the old screen image selected up to that point, in other words, the television image of the old speaker remains as it is.

[0010]

As described above, in the conventional multipoint video conference system, the television image displayed on the image display unit of the conference terminal is switched depending on the voice level of the participants of the video conference. Therefore, when a request to participate in a video conference is received from a telephone terminal that does not have a TV camera and this telephone terminal is connected to the video conference device, when the speech of this telephone terminal is detected as the highest sound pressure level, , There was a problem that there is no TV image to be projected.

An object of the present invention is to display the character information relating to the speaker on the image display unit on the screen when a message from a terminal having no television image transmission function is detected as the highest sound pressure level. An object is to provide a multipoint video conference system that solves the above problems.

[0012]

According to a first basic configuration of a multipoint video conference system according to the present invention, a video conference device connected to a plurality of conference terminals having a video camera and an image display unit via an exchange receives a signal. In the multipoint video conferencing system that transfers the audio information to each conference terminal and selects the television image of the conference terminal with the highest sound pressure level of the speaker and transmits it to each conference terminal, it has a function of transmitting image information. When a video conference participation request is received from a terminal that is not present, the participation request terminal is connected to the video conference device as a conference terminal, and a voice that includes both character information about this conference terminal and connection channel information to the video conference device. The exchange is equipped with an exchange processor for outputting channel information to a video conference device, and an audio channel received from the exchange processor is provided. When one of the connection channels included in the channel information becomes the newly selected channel at the highest sound pressure level, and the image switching condition occurs, the image switching procedure to this newly selected channel is stopped and transmitted to each conference terminal. The video conference device has a video conference device in which the character information of the newly selected channel is formed in a video image and inserted into the image information.

According to a second basic configuration of the present invention, a video conference apparatus connected to a plurality of conference terminals having a television camera and an image display unit via an exchange transfers the received voice information to each conference terminal. In addition, in the multipoint video conference system in which the TV image of the conference terminal with the highest sound pressure level of the speaker is selected and transmitted to each conference terminal, one of the conference terminals receives and displays the television image on the image display unit. While inserting the character information received from the exchange through the predetermined data channel into the information and displaying it on the image display unit, the image information in which the character information is inserted instead of the image of the TV camera of the own terminal is displayed through the selector. When a request for participation in a video conference is received from a terminal that does not have the image information transmission function and becomes a specific conference terminal to be sent to the exchange, this participation request terminal becomes the conference terminal. One audio channel received from the video conferencing device while connected to the video conferencing device and outputting audio channel information including both character information relating to this conference terminal and connection channel information to the video conferencing device to the video conferencing device An exchange processor for transmitting information to the specific conference terminal via the data channel is provided in the exchange, and one of the connection channels included in the voice channel information received from the exchange processor becomes a new selected channel at the highest sound pressure level. When the image switching condition occurs, the image selection to the specific conference terminal is held as it is, and the television image to the conference terminal other than the specific conference terminal is switched to the television image transmitted from the specific conference terminal, A voice channel for the newly selected channel is sent to the exchange processor. And a conference processor for transmitting channel information.

According to a third basic configuration of the present invention, a video conference apparatus connected to a plurality of conference terminals having a television camera and an image display unit via an exchange transfers the received voice information to each conference terminal. In addition, in the multipoint video conference system in which the TV image of the conference terminal with the highest sound pressure level of the speaker is selected and transmitted to each conference terminal, all the conference terminals receive the television and display it on the image display unit. Request to participate in a video conference from a terminal that has a character insertion unit that inserts character information received from the exchange through a predetermined data channel into the image information and outputs it to the image display unit, and that does not have the image information transmission function. When the connection request terminal is received, the participation request terminal is connected to the video conference device as a conference terminal, and the character information about the conference terminal and the connection to the video conference device are connected. While outputting audio channel information including both channel information to the video conference device, one audio channel information received from the video conference device is sent to at least all conference terminals having an image information receiving function via the data channel. An exchange processor for transmitting is provided in the exchange, and when one of the connection channels included in the voice channel information received from the exchange processor becomes a newly selected channel at the highest sound pressure level and an image switching condition occurs, the conference terminal Of the television image is held as it is and the conference processor is provided for transmitting the audio channel information regarding the newly selected channel to the exchange processor.

[0015]

[Operation] First and third of the above-mentioned multipoint video conference system
According to the basic configuration of the above, when a speech from a telephone terminal or a terminal that does not have a function of transmitting image information, such as a camera failure, is superimposed on the TV image being displayed, and the information about the speaker is written in characters. Projected.

Further, in the case of the second basic configuration, with respect to a message from a terminal that does not have a function of transmitting image information, the information about the speaker is superimposed on the television image projected on the specific conference terminal until then. Is printed in letters.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a functional block diagram for explaining the first embodiment of the present invention, FIG. 2 is a flow chart showing an example of the main operation procedure according to FIG. 1, and FIG. 3 is an example of a transmission path of a television image during a conference. It is a connection diagram showing.

The video conference unit 10 shown in FIG. 1 has a distribution unit 11, an image selection unit 12, a character insertion unit 13, and an image processing unit of a selector 14, an audio processing unit (not shown), and a conference processor 15. There is. The distribution unit 11, the image selection unit 12, and the sound processing unit have been described in the section of the related art, and thus description thereof will be omitted here.

The character insertion unit 13 has the same circuit 131 for each terminal accommodating channel of the video conference apparatus 10, receives the output of the image selecting unit 12 to be transmitted to each terminal accommodating channel, and outputs the output to the selector 14. Connecting. The character insertion unit 13 receives instructions such as character information and graphic information from the conference processor 15, creates an image in which information such as characters is embedded in the television image output by the image selection unit 12, and outputs the image.

The selector 14 receives the output image of the image selection unit 12 and the output image of the character insertion unit 13 and switches between the television image and the character insertion image according to the switching instruction of the conference processor 15.

The conference processor 15 will be described later with reference to FIG.

The exchange 20 has an exchange bus 21, a line interface section 22, and an exchange processor 23.

The exchange bus 21 connects the conference terminals accommodated in the line interface unit 22 and is connected to each channel connected to the video conference apparatus 10 under the control of the exchange processor 23.

The exchange processor 23 sequentially connects the conference terminals participating in the conference to the respective channels of the video conference apparatus 10 via the exchange bus 21 prior to the start of the conference. The exchange processor 23 connects to the distribution unit 11 of the video conferencing apparatus 10 if the channel is available even in response to a conference participation request from a telephone terminal that does not have a video camera.
The text information of the telephone terminal is notified to the conference processor 15 as voice channel (CH) information.

Since the character information is displayed on the screen, not only ordinary simple information but also detailed character information is stored in the video conference device 10 from the conference organizer at the time of participation in the conference, and converted into voice CH information from the exchange processor 23. , Conference processor 1
5 can also be added and output.

Next, the operation procedure of the conference processor 15 will be described with reference to FIG. 2 and FIG.

First, since the conference processor 15 receives the sound pressure information from the voice processing section (S101), it selects one of the channels (CH) having the highest sound pressure level (S102). When the selected new selected channel (CH) changes from the selected channel (CH) last instructed to the image selection unit 12 (S103), the conference processor 15 checks the audio channel information received from the exchange processor 23 (S104). ).

In step S104, the conference processor 15
If the newly selected channel is not in the audio channel information and there is image output, the TV image received from the newly selected channel (CH) is connected to a channel other than the newly selected channel (CH), and the TV image up to that time is displayed. The switching (S105) is instructed to the image selection unit 12 by the selected channel information, and the switching instruction of the selector 14 selects the output of the image selection unit 12 as in the conventional case.

FIG. 3 is a connection diagram showing an example of the state of the distribution unit 11. That is, at the end of the procedure of FIG. 2, the camera image of the new speaker 32 is transmitted to all other conference terminals,
Last speaker 3 who was connected to new speaker 32
The camera image from 1 is received.

In this state, the procedure proceeds to steps S101 to S104, and when the channel of the terminal which does not output the image included in the audio channel information is selected, the conference processor 15 inserts the character information of the terminal in the newly selected channel (CH) into characters. The image is transmitted to the unit 13, the selector 14 is instructed to switch, and the image in which characters are inserted in the output of the image selection unit 12 is output.

In this case, there is no change in the selective connection of the image selection unit 12 of FIG. 3, but the new speaker 32 is the final speaker,
The final speaker 31 is changed to the last speaker before the final speaker.

In this embodiment, the character insertion circuits 131 are required for the number of channels participating in the conference. In addition, when the conference terminals use digital transmission methods such as high-efficiency coding such as compression coding of TV image information, the character insertion means in the TV conference device on the transmission line is converted to analog and then the characters are inserted. It is necessary to provide means for inserting and digitally encoding, which further impairs economic efficiency.

Next, a second embodiment which solves these problems will be described with reference to FIGS.

FIG. 4 is a functional block diagram of a specific conference terminal showing the second embodiment of the present invention. As shown in FIG. 4, the specific conference terminal includes a television camera 41, a selector 42, an image codec 43, a demultiplexing unit 44, a line interface unit 45, a D channel processing unit 46, a character insertion unit 47, and an image display unit 48. is doing.

The image output of the television camera 41 is input to the selector 42 together with the image information sent to the image display unit 48 for display, and the output of the selector 42 is connected to the demultiplexing unit 44 via the image codec 43. The demultiplexing unit 44 multiplexes the image information and the audio information to make the line interface unit 4
5, while separating the image and audio information from the line interface unit 45 and connecting to each codec.

When the channel structure "23B + D" according to CCITT Recommendation I series is adopted for the subscriber line, the line interface unit 45 provides 1B channel for voice, 6 channels for TV image, and character information displayed on the screen. Each is transmitted on the D channel.

The D channel processing unit 46 extracts the information carried on the D channel from the line interface unit 45 and outputs the character information to be displayed on the screen to the character insertion unit 47, and controls the selector 42 when the telephone terminal speaks, for example. The television image in which the characters have been inserted is output to the image codec 43 via the selector 42. The character insertion unit 47 creates and outputs image information in which the character information is inserted in the entire image information output of the image codec 43, and outputs the image information to the screen display unit 48.

FIG. 5 is a connection diagram showing an example of a connection state of television image information when the conference terminal 34 becomes a speaker. As shown in FIG. 5, the conference terminal 34 that is the speaker, the conference terminal 35 that is the old speaker, and the specific conference terminal 36 having the block configuration shown in FIG. 4 are accommodated in the line interface unit 22 of the exchange 50. Then, the exchange bus 21 is connected to the distribution unit 11 of the video conference device. The image information is connected to the exchange bus 21 via the image selection unit 12 from the distribution unit 11 as in the conventional case.

As in the case of FIG. 3 described in the first embodiment, the selective connection of the image selection unit 12 is such that the conference terminal 34 of the speaker is the television image of the conference terminal 35 of the old speaker, and the conference terminal of the speaker. The conference terminals 35 and 36 other than the terminal 34 receive the television images of the conference terminal 34 of the speaker, including the specific conference terminal.

FIG. 6 is a functional block connection diagram showing an example of a state changed from the state of FIG. 5 when the telephone terminal becomes a speaker. FIG. 6 is a block diagram of the second embodiment.
In the following description, the plurality of conference terminals 34 to 35 and one specific conference terminal 36 are connected to the line interface unit 22.
Is housed and connected to. For example, when the telephone terminal participating in the conference is connected to the conference terminal 35 instead of the conference terminal 35, the television image information is not transmitted from the line interface unit 22.

The exchange 50 comprises an exchange bus 21, a line interface section 22 and an exchange processor 51. The video conference device 60 also includes a distribution unit 11, an image selection unit 12, and a conference processor 61. The difference from the conventional one is the exchange processor 5 for the specific conference terminal 36.
1 and the operation of the conference processor 61.

In FIG. 6, the same elements as those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

When the exchange processor 51 receives a video conference participation request from the telephone terminal, the video conference device 60 receives the request.
The character information of the telephone terminal connected to the above is transmitted to the conference processor 61 of the video conference device 60 as voice channel (CH) information together with the connected connection channel information. When the exchange processor 51 receives the voice CH information from the conference processor 61, the exchange processor 51
The received voice CH information is transferred to the specific conference terminal 36 via 2.

Next, the conference processor 61 will be described with reference to FIG. 7 and FIG. FIG. 7 is a flowchart showing an example of the main operation procedure of FIG.

When the conference processor 61 receives the sound pressure information from the voice processing unit (S101), it selects one of the connection channels (CH) having the highest sound pressure level (S102). Change of selected selected channel (CH) (S10
3), the conference processor 61 checks whether or not image information is output from the connection destination of the newly selected CH (S104), and if there is output, the procedure exactly the same as in the first embodiment of FIG. 2 is executed. .

In step S104, when there is no image output, for example, when the telephone terminal is the new speaker, the conference processor 61 transmits the voice CH information including the character information regarding the telephone terminal of the new speaker via the exchange processor 51 to the specific conference. Transmission is performed using a predetermined channel up to the terminal 36 and a D channel in a subscriber line according to CCITT Recommendation I series (S12
1) Do.

The specific conference terminal 36, which has received the audio CH information on the D channel, inserts the character information into the television image to be received and transmits it as described with reference to FIG.
122). On the other hand, the conference processor 61 switches and connects the television image from the specific channel to the connection channel other than the specific channel of the specific conference terminal 36 (S123).
By doing so, the procedure ends, and the connection state becomes as shown in FIG.

The image of the television camera displayed is the conference terminal 34 which the specific conference terminal 36 has received, and this television image is projected on the image display section 48 (see FIG. 4) of all conference terminals. Therefore, in the conference terminal which is the source of the image received by the specific conference terminal, the characters of the voice information are projected on the self-portrait.

A third embodiment for solving this problem will be described with reference to the drawings.

FIG. 8 is a block diagram showing an example of a conference terminal according to the third embodiment of the present invention. The components shown in FIG. 8 are the same as the components of FIG. 4 shown in the second embodiment, and the same reference numerals are given to them, and detailed description thereof will be omitted. In FIG. 8, compared with FIG. 4, there is no selector,
The output of the television camera 41 is directly input to the image codec 43, while the output of the character insertion unit 47 is output to the image display unit 48.
Is not connected to the image codec 43 by looping back. The D channel processing unit 46 does not need selector control.

FIG. 9 is a connection diagram showing an example of the flow state of television image information when the conference terminal 37 is selected by the speaker. Since FIG. 9 is almost the same as FIG. 4 referred to in the second embodiment, detailed description thereof will be omitted. The difference between FIG. 9 and FIG. 4 is that a telephone terminal 39 is connected to the exchange 50 in addition to the conference terminals 37 and 38 having the configuration of FIG.

FIG. 10 shows an example of a state in which the telephone terminal 39 is selected by the speaker. As shown in the figure, the flow of image information is the same as the flow shown in FIG. 9 so far even if the speaker changes to the telephone terminal 39. That is, the conference terminal 37 that has changed to the former speaker receives the outgoing image information of the conference terminal 38 that was the previous speaker, and the terminals other than the conference terminal 37 receive the outgoing image of the conference terminal 37.

10 differs from FIG. 6 showing the second embodiment in that all conference terminals 37 and 38 have a D channel processing section 46 and a character inserting section 47 shown in FIG. 8, and an exchange processor 52. Is to transfer the voice CH information received from the conference processor 61 to all the conference terminals 34 and 35 via the D channel. Except for this difference, the second embodiment is the same as the second embodiment, and thus the same components are assigned the same reference numerals and their explanations are omitted.

Next, referring to FIG. 11 together with FIG. 11, the third
The operation of this embodiment will be described. In FIG. 11, a procedure S in which the caller's channel (CH) is changed to a conference terminal (for example) 38 capable of image transmission and the display image is switched
The steps 101 to S105 have already been illustrated and described with reference to FIGS.

In step S104, when the telephone terminal 39 incapable of image transmission becomes a new selected channel (CH), the conference processor 61 transmits the audio CH information of the new selected channel to the exchange processor 52 (S131). Voice CH
The exchange processor 52 that has received the information extracts the character information regarding the speaker from the received information, and transfers the extracted character information to the conference terminals 37 and 38 via each channel that is receiving the image (S132).

If the conference terminals 37 and 38 have the interface structure according to the CCITT recommendation I series described above, D
Channel available. All of the conference terminals 37 and 38 that have received the character information have the configuration of FIG. 4 to process the received information by the D channel processing unit 46 to extract the character information, and the character insertion unit 47 receives the extracted character information. It is inserted in the image information in the inside and displayed on the image display unit 48 (S13
3) Let it go.

Of the above embodiments, the image selection section 1 shown in FIG.
2 has been illustrated and described so as not to have the connection of the image information to the telephone terminal having no image display function, but in order to simplify the processing, the image information is transferred to all the channels and is processed by the terminal. But it's okay. Although the voice CH information transfer path from the exchange to the conference terminal has been illustrated and described as the D channel,
Other methods may be used.

In order to speed up the switching during the conference and the display of the character information, the exchange processor informs the conference processor of the information as to whether the transmission / reception of the TV image of the terminal connected to the video conference device is defective or impossible as the voice CH information. It is transmitted and stored by the video conference device. Therefore, the conference processor
When the sound pressure information is received and the new selected channel is set,
It is possible to quickly and smoothly execute the image switching (or stopping) process to the terminal having the image receiving function for the newly selected channel having no image transmitting function.

Although the functional blocks are shown and described in the above embodiments, the names and arrangements of the blocks and the procedure can be changed due to the division / merging of the functional blocks, the change of the program, etc. Therefore, the present invention is limited by the above description. It is not something that will be done.

[0061]

As described above, in the multipoint video conference system according to the present invention, when a terminal (for example, a telephone terminal) that has participated in a video conference and has no image transmission function is selected as a speaker, the terminal is By transmitting predetermined TV image information and inserting character information related to a terminal that does not have an image transmission function into the TV image information received and displayed by the terminal as speaker information, it is projected on the display screen. Even when a message is sent from a terminal that does not have an image transmission function, the information about the speaker can be textually displayed without erasing the image display.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a flowchart showing an example of an operation procedure in FIG.

FIG. 3 is a connection diagram showing an example of image information in FIG.

FIG. 4 is a block diagram showing a specific conference terminal in the second exemplary embodiment of the present invention.

5 is a connection diagram showing an example of image information in FIG.

FIG. 6 is a block diagram showing a second embodiment of the present invention.

FIG. 7 is a flowchart showing an example of an operation procedure in FIG.

FIG. 8 is a block diagram showing a conference terminal according to a third embodiment of the present invention.

9 is a connection diagram showing an example of image information in FIG.

FIG. 10 is a block diagram showing a third embodiment of the present invention.

11 is a flowchart showing an example of an operation procedure in FIG.

FIG. 12 is a block diagram showing a conventional example.

[Explanation of symbols]

 10,60 TV conference device 12 Image selection unit 13,47 Character insertion unit 15,61 Conference processor 20,50 Exchange 23,51,52 Exchange processor 34-38,39 Terminal 41 TV camera 48 Image display unit

Claims (3)

[Claims] 1. A video conferencing apparatus that connects via a switch to a plurality of conference terminals having a television camera and an image display unit for displaying a television image captured by the television camera, transfers the received audio information to each conference terminal, and In a multipoint video conference system that selects the TV image of the conference terminal with the highest sound pressure level of the speaker and sends it to each conference terminal, when a request to join the video conference is received from a terminal that does not have the image information transmission function. A switching processor that connects the participation request terminal as a conference terminal to the video conference device and outputs audio channel information including both character information about the conference terminal and connection channel information to the video conference device to the video conference device. Provided in the exchange, and further included in the voice channel information received from the exchange processor. When one of the connected channels becomes the newly selected channel at the highest sound pressure level and the image switching condition occurs, the image switching procedure to this newly selected channel is stopped while the new information is added to the image information to be transmitted to each conference terminal. A multipoint video conference system comprising a video conference device for forming and inserting character information of a selected channel into a television image. 2. A video conference apparatus connected to a plurality of conference terminals having a television camera and an image display unit for displaying a television image captured by the television camera via an exchange, while transferring received voice information to each conference terminal. In a multipoint video conference system in which a TV image of a conference terminal with the highest sound pressure level of the speaker is selected and transmitted to each conference terminal, one of the conference terminals receives and displays the television image information on the image display unit. While the character information received from the exchange via a predetermined data channel is inserted and displayed on the image display unit, the image information in which the character information is inserted instead of the image of the TV camera of the own terminal via the selector is exchanged. When a request for participation in a video conference is received from a terminal that does not have the function of transmitting image information, it becomes a specific conference terminal to send to the conference request terminal. While connecting to the video conference device as a terminal and outputting audio channel information including both character information regarding the conference terminal and connection channel information to the video conference device to the video conference device, one of the audio channel information received from the video conference device is output. The exchange is equipped with an exchange processor for transmitting voice channel information to the specific conference terminal via the data channel, and one of the connection channels included in the voice channel information received from the exchange processor is newly selected at the highest sound pressure level. When the channel is set and the image switching condition occurs, the image selection to the specific conference terminal is held as it is, and the television image to the conference terminals other than the specific conference terminal is switched to the television image transmitted from the specific conference terminal. With the new processor to the exchange processor Multipoint video conference system, characterized in that with conference processor to transmit the voice channel information. 3. A video conference device connected to a plurality of conference terminals having an image display unit for displaying a television image captured by the television camera and a television image captured by the television camera through an exchange, while transferring received voice information to each conference terminal. In a multipoint video conference method in which a TV image of a conference terminal with the highest sound pressure level of the speaker is selected and transmitted to each conference terminal, all of the conference terminals receive and display the television image on the image display unit. It has a character insertion unit that inserts character information received from the exchange through a predetermined data channel into the information and outputs it to the image display unit, and requests the participation in the video conference from the terminal that does not have the image information transmission function. When received, the participation request terminal is connected to the video conference device as a conference terminal, and the character information about the conference terminal and the video conference device are connected. Audio channel information including both connection channel information to the video conferencing device is output to the video conferencing device, and one audio channel information received from the video conferencing device is transmitted via the data channel to at least all image information receiving functions. An exchange processor for transmitting to the conference terminal is provided in the exchange, and when one of the connection channels included in the voice channel information received from the exchange processor becomes the newly selected channel at the highest sound pressure level and the image switching condition occurs, A multipoint video conference system comprising: a conference processor that holds the selection of the television image of the conference terminal as it is and transmits audio channel information regarding the newly selected channel to the exchange processor.