KR20000038684A - Volume control circuit for group video conference system - Google Patents

Abstract

PURPOSE: A volume control circuit for group video conference system is provided to enable a user at the far-end to control the volume of participants by using a camera control signal. CONSTITUTION: A volume control circuit for group video conference system includes a beam former(221), a variation detector(222), a location information analyzer(223), a volume controller(224), and a sound transmitter/receiver(226). The beam former(221) receives outer sound signal and outputs voice of the required speaker selectively. The variation detector(222) detects the variation on the camera location and zoom parameters. The location information analyzer(223) receives the output signal from the variation detector(222) and detects the current location of the speaker. The volume controller(224) amplifies or reduces the output signal from the beam former by using a multiplier(225). The sound transmitter/receiver(226) transmits/receives the output signal from the multiplier(225) to/from a far-end terminal.

Description

Volume Control Circuit of Team Video Conferencing System

The present invention relates to a volume control circuit of a group video conferencing system. In particular, in a group video conference system, a far-end user uses a near-end camera angle and a zoom factor according to the position of a near-end conference participant. And a volume control circuit of a group video conferencing system for selectively concentrating and amplifying or reducing participant voices according to a final position change and a zoom size of the camera through a camera control signal controlling a zoom factor.

The group video conferencing system is a system that allows groups and groups in different regions to gather together in one place without conferences and to carry out meetings and seminars. It exchanges audio and video signals with remote people who are not in the same place. This allows you to have a conversation or meeting in the same place.

In addition, according to the number of participants in the conference, it can be classified into individual to individual, individual to many, many to many environments, and in case of a large number of parties, all people can receive video and audio through the camera and generally everyone Rather than listening to your voice, you can selectively receive video and audio from specific conference participants.

To do this, a microphone array is used to determine the speaker's left, right, top and bottom angles, adjust the camera angle and zoom accordingly, and implement an algorithm that accepts only voice signals in that direction.

As shown in FIG. 1, a general group video conferencing system is composed of microphones for transmitting a plurality of conference participants and their voices in the center, and a camera is installed behind the set-top box for video images.

In addition, the inside of the centrally installed microphone is used to find out the direction when the camera wants to illuminate only the speaker who is speaking without the whole conference attendant in the form of a microphone array composed of a plurality of microphones.

Thus, beamforming corresponding to spatial filtering in the direction may be performed to receive only the voice in the direction, and may be used only as an original function of collecting the voice which is the original purpose.

In addition, the camera installed on the set-top box can be moved left and right by installing a motor, such as a motor therein, and the zoom function can also look closer to the subject in the distance.

The dynamic function of such a camera is essential in a group video conferencing system environment where several people's appearances are reflected by a single camera.

Here, the protocol used in the local area network or the Internet when transmitting data is H.323, and the protocol used in the integrated services digital network is H.320. For example, H.324 is used as the protocol used in public switched telephone networks.

Fig. 2 is a block diagram showing the structure of a conventional group video conferencing system, which includes a far-end terminal 1 for receiving actual video and audio of a speaker and transmitting a position control signal of a camera 31; The far-end terminal 1 receives the position control signal of the camera 31, adjusts the position of the camera 31, and consists of a near-end terminal 2 for transmitting the video and audio of the actual speaker. 1) and the near-end terminal 2 are composed of sound units 10 and 39 and an image unit 20 and 40, respectively.

The image unit 20 of the far-end terminal 1 includes an input unit 21 for receiving a camera position adjustment signal; A first camera controller 22 for converting an analog signal of the input unit 21 into a digital signal; A first code converter (23) for converting a camera control signal of the first camera controller (22) to conform to a camera control protocol; And a first transceiver (24) for transmitting and receiving the output signal of the first code converter (23), wherein the sound unit (10) comprises: a first sound transceiver (12) for transmitting and receiving sound data; It is composed of a speaker 11 for transmitting the output data of the first sound transceiver 12 to the outside.

In addition, the video unit of the near-end terminal 2 and the second transceiver 34 for transmitting and receiving a camera control signal with the first transceiver 24 of the far-end terminal (1); A second code converter (33) for outputting a camera control signal conforming to the camera control protocol through the second transceiver (34); It is composed of a second camera controller 32 for controlling the camera 31 by converting the output signal of the second code converter 33 into an analog signal, the sound unit 40 is a plurality of microphone (M1 ~ M3) A beamformer 41 for receiving an external sound signal through the combination and selectively outputting a voice of a desired speaker; An environment measuring device 42 which amplifies or attenuates the output signal of the beam former 41 through a multiplier 43 according to the environment elements; It consists of a second acoustic transceiver 44 for transmitting and receiving the output signal of the multiplier 43 to the far-end terminal 1, it will be described in detail with reference to FIG.

First, the user of the far-end terminal 1 side moves the direction of the camera 31 of the near-end terminal 2 side in the situation of communicating with each other by setting up a call between two regions, and the other subject on the near-end terminal 2 side. When operating the set-top box or the remote control to see the first camera controller 22 digitalizes the analog information input by the user and outputs to the first code converter 23.

Accordingly, the first code converter 23 converts the digital output signal of the first camera controller 22 into a communication protocol that conforms to the videoconferencing network characteristics as shown in FIG. 3.

The operation message is consistent in one direction and starts with the start message, indicates continuous movement through the continuous message, and stops the movement with the stop message.

For example, if the camera 31 is moved three times to the upper right, a start message (00000001) first comes in, the message moves to the right and up (11110000) is applied and the camera moves one time to the upper right, and then stops for 400 msec. Message is authorized as shown in FIG.

Thereafter, as shown in (b) of FIG. 3, a continuous message (00000010) and a right and up moving message (11110000) are applied to move the camera 31 for the second time to the upper right, and then to keep the message (00000010) again. ) And the right and up moving messages 11110000 are applied to move the camera 31 up and down the third time.

Then, as shown in FIG. 3C, a stop message (00000011) is applied to stop the operation.

The operation messages as described above are sequentially transmitted to the first transceiver 24. Accordingly, the transceiver 24 uses the protocol corresponding to the data link layer to the second transceiver 34 on the near-end terminal 2 side. Will send the data.

In addition, the second transceiver 34 outputs data received by the first transceiver 24 to the second code converter 33, and the second transceiver 34 in the second code converter 33. Is converted into a camera control signal conforming to the communication protocol.

Therefore, the second camera controller 32 receives the output signal of the second code converter 33 to control the position of the camera 31.

At this time, the beamformer 41 receiving the external sound from the plurality of microphones M1 to M3 selectively outputs the desired speaker's voice by combining them, and the ambient environment measurer 42 is a multiplier according to the environment element. 43 amplifies or attenuates the output signal of the beamformer 41 and outputs the amplified signal.

Accordingly, the second acoustic transceiver 44 which receives the output signal of the multiplier 43 transmits it to the first acoustic transceiver 12 using a protocol corresponding to the data link layer, and receives the first acoustic transceiver 12. The audio transceiver 12 outputs it to the outside through the speaker 11.

By beamforming an external signal input through a conventional microphone as described above, and selectively outputting a desired speaker's voice, the speaker's output is self-measured according to the conditions of the external environment. There was a problem that is difficult to implement because of a complex algorithm to solve the malfunction.

Accordingly, the present invention has been made to solve the above-mentioned conventional problems. In the group video conferencing system, the far-end user uses the camera control signal to control the near-end camera angle and zoom factor according to the position of the near-end conference participant. It is an object of the present invention to provide a volume control circuit of a group video conferencing system for selectively concentrating and amplifying or reducing participant voice according to a final position change and a zoom size of a camera.

1 is a schematic diagram showing the configuration of a general group video conferencing system;

2 is a block diagram showing the structure of a conventional group video conferencing system.

3 is a view illustrating an operation message of a code converter in FIG. 2;

4 is a block diagram showing the configuration of the present invention group video conferencing system.

FIG. 5 is a two-dimensional plan view of a participant's position change around the camera in FIG. 4; FIG.

*** Description of the symbols for the main parts of the drawings ***

100: fabric terminal 110,210: sound unit

120, 220: image portion 221: beam former

222: change amount measuring instrument 223: location information analyzer

224 volume control 225 multiplier

226: Acoustic Transceiver

A configuration of the present invention for achieving the above object is a beamformer for receiving an external sound signal through a plurality of microphones and selectively outputs the desired speaker's voice by combining them according to the current speaker's position; A change amount measuring unit for detecting a position change and a zoom factor of the camera; A positional information analyzer which receives an output signal of the change amount measurer and detects a current position of the speaker; A volume controller for amplifying or attenuating the output signal of the beam former through a multiplier according to the output signal of the position information analyzer; Characterized in that it consists of an audio transceiver for transmitting and receiving the output signal of the multiplier to the far-end terminal.

Hereinafter, with reference to the accompanying drawings, the operation and effect of an embodiment of the present invention will be described in detail.

4 is a block diagram showing a configuration of a group video conferencing system of the present invention, and the present invention provides a plurality of microphones M1 in the sound unit 220 of the near-end terminal 200 in the configuration of the conventional group video conferencing system shown in FIG. A beamformer 221 for receiving an external sound signal through -M3) and selectively outputting the desired speaker's voice by combining the signals according to the current speaker's position; A change amount measurer 222 for detecting a position change and a zoom factor of the camera 211; A position information analyzer 223 which receives the output signal of the change amount measuring instrument 222 and detects the current position of the speaker; A volume controller 224 for amplifying or attenuating the output signal of the beamformer 221 through a multiplier 225 according to the output signal of the position information analyzer 223; It comprises a sound transceiver 226 for transmitting and receiving the output signal of the multiplier 225 to the far-end terminal 100, the operation process according to the invention configured as described above will be described with reference to the two-dimensional plan view of FIG.

First, when the first camera 211 is zooming the speaker at the first position P1 in FIG. 5 to fit a specific size of the screen, the position vector dP1 of the first position may be obtained. Further, the position vector dMP1 of the first position P1 from the microphone array is obtained from the difference signal between the position vector dP1 and the position vector dM of the microphone.

Therefore, the beamformer 221 forms the beam in the direction of the first position P1 according to the angle thereof, and adjusts the microphone gain according to the distance.

In addition, the user of the far-end terminal 100 moves the direction of the camera 211 of the near-end terminal 200 in a situation in which the two terminals communicate with each other through call setup. When operating the set-top box or the remote control to see, the first camera controller 122 digitalizes the analog information input by the user and outputs to the first code converter 123.

Accordingly, the first code converter 123 converts the digital output signal of the first camera controller 122 into a communication protocol that conforms to the videoconferencing network characteristics, and then converts the digital output signal from the first camera controller 122 to the near-end terminal 200 through the first transceiver 124. To a second transceiver 214.

The second transceiver 214 outputs the data received by the first transceiver 124 to the second code converter 213, and the second code converter 213 of the second transceiver 214. The output signal is converted into a camera control signal conforming to the communication protocol.

Accordingly, the second camera controller 212 extracts analog data for driving the camera from the output signal of the second code converter 213 to drive the camera 211.

At this time, the change amount measuring unit 222 receiving the plurality of operation messages of the second camera controller 212 stores the direction of the operation message (Pan: left and right, Tilt: up and down, Zoom: perspective) and maintains the same direction until the stop message. The direction of the operation message is obtained by examining the number of continuous messages having the same.

In addition, the location information analyzer 223 receives the output signal of the change amount measuring unit 222 to know the updated user's position P2, and adjusts the camera angle therefrom. By have a certain size of the screen.

Therefore, the position vector dMP2 of the second position P2 from the microphone array is obtained from the difference signal between the second position vector dP2 and the position vector dM of the microphone.

Therefore, according to the angle, the beamformer 221 forms a beam in the direction of the second position P2 through the electronic signal processing of the signals input to the plurality of microphones, and adjusts the microphone gain according to the distance.

Here, the volume controller 224 receives a zoom factor of the camera 211 to view the near end speaker's image larger or smaller by the far-end user, and detects the difference value dz from the previous zoom value by the auto zoom function. When looking closer through the auto-zoom function, the difference value has a positive value and increases the gain, and when viewed far away, the difference value has a negative value and lowers the gain.

That is, since the auto-zoom function of the camera 211 has an ideal value, the auto zoom function has a difference by 3 decibels for each level, and when the level is increased by one level, the volume controller corresponds to a value of +3 decibels (2 ^1/2 ). Multiply the output signal of the beamformer 221 by the multiplier 225, so that the acoustic signal transmitted through the second transceiver 226 is 3 decibels larger.

Therefore, the first acoustic transceiver 112 that receives it outputs it to the outside through the speaker 111.

As described in detail above, the present invention provides the user according to the final position change and the zoom size of the camera through a camera control signal for controlling the far-end camera angle and the zoom factor according to the position of the near-end conference participant in the group video conferencing system. By selectively concentrating and amplifying or reducing the participant's voice, the voice signal is concentrated and amplified only by the conversion factor of the near-end camera moved by the far-end conferee, and the efficiency is improved. Meetings are possible.

In addition, the far-end conference control the size of the voice of the near-end party through the change of the zoom factor of the camera sent by the far-end conference, it is effective to provide a comfortable meeting environment by adjusting the volume of the speaker according to the subjective auditory characteristics of the receiver.

Claims (5)

A beamformer for receiving an external sound signal through a plurality of microphones and selectively outputting a desired speaker's voice by combining them according to the current speaker's position; A change amount measuring unit for detecting a position change and a zoom factor of the camera; A positional information analyzer which receives an output signal of the change amount measurer and detects a current position of the speaker; A volume controller for amplifying or attenuating the output signal of the beam former through a multiplier according to the output signal of the position information analyzer; And a sound transceiver for transmitting and receiving the output signal of the multiplier to the far-end terminal. The group video conferencing system according to claim 1, wherein the change amount specifier stores the direction of the camera operation message, and detects the position change of the camera and the zoom factor by examining the number of continuous messages having the same direction until the stop message. Volume control circuit. The volume control circuit of claim 1, wherein the position information analyzer calculates a position vector of the speaker according to a change in the position of the camera to detect a position vector between the current position of the speaker and the microphone. The multiplier of claim 1, wherein the volume controller receives a zoom factor of a camera for viewing a near end speaker's image larger or smaller by a far-end user to detect a difference value from a previous zoom value to control an amplification gain level of the multiplier. A volume control circuit of a group video conference system. The multiplier according to claim 4, wherein the volume controller transmits an output signal of the beamformer by greatly adjusting the amplification gain level of the multiplier when looking closer through the auto zoom function, and down-adjusting the amplification gain level of the multiplier when viewing the distance And transmits the output signal of the beamformer to a smaller level.