JP2700513B2 - Video conference system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video conference system in which two conference rooms in remote places are connected by a transmission line, and the state of the conference rooms can be mutually recognized by video and audio.
Local area network (LA) in one area
The present invention also relates to a system in which the state of a conference can be monitored and observed in another conference room of the same building or a different building connected in N).

[0002]

2. Description of the Related Art Conventionally, a video conference system (video conference) in which two remote conference rooms are connected by a data line, and the video and audio of the other conference room are displayed and amplified in their own conference room. System) is known. In this video conference system, a TV conference terminal device is installed in a conference room at each location, the TV conference terminal devices are connected by a dedicated data line, and a television receiver, a television camera, and a microphone are connected to the TV conference terminal device. It is a system that did.

[0003]

Therefore, in this video conference system, video and audio can be mutually exchanged only between two conference rooms at two remote locations, and a conference between two conference rooms can be performed in another room. Could not be monitored and observed. In order to solve this, there is a method in which a received signal in one conference room is transmitted as it is to another room via a cable and displayed on a television receiver in that room. However, according to this method, even if the state of the conference room in the other party's ground can be seen, the state of the conference room in the local area and the conversation cannot be heard, and it is difficult to grasp the progress of the conference. is there. Further, it is conceivable to transmit a transmission signal and a reception signal of a conference room at the own location to another room. However, there is a problem in equipment that requires two transmission lines and two television receivers. There is. When monitoring and listening to the state of a meeting, it is sufficient if both sounds can be observed and the image can be grasped from one of the meeting rooms. Further, there is a problem that the two conference rooms are fixed in the building. That is, since the TV conference terminal device cannot be easily moved due to the weight of the device and connection to a dedicated data line, a problem arises in that a room dedicated to a video conference is fixed in a building on one side. is there.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has as its object to monitor the state of a meeting even in a room other than the video conference room, to observe both parties' conversations, and , Video conference room can be easily changed.

[0005]

According to an aspect of the present invention, a terminal device at a first location and a terminal device at a second location are connected by a bidirectional transmission line, and the first and second terminal devices are connected to each other. In a video conference system in which video and audio in a conference room in a second location can be mutually recognized in a conference room in a second location and in a conference location in a first location, a frequency division multiplexing transmission method is used. A broadband local area network (LAN) that enables signals to be transmitted bidirectionally using a plurality of uplink channels, and a video and audio signal of a downstream first channel of the LAN to be demodulated and transmitted by a terminal device at a first location. A first demodulator that generates a signal to be provided to an input terminal, and a video and audio signal received from a second terminal device output from a reception output terminal of the first terminal device, and modulated. Up 2nd cha A first modulator for outputting to the LAN, a second demodulator connected to the LAN for demodulating the video and audio signals of the downstream second channel, and a video signal output from the second demodulator. A video display device for displaying video, a voice generating device for generating voice in response to a voice signal output from the second demodulator, and a voice capturing device for capturing voice in a conference room at the first location and converting the voice into a voice signal. A sound device, a mixer that mixes an audio signal output from a sound pickup device and an image pickup device that captures an image of a conference room in a first place, and an audio signal output from a second demodulator, and an output of the image pickup device enter the audio signal output of the video signal and the mixer which, as a signal of the uplink first channel, and a second modulator for outputting to the LAN, the first ground conference
Room is provided in a separate room,
Network and connected to the downlink first channel signal or
Is an audio-video display device that can demodulate the downlink second channel signal.
Is provided.

In another aspect of the present invention, an audio signal output from a first demodulator and an audio signal output from a reception output terminal of a terminal device are input, and an audio signal output from the first demodulator is input. And an echo canceling device for outputting, to a transmission input terminal of the terminal device, an audio signal from which a signal having the same component as the audio signal output from the reception output terminal of the terminal device is eliminated.

According to another aspect of the present invention, in the first aspect, an audio signal output from the second demodulator and an audio signal output from the sound collection device are input, and the audio signal output from the sound collection device is further input. And an echo canceller for outputting an audio signal obtained by eliminating a signal having the same component as the audio signal output from the second demodulator to the mixer as an output signal from the sound pickup device.

[0008]

The terminal device of the video conference system comprises a first demodulator,
It is connected to the LAN via the first modulator. That is, the first demodulator demodulates the downstream first channel video signal A and audio signal a + b of the LAN, and inputs the demodulated signals A, a + b to the transmission input terminal of the terminal device. The video signal B and the audio signal b output from the reception output terminal of the terminal device (the video signal and the audio signal transmitted from the conference room at the second location)
Is modulated by the first modulator into an uplink second channel signal B / b and output to the LAN.

[0009] In the video conference room in the first place, a video display device, a sound generation device, a sound collection device, an imaging device, a second demodulator,
A second modulator and a mixer are provided. The second demodulator is L
The signal of the downstream second channel of the AN is demodulated to produce a video signal B,
An audio signal b is obtained. The video signal B is input to the video display device, and the state of the conference room at the second location is displayed as a video. The audio signal b is output from the audio generator, and the audio b in the conference room at the second location is amplified in the conference room at the first location.

Also, the audio signal a obtained by the sound pickup device and the second
The audio signal b demodulated by the demodulator is mixed by the mixer. Then, the audio signal a + b output from the mixer
And the video signal A of the conference room at the first place obtained by the imaging device
Is input to the second modulator, and the signal A of the upstream first channel is
/ A + b and output to the LAN.

As a result, in the separate rooms I and II where the LAN of the first location is provided, if the first channel is received by the television receiver, the image A of the conference room of the first location is viewed. Thus, it is possible to simultaneously observe the sound a of the conference room in the first location and the sound b of the conference room in the second location. When the second channel is received by the television receiver, the user can watch the image B of the conference room in the second place and observe the sound b in the conference room in the second place.

An echo for inputting the audio signal a + b output from the first demodulator and the audio signal b output from the reception output terminal of the terminal device, and eliminating a signal having the same component as the audio signal b from the audio signal a + b. When the canceling device is provided, the output from the echo canceling device is the audio signal a of the conference room at the first location.
Becomes This audio signal a is input to the transmission input terminal of the terminal device. As a result, the audio signal b of the conference room at the second location is not returned to the second location.

An audio signal b output from the second demodulator,
Enter the audio signal a + b ^`to output the sound collection device, the output echo canceller that outputs the audio signal to erase the voice signal and the signal of the same component that the output of the second demodulator from the audio signal to the sound pickup device When the audio signal output from the echo canceller is input to the mixer, it is possible to prevent the audio signal b of the conference room in the second place from sneaking into the sound pickup device from the audio generation device. it can. Therefore, echo howling is further prevented.

[0014]

According to the present invention, the video signal B and the audio signal b of the second place received by the terminal device are modulated into the signal of the second channel and transmitted to the LAN, and the video signal B and the audio signal b are set in the video conference room. The audio signal a output from the audio device and the audio signal b obtained by demodulating the signal of the second channel are mixed, and the mixed audio signal a + b and the video signal A output from the imaging device are modulated. This is a system for transmitting to the first channel of the LAN. Therefore, the terminal device of the video conference system,
Since it is connected to the video conference room via the LAN, it can be located at another place. That is, it becomes easy to move or change the video conference room to an arbitrary room in a building, for example, where a LAN is provided, separately from the fixed location of the terminal device. For example, in another room in the building where the LAN is provided, for example, the image A of the conference room in the first place and the first
And the sound b of the conference room in the second place can be simultaneously observed. Further, it is possible to observe the video B and the audio b in the conference room in the second place.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to a specific embodiment. First Embodiment FIG. 1 is a block diagram showing a configuration of a video conference system in a first location. In the building where this system is installed, a local area network (hereinafter referred to as "LA
N ". 2) are provided. The LAN 2 is a transmission line based on the frequency division multiplexing transmission method, and has a plurality of low-bandwidth uplink channels for transmitting information to the headend 1 and a high-bandwidth band for transmitting information from the headend 1 to the terminal. It has a plurality of downlink channels. The head end 1 has a frequency conversion function of converting an uplink channel signal into a downlink channel signal.

A terminal installation room 10 is provided in one fixed place of the building where the LAN 2 is installed. The terminal device installation room 10 is provided with a demodulator 12 (first demodulator) for demodulating the signal of the downlink first channel of the LAN 2, and the video signal A and the audio signal a + b demodulated by the demodulator 12 are provided. , And video and audio transmission input terminals of the TV conference terminal device 11. TV conference terminal device 11
Are connected by an ISDN line 3 to a TV conference terminal device of the same configuration provided in the conference room at the second location. From the reception output end of the TV conference terminal device 11, a video signal B and an audio signal b from the conference room at the second location are output.

On the other hand, a video conference room 30 separate from the terminal device installation room 10 has a demodulator (second demodulator) 31 for demodulating a signal of the second channel going down from the LAN 2 and a video conference room 30. And a modulator (second modulator) 34 for modulating the video and audio of the first channel into a first channel signal and outputting the signal to the LAN 2. The video signal B demodulated by the demodulator 31 is output to the TV receiver 32, and the video of the conference room at the second location is displayed. The audio signal b demodulated by the demodulator 31 is input to the speaker 33 and output as audio.

On the other hand, an audio signal a obtained by being picked up by the microphone 36 and an audio signal b demodulated by the demodulator 31 are input to a mixer 37, where the two signals are mixed.
The audio signal a + b output from the mixer 37 and the TV camera 35
Is input to the modulator 34, and the modulator 34 outputs the signal A / a + b of the first channel.
And is output to LAN2.

The first channel of the LAN 2 is a channel for transmitting the video signal A and the audio signal a in the video conference room 30 at the first location. The second channel is a channel for transmitting the video signal B and the audio signal b of the conference room at the second location. However, the audio signal b of the conference room in the second location obtained by demodulation by the demodulator 31 and the audio signal a of the conference room in the first location are mixed and output to the first channel. The audio signal of one channel is an audio signal a and an audio signal b
Are mixed.

Therefore, the separate room 4 connected to the LAN 2
In the TV receivers 41 and 51, which are audio / video display devices installed at 0 and 50, if the first channel is received, the video A of the first place can be received and the audio of the conference room of the first place can be received. a and the mixed sound of the sound b of the conference room at the second place. In addition, if the second channel is received, the user can view the video B of the conference room in the second location and can hear the sound b in the conference room in the second location.

As described above, in this embodiment, the video conference room 3
Since the demodulator 31 and the modulator 34 at 0 are connected to the LAN 2 and the TV conference terminal device 11 is connected to the LAN 2 via the demodulator 12 and the modulator 13, the terminal device installation room 10 is fixed. Even if it is impossible to move, the video conference room 30 can easily move to any room where the LAN 2 is laid.

Second Embodiment FIG. 2 shows the configuration of a system according to a second embodiment. Devices having the same functions as in the first embodiment are given the same numbers. In this embodiment, an echo canceller 14 is provided in the terminal device installation room 10. The echo canceler 14 outputs the audio signal a + b output from the demodulator 12.
Is input from the input terminal (IN), and the TV conference terminal device 11 is input.
The audio signal b output from the reception output terminal of the reference terminal (r
ef). Then, a signal having the same component as the audio signal b is deleted from the audio signal a + b, and the deleted audio signal a is output from the output terminal (OT) to the transmission input terminal of the TV conference terminal device 11. Thus, the audio signal b generated in the conference room at the second location is not returned to the conference room at the second location. Therefore, echo in the conference room at the second location is prevented.

Third Embodiment FIG. 3 shows the configuration of a system according to a third embodiment. In the video conference room 30, in order to prevent the echo caused by sound b ^`output from the speaker 33 is input to the microphone 36, the echo canceller 38 is provided. The echo canceler 38 has a reference terminal (ref)
The audio signal b demodulated by the demodulator 31 is input to the speaker 33, and the audio signal b output from the reference terminal (ref) is input to the speaker 33. The output of the microphone 36 is input to the input terminal (IN) of the echo canceller 38, and the output from the output terminal (OT) is output to the mixer 37.

With this configuration, a pseudo echo signal is generated based on the audio signal b output from the demodulator 31, and the signal is eliminated from the audio signal output from the microphone 36, so that only the audio signal a by the speaker is output. Is obtained. Then, the audio signal a is input to the mixer 37. Exactly first
The audio signal a of the conference room at the second location and the audio signal b of the conference room at the second location are mixed. Thereby, the separate room 40,
When listening at 50, an audible sound with no echo is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a video conference system according to a first embodiment.

FIG. 2 is a block diagram showing a configuration of a video conference system according to a second embodiment.

FIG. 3 is a block diagram showing a configuration of a video conference system according to a third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Head end 2 ... LAN 10 ... Terminal device installation room 14 ... Echo canceller 30 ... Video conference room 37 ... Mixer 38 ... Echo canceller

 ──────────────────────────────────────────────────続 き Continuing from the front page (73) Patent holder 000004226 Nippon Telegraph and Telephone Corporation 3-19-2 Nishi Shinjuku, Shinjuku-ku, Tokyo (72) Inventor Shinzo Mizuno 5-37-8 Shiba 5-chome, Minato-ku, Tokyo Hibiya Sogo Equipment Co., Ltd. (72) Inventor Togoro Abe 2--24-18 Chiyoda, Naka-ku, Nagoya City, Aichi Prefecture Inside Aichi Electronics Co., Ltd. No. 6 Inside Cast Co., Ltd. (72) Inventor Kunio Suzuki 1-6, Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation

Claims (3)

(57) [Claims] A video and audio signal relating to a conference room at a first location is input from a transmission input terminal and transmitted to a terminal device at a second location, and a video and audio signal relating to a conference room at a second location is received. And a terminal device installed at the first location, which receives the video and audio signals from the reception output terminal, and a terminal device installed at the second location, are connected via a bidirectional transmission path. 1st and 2nd
In a video conference system in which video and audio in a conference room in a second place can be mutually recognized in a conference room in a second place and a first place, a frequency division multiplexing transmission system formed at least in the first place The signal can be transmitted bidirectionally using a plurality of downlink channels in which signals are transmitted from the head end to the terminal and a plurality of uplink channels in which signals are transmitted from the terminal to the head end. A broadband local area network, and a first demodulator that demodulates a video and audio signal of a downlink first channel of the local area network to generate a signal to be supplied to a transmission input terminal of a terminal device at a first location. Modulating the video and audio signals received from the terminal device at the second location output from the reception output terminal of the terminal device at the first location, Ri as a second channel signal, a first modulator for outputting to said local area network, is connected to the local area network, the downlink second
A second demodulator that demodulates the video and audio signals of the channel, a video display device that displays video based on the video signal output by the second demodulator, and a video signal that is output by the second demodulator. A sound generation device that generates sound, a sound pickup device that picks up sound in the conference room in the first place and converts the sound into an audio signal, and an image pickup apparatus that captures an image of the meeting room in the first place. A mixer for mixing an audio signal output from the sound pickup device and an audio signal output from the second demodulator; and a video signal output from the imaging device and the audio signal output from the mixer. And a second modulator for outputting to the local area network as a signal of an uplink first channel, and a second modulator provided in a separate room with respect to the conference room in the first location,
It is connected to the broadband local area network
The downlink first channel signal or the downlink second channel
A video conference system comprising: an audio-video display device capable of demodulating a channel signal . 2. An audio signal output from the first demodulator and an audio signal output from a reception output terminal of the terminal device are input, and the audio signal output from the first demodulator is input from the audio signal. 2. The terminal according to claim 1, further comprising: an echo canceller that outputs an audio signal obtained by eliminating a signal having the same component as an audio signal output from a reception output terminal of the terminal device to a transmission input terminal of the terminal device. Video conference system. 3. An audio signal output from the second demodulator and an audio signal output from the sound pickup device are input, and an audio signal output from the sound pickup device is input to the second demodulator. 2. The video conference system according to claim 1, further comprising: an echo canceller that outputs an audio signal from which a signal having the same component as the output audio signal has been deleted to the mixer as an output signal from the sound collection device. 3.