JPH04312036A - Television conference system - Google Patents

Abstract

PURPOSE:To curtail transmission cost in a television conference system by changing the quantity of the picture transmission of a participant of the television conference as occasion demands. CONSTITUTION:The importance of sound data quantity is evaluated by a sound data evaluating means 5a, and if a transmission line 3 need be changed, line terminal equipment 2 is controlled by a controller 6 so as to secure the new transmission line. Further the controller 6 controls a picture encoder 41a into a picture compression ratio corresponding to the data quantity of the new transmission line. Thus, the quantity of the picture transmission of the participant of the television conference is changed as occasion demands, and the data transmission cost in the whole television conference system can be curtailed. For instance, when the picture data quantity is small, a low-speed transmission line is selected.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television conference system that connects remote locations through video and audio communications, and more particularly to a television conference system in which image signals are encoded and transmitted through a digital transmission path.

0002

[Prior Art] A television conference system is a system that connects remote locations through video and audio communications, allowing everyone to hold a conference in an atmosphere as if they were holding the conference at the same location while viewing the other party's screen. It is. One of the benefits of this system is that it can save travel time, travel costs, and accommodation costs for attendees who are far away.

The television conference system is mainly composed of a plurality of television conference terminal devices 1, line termination devices 2, and transmission lines 3 distributed at different locations, as shown in FIG. The television conference terminal device 1 includes a television camera 11
, a monitor 12, a microphone 13, a speaker 14, etc. In addition to the above components, the television conference terminal device 1 may include a facsimile input/output device, a still image input/output device, a character input/output device, a handwritten character input/output device, and the like. The line termination device 2 is a device that matches the interface between the television conference terminal device 1 and the transmission line 3. The transmission path 3 is a bidirectional transmission path for data communication that connects each line termination device 2. While image information generally has an extremely large amount of information, it also contains a considerable amount of redundant components. Therefore, in order to remove the redundant components of the original image signal, encoding/coding is performed between the television conference terminal device 1 and the line termination device 2. Currently, it is common to digitize the input signal via the decoding device 4 and perform compression encoding processing. This encoding/decoding device 4 includes an image encoding device 41 that encodes an image, an image decoding device 42 that decodes encoded image data, an audio encoding device 43 that encodes an audio signal, and an audio encoding device 43 that encodes an audio signal. It is comprised of an audio decoding device 44 that decodes the received audio data.

[0004] The operation of the above configuration will be explained below. First, an image signal inputted by the television camera 11 is converted from an analog signal into a digital signal by the image encoding device 41, and is then converted into a digital signal by a predictive encoding method such as interframe prediction or motion compensated interframe prediction, or a transform encoding method such as discrete cosine transform. compressed using a compression method. The compressed image data is similarly sent to the line termination device 2 together with the audio signal obtained by the microphone 13 and the audio data encoded by the audio encoding device 43, and a transmission frame corresponding to the transmission speed of the transmission path 3 is sent. The signal is then assembled into two lines and sent to another line termination device 2' via the transmission line 3.

Next, the video data and audio data sent from the other line termination device 2' are decoded by an image decoding device 42 and an audio decoding device 44, respectively, and sent to the monitor 12 and speaker 14, respectively. Sent. Since the video conferencing system needs to process video and audio in real time, the amount of data transmitted per transmission frame is fixed, and the transmission is carried out over a dedicated line or line for the video conferencing system that can secure a certain amount of data. A switched public communications network is used as the transmission path.

[0006]

[Problems to be Solved by the Invention] In the conventional video conference system described above, image data is much larger than audio data even if it is compressed, so it is necessary to communicate video data throughout the conference. It is necessary to continue to secure high-speed transmission lines. However, as a characteristic of a meeting, it is not considered necessary to pay equal attention to all participants. That is, it is often necessary to pay attention only to the participant who is speaking, or to a special participant with a small number of participants. Considering the characteristics of such conferences, securing the same high-speed transmission path for transmitting images of all participants would be expensive compared to the effectiveness.

[0007] The present invention solves the above problem, and reduces the data transmission cost used in the entire video conference system by changing the amount of image transmission for participants participating in the video conference as necessary. The purpose of the present invention is to provide a video conference system that can reduce the amount of noise.

[0008]

[Means for Solving the Problems] In order to solve the above problems, the television conference system of the present invention provides an image coding system in which the compression rate of image signals from a television conference terminal that inputs and outputs images and sounds is variable. a line terminating means capable of securing transmission paths for different amounts of data transmission; a data evaluation means for monitoring the amount of audio data or the amount of image data and evaluating the importance of the image data to be transmitted; Based on the evaluation result, the circuit terminating means can be controlled to secure a new transmission path, and further, the image compression rate of the image encoding means can be controlled to correspond to the data amount of the new transmission path. and control means.

The television conference system of the present invention further includes an image encoding means having a variable compression rate for image signals from a television conference terminal that inputs and outputs images and sounds;
a line terminating means capable of securing transmission paths with different amounts of data transmission, a transmission amount selecting means capable of selecting an amount of image data to be transmitted, and a new transmission to the line terminating means based on a selection result by the transmission amount selecting means. and control means for controlling the image compression rate of the image encoding means so as to correspond to the data amount of the new transmission line.

0010

[Operation] With the above configuration, the data evaluation means monitors the amount of audio data or image data, evaluates the importance of the image data to be transmitted, and if it is necessary to change the transmission path, the control means The line terminating means is controlled to secure the transmission path, and the control means also controls the image encoding means to an image compression rate that corresponds to the amount of data on the new transmission path, so that the user can participate in the television conference. The amount of images transmitted by each participant can be changed as necessary, and the cost of data transmission used in the entire video conference system can be reduced. For example, when the amount of image data is small, a low-speed transmission path is selected, making it possible to reduce data transmission costs for the entire video conference system.

[0011]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the same reference numerals are given to those having the same functions and effects as those of the conventional example, and the explanation thereof will be omitted.

FIG. 1 is a block diagram of a television conference system showing a first embodiment of the present invention. In FIG. 1, the transmission path 3 includes a channel 31 having a different data transmission speed and a channel 32 having a lower data transmission speed than the channel 31. The encoding/decoding device 4a is composed of an image encoding device 41a whose compression rate for image signals is variable, an image decoding device 42, an audio encoding device 43a, and an audio decoding device 44. Audio encoding device 43a
The audio data measuring section 51a connected to the audio data measuring section 51a receives audio data from the audio encoding device 43a and measures the volume of the input audio data. A determining unit 52a connected to the audio data measuring unit 51a determines whether a conference participant using the television conference system is speaking based on the volume measured by the audio data measuring unit 51a. The audio data measuring section 51a and the determining section 52a described above constitute the audio data evaluation device 5a. A transmission state holding unit 61 connected to the line termination device 2 holds the transmission state. A determination unit 62 connected to the transmission state holding unit 61 and the determination unit 52a is connected to a channel control unit 63 and a compression ratio control unit 64, and is connected to the transmission state holding unit 61 and the determination unit 52a, and is connected to the transmission state holding unit 61 and the determination unit 52a. After instructing the channel control unit 63 to secure a new channel if it is necessary to change the channel of the transmission path, the compression rate control unit 64
to change the compression ratio to correspond to the transmission speed of the channel to be changed. The channel control unit 63 is connected to the line termination device 2, and controls the line termination device 2 to secure a new channel based on instructions from the channel control unit 63. The compression rate control unit 64 is connected to the image encoding device 41a, and controls the compression rate of the image signal of the image encoding device 41a in response to instructions from the compression rate control unit 64 to correspond to the data amount of the new channel. The control device 6 is constituted by the transmission state holding section 61, determination section 62, channel control section 63, and compression ratio control section 64 described above.

The operation of the above configuration will be explained below. First, an image signal input from the television camera 11 is encoded by the image encoding device 41a, compressed, and sent to the line termination device 2. Also, the audio signal input from the microphone 13 is transmitted to the audio encoder 43.
The data is sent to audio data measuring section 51a, where it is encoded and the volume is measured. The result measured by this audio data measuring section 51a is sent to the determining section 52a. This determining unit 52a accumulates the sent values for a certain period of time, and if the cumulative value is greater than a certain reference value, it considers that the video signal input from the television camera 11 is of high importance. The determining unit 62 of the control device 6 compares the value held in the transmission path status holding unit 61 with the importance information from the determining unit 52a, and determines whether the channel of the transmission path needs to be changed by the channel control unit. 63. In response to this, the channel control unit 63 instructs the line termination device 2 to change to a new channel. In response to instructions from the channel control unit 63, the line termination device 2 secures the channel 32, for example, assuming that the channel 31 is secured. When the line termination device 2 succeeds in securing the channel 32, it notifies the compression ratio control section 64 via the determination section 62, and the contents of the transmission state holding section 61 are also changed. Compression rate control section 64
is the compression rate for the image encoding device 41a on the channel 32
command to change the compression ratio to correspond to the transmission speed. Then, the image encoding device 41a creates a new channel 32.
Change the image compression rate to correspond to the amount of data. and,
When the amount of data sent from the image encoding device 41a changes, the line termination device 2 starts transmitting data to the newly secured channel 32, and simultaneously terminates the connection of the other channel 31. That is, the line termination device 2 which has received the data after the compression ratio has been changed sends this data to the channel 32 and terminates the connection of the channel 31.

As described above, according to the television conference system of the first embodiment of the present invention, the input audio signal is monitored and when there is little input audio, the compression rate of the image data is increased to reduce the transmission speed. Channels are available.

FIG. 2 is a block diagram of a television conference system showing a second embodiment of the present invention. In FIG. 2, an image data measurement unit 51b connected to the image encoding device 41b receives image data from the image encoding device 41b and measures the amount of input image data. A determining unit 52b connected to the image data measuring unit 51b monitors increases and decreases in the amount of data measured by the image data measuring unit 51b, and determines the importance of the image. The above image data measuring section 51b
The determination unit 52b constitutes an image data evaluation device 5b.

The operation of the above configuration will be explained below. First, the image signal inputted from the television camera 11 is encoded by the image encoding device 41b, compressed and sent to the line termination device 2, but the encoded data is simultaneously sent to the image data measuring section 51b. The amount of data is measured. The determination unit 52b of the image data evaluation device 5b accumulates the values sent from the image data measurement unit 51b for a certain period of time, and if the value is greater than a certain standard, it considers that the video signal input by the television camera 11 is of high importance. The determining unit 62 of the control device 6 compares the value held in the transmission path status holding unit 61 with the importance information, which is the amount of change, and informs the channel control unit 63 if it is necessary to change the channel of the transmission path. Instruct. As a result, the channel control unit 63
instructs the line terminating device 2 to change the channel. For example, if the channel 31 is secured, the line termination device 2 secures the channel 32 according to instructions from the channel control unit 63. When the line termination device 2 succeeds in securing the channel 32, it notifies the compression ratio control section 64 via the determination section 62, and the contents of the transmission state holding section 61 are also changed. The compression rate control unit 64 instructs the image encoding device 41b to change the compression rate to a compression rate corresponding to the transmission rate of the channel 32. The image encoding device 41b changes the image compression rate to correspond to the data amount of the new channel 32. The line termination device 2, which has received the data after the compression ratio has been changed, sends the data to the channel 32 and terminates the connection of the channel 31.

As described above, according to the television conference system of the second embodiment of the present invention, the input image signal is monitored and when the amount of encoded image data is small, the compression rate of the image data is increased. This allows the use of slower transmission channels.

FIG. 3 is a block diagram of a television conference system showing a third embodiment of the present invention. In FIG. 3, the terminal selection unit 51c is configured to be able to select any terminal participating in the video conference. A determining unit 52c connected to the terminal selecting unit 51c determines whether the selected terminal is itself or another terminal. When the selected terminal is another terminal, the requesting section 53 connected to the determining section 52c sends the selected terminal to the electric transmission path 3.
Request a change in transmission amount via . Further, the change amount selection unit 54 is connected to the determination unit 52c, and selects the transmission amount to be changed. The above terminal selection section 51c, determination section 52c, request section 53, and change amount selection section 54 constitute the transmission amount selection device 5c.

The operation of the above configuration will be explained below. First, the terminal selection section 51c selects the terminal whose transmission amount of image data is to be changed, and the transmission amount is changed to the change amount selection section 51c.
Select by. When the terminal selected by the terminal selection section 51c is another terminal, the request section 53 is informed, and the request section 5
3 outputs a change request to the selected terminal through the transmission line 3. Furthermore, when the determining unit 52 c determines that the terminal selected by the terminal selecting unit 51 c is the terminal itself, the change amount selected by the change amount selecting unit 54 is transmitted to the determining unit 62 . The determining unit 62 compares the value held in the transmission line state holding unit 61 with the importance information, which is the amount of change, and instructs the channel control unit 63 whether the channel of the transmission line 3 needs to be changed. Thereby, the channel control unit 63 instructs the line termination device 2 to change the channel. For example, if the channel 31 is secured, the line termination device 2 secures the channel 32 according to instructions from the channel control unit 63. When the line termination device 2 succeeds in securing the channel 32, it notifies the compression ratio control section 64 of this information via the determination section 62, and the contents of the transmission state holding section 61 are also changed. The compression rate control unit 64 instructs the image encoding device 41c to change the compression rate to a compression rate corresponding to the transmission rate of the channel 32. Then, the image encoding device 41c changes the compression rate. The line termination device 2, which has received the data after the compression ratio has been changed, sends the data to the channel 32 and terminates the connection of the channel 31.

As described above, according to the video conference system of the third embodiment of the present invention, when the amount of image data is small, the transmission amount selection device 5c is used to increase the compression rate of the image data, thereby reducing the speed of the image. Transmission channels are available.

[0021] Therefore, instead of transmitting images of all participants participating in a video conference using an equally high-speed transmission line, only noteworthy images of speakers, etc. are transmitted using a high-speed transmission line. By transmitting the information, the transmission cost used in the video conference system can be saved.

[0022]

As described above, according to the present invention, the importance of the image data to be transmitted is determined by the audio data evaluation device, the image data evaluation device, or the transmission amount selection device, and the image encoding device By changing the compression rate of , and transmitting image data of low importance using a low-speed channel, it is possible to significantly reduce communication costs used for video conferencing.

[Brief explanation of drawings]

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

FIG. 2 is a block diagram of a video conference system showing a second embodiment of the present invention.

FIG. 3 is a block diagram of a video conference system showing a third embodiment of the present invention.

FIG. 4 is a block diagram of a conventional video conference system of the present invention.

[Explanation of symbols] 1 Television conference terminal device 2
Line termination device 3 Transmission lines 4a, 4b, 4c Encoding/decoding device 5a
Audio data evaluation device 5b Image data evaluation device 5c Transmission amount selection device 6 Control devices 31, 32 Channels 41a, 41b, 41c Image encoding device 43,
43a Audio encoding device 51a Audio data measurement section 51b Image data measurement section 51c Terminal selection section 52a, 52b, 52c Judgment section 53 Request section 54 Change amount selection section 61 Transmission state holding section 62 Judgment section 63 Channel control section 64 Compression rate control Department

Claims (2)

[Claims] 1. An image encoding means that has a variable compression ratio for image signals from a television conference terminal that inputs and outputs images and sounds; and a line termination means that can secure transmission paths for different amounts of data transmission. data evaluation means for monitoring the amount of audio data or image data and evaluating the importance of the image data to be transmitted; and controlling the line termination means to secure a new transmission path based on the evaluation result by the data evaluation means. and a control means for controlling an image compression rate of the image encoding means so as to correspond to the data amount of the new transmission line. 2. Image encoding means with a variable compression rate for image signals from a television conference terminal that inputs and outputs images and audio, and line termination means that can secure transmission paths with different amounts of data transmission; transmission amount selection means capable of selecting an amount of image data to be transmitted; and control to secure a new transmission path for the line termination means based on the selection result of the transmission amount selection means; control means for controlling the image compression rate of the image encoding means so as to correspond to the amount of data of the video conference system.