JP2920921B2 - Image signal transmission method and apparatus, and image conference system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a video conference system in broadband ISDN.

(Prior art) As an image conferencing system based on the conventional technology, "Electronic Information and Communication Handbook" edited by IEICE (Ohmsha)
Those described on pages 2595 to 2597 are known.

FIG. 5 is a block diagram showing the configuration of a conventional video conference system. As shown in FIG. 5, in the conventional video conferencing system, the video conference terminals including the operation terminals 500 to 503, the video cameras 520 to 523, the monitor TVs 510 to 51A3, and the multi-replexers / demultiplexers (MUX / DMUX) 530 to 533 are Is connected to the exchange 540 via a communication channel having a transmission speed for moving images. In addition, video conference trunk 5
50 is connected to the exchange 540, edits the image signal from each terminal, and distributes it again to each terminal. A control circuit 560 of the video conference trunk 550 is connected to the exchange 540, and the video conference trunk 55 is controlled by a control signal from each terminal.
Controls 0.

A case where an image conference is held using the system configuration shown in FIG. 5 will be described. The members participating in the conference control the exchange to set up one line for each of the terminals and the video conference trunk. Thereafter, a line is set between the operation terminal and the control circuit 560, and the video conference trunk 550 is controlled to perform processing such as synthesis of an image signal from the terminal,
The signal is distributed to each terminal and displayed on the terminal.

(Problems to be Solved by the Invention) According to the video conferencing system according to the prior art shown in FIG. 5, one broadband line for moving images is occupied by one line for uplink and downlink, so that other broadband information such as still image information is used. Could not send at the same time. SUMMARY OF THE INVENTION It is an object of the present invention to provide a system capable of simultaneously transmitting broadband information other than moving image information while saving line capacity.

(Means for Solving the Problem) According to the present invention, n is a natural number of 2 or more, an image signal is decomposed into an n-series 1 / n sub-sampling image signal, and the 1 / n sub-sampling image signal is An image signal transmission system characterized by transmission by a line having a band of 1 / n of the entire band of the image signal is obtained.

Further, an image signal transmission system is selected, which has a function of controlling the number of lines of the 1 / n sub-sampling image signal to be transmitted / received to a desired number.

Further, m is a natural number of 1 or more and n or less, and one or more signal conversion procedures for forming an entire screen from 1 / n sub-sampled image signals of m lines received from one or more signal sources are provided. An image signal transmission method characterized by selecting and using one of the conversion procedures is obtained.

Further, n is a natural number of 2 or more, the image signal is decomposed into an n-series 1 / n sub-sampled image signal, and each of the 1 / n sub-sampled image signals is
A transmitting unit for transmitting to a line having a bandwidth of 1n; a unit for controlling the number of lines of the 1 / n sub-sampling image signal to be transmitted / received to a desired number; A plurality of signal conversion units having one or a plurality of signal conversion units constituting the entire screen from the 1 / n sub-sampling image signals of m lines received from the terminal, and having a signal reception unit for selecting and using any of the signal conversion units An image conference system comprising: an image conference terminal; an exchange for connecting an m-line signal from the image conference terminal in a desired form under the control of the image conference terminal; and a transmission line for connecting the exchange. Is obtained.

(Operation) By decomposing the image signal into n-series 1 / n sub-sampling data and transmitting each to a line having a band of 1 / n of the entire band of the image signal, a conference is performed using the sub-sampled image. Broadband information other than conference information can be transmitted and received. Further, by transmitting and receiving the sub-sampled image, the line capacity can be saved.

(Example) The operation of the image conference system of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing a configuration of a transmission side of the line termination device shown in FIG. 1, and FIG. 3 is a configuration of a reception side of the line termination device. It is a block diagram. According to FIG. 1, the embodiment of the present invention comprises operation terminals 100 to 103 and video cameras 120 to 123.
Monitor TVs 110 to 113, operation terminals 100 to 103 at respective terminal ports, video cameras 120 to 123, and monitor TV 110
To the line termination devices 130 to 133 to which the control circuit 1 is connected.
An exchange in which a control circuit 150 is connected to a control terminal, and line ports of the line terminators 130 to 133 are connected to first to fourth terminals.
It consists of 140.

As shown in FIG. 2, the transmission side of the line terminating device 130 shown in FIG. 1 includes a control circuit 230 and a demultiplexer (DMU) in which the output of the control circuit 230 is connected to the control signal input.
X) 200, first-in first-out memories (FIFO) 210-213 whose respective inputs are connected to the first through fourth outputs of the DMUX 200, and first through fourth inputs, respectively.
It comprises a multiplexer (MUX) 220 connected to 210-213.

Further, the receiving side of the line termination device 130 shown in FIG.
As shown in FIG. 3, a demultiplexer (DMUX) 300
And a first-in first-out memory (FI-IN) in which each input is connected to the first to fourth outputs of the DMUX 300.
FO) 310 to 313 and the first to fourth inputs are FIFO 310
To 313, and a control circuit 330 whose output is connected to the control input of the MUX 320.

A case in which four people hold an image conference according to the present embodiment will be described. First, a member participating in the conference sets a line between each of the operation terminals 100 to 103 and the control circuit 150. In accordance with the configuration of the video conference, the exchange 140 is controlled via the line, and as many multiple lines as necessary for the desired transmission / reception signals are connected and set between the image terminals 120 to 123. In this case, if necessary, a branch connection such as one-to-three is also performed. Thereafter, the image signals from the video cameras 220 to 223 are multiplexed on the line by the line terminating devices 230 to 233,
Distributed to each terminal by the multiple line set by
A signal from the line is reconstructed into an image signal by the line terminating devices 230 to 233, and displayed on the terminal to perform an image conference.

Next, the operation of the line termination device will be described. On the transmitting side shown in FIG. 2, the image signal digitized by the DMUX 200 controlled by the control circuit 230 is separated into FIFOs 210 to 213 for each ABCD sampling point. MUX120 is FIFO
The signals input to 210 to 213 are multiplexed into time slots 1 to 4 of the time division multiplex transmission path, respectively.

As shown in FIG. 3, on the receiving side of the line termination device, the DMUX 300 converts the image signals multiplexed into time slots 1 to 4 of the input time-division multiplex transmission line into FIFOs 310 to 313, respectively.
To separate. Signals separated into FIFO 310-313 are control circuits
A desired image signal is reconstructed by the SEL 320 controlled by 330.

Next, what kind of image conference is performed in the present embodiment will be described. FIG. 4 shows the mode of the image conference performed in this embodiment. As an example, 1 sub-sampling image data is transmitted over one line, and a conference is held by four people.

If the terminal 1 wants to display the image signal monitor screens of the terminals 1 to 4 participating in the video conference in four parts, the terminal 1
Each of the transmitting sides of (1) to (4) transmits a 1/4 sub-sampling image signal using one line. The exchange 140 has terminals 1-4.
Are connected to the terminal 1. On the receiving side of the terminal 1, as shown in FIG.
To 313, and further, the SEL 320 is controlled by the control circuit 330, the signals are reconfigured so that the signals of the terminals 1 to 4 are divided into four and displayed, and displayed on a monitor.

When the terminal 2 wants to display the image from the terminal 1 as it is without reducing the definition, the transmitting side of the terminal 1 transmits four different 1/4 sub-sampling image signals using four lines. In exchange 140, all four lines from terminal 1 are connected to terminal 2.
Connect to On the receiving side of the terminal 2, the image signals for four lines are reconstructed into the original image signals by the SEL340 and displayed on the monitor.

If the terminal 3 wants to use only one line for the image signal in order to send other data of the image signal, the transmitting side of the terminal 3 sends out the 1/4 sub-sampled image signal using one line. The exchange 140 connects one line from the terminal 1 to the terminal 3. On the receiving side of the terminal 3, as shown in FIG. 3, the SEL 320 is controlled by the control circuit 330, the signal is reconstructed so that the signal of the terminal 1 is displayed, and the signal is displayed on the monitor. As a result, the three lines can be used for other purposes.

As described above, by using a combination of various line usage methods and terminal image display methods, it is possible to transmit and receive broadband information other than conference information while holding a conference, or to save line capacity. be able to. Also,
Since an image conference can be held only by performing simple image processing on a terminal, there is also an advantage that an image conference trunk is not required. However, it is of course possible to connect a conference trunk to the exchange 140 and make a branch connection or the like with the conference trunk as in the conventional example.

(Effects of the Invention) As described above, according to the present invention, it is possible to obtain an image conference system capable of transmitting and receiving broadband information other than image conference information while holding a conference, and of saving line capacity. .

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing the configuration of the transmission side of the line termination device shown in FIG. 1, and FIG. 3 is reception by the line termination device shown in FIG. FIG. 4 is a schematic diagram showing a connection form that can be performed in the embodiment shown in FIG. 1, and FIG. 5 is a block diagram showing a configuration of a conventional image conference system. In the figure, 101 to 103, 500 to 503 ... operation terminal, 110 to 11
3,510-513 ... Monitor TV, 120-123,520-523 ... Video camera, 130-133 ... Line terminator, 530-533 ... MU
X / DMUX, 140,340… Exchange, 150,560,230,330… Control circuit, 550… Conference trunk, 200,300… DMUX, 220…
... MUX, 320 ... SEL, 210-213, 310-313 ... FIFO respectively.

Claims (7)

(57) [Claims] An image signal is decomposed into an n-series 1 / n sub-sampling image signal, and each 1 / n sub-sampling image signal is divided into 1 / n of a band of the entire image signal. An image signal transmission method, characterized in that the image signal is transmitted through a line having a band. 2. The system according to claim 1, wherein the number of lines of the 1 / n sub-sampling image signal to be transmitted / received is controlled to a desired number.
2. The image signal transmission method according to 1. 3. The method according to claim 1, wherein m is a natural number not less than 1 and not more than n, and one or more signal conversion procedures for forming an entire screen from 1 / n sub-sampled image signals of m lines received from one or more signal sources. 3. The image signal transmission method according to claim 2, wherein one of the signal conversion procedures is selected and used. 4. An image signal is decomposed into an n-series 1 / n sub-sampling image signal, where n is a natural number of 2 or more, and each 1 / n sub-sampling image is divided into 1 / n bands of the entire image signal.
A transmission unit for transmitting to a line having a bandwidth of 1 / n, means for controlling the number of lines of 1 / n sub-sampled image signals to be transmitted / received to a desired number, one or more image conferences where m is a natural number of 1 or more and n or less. A plurality of signal conversion units having one or a plurality of signal conversion units constituting the entire screen from the 1 / n sub-sampling image signals of m lines received from the terminal, and having a signal reception unit for selecting and using any of the signal conversion units An image conference system comprising: an image conference terminal; an exchange for connecting an m-line signal from the image conference terminal in a desired form under the control of the image conference terminal; and a transmission line for connecting the exchange. . 5. An image signal is decomposed into n-series 1 / n sub-sampling image signals, where n is a natural number of 2 or more, and each of the 1 / n sub-sampling image signals is divided into 1 / n of a band of the entire image signal. An image signal transmission device comprising: means for transmitting data via a line having a band. 6. The image signal transmitting apparatus according to claim 1, further comprising means for controlling the number of lines of the 1 / n sub-sampled image signal to be transmitted / received to a desired number. 7. One or more signal conversion means, wherein m is a natural number of 1 or more and n or less, and the whole screen is formed from 1 / n sub-sampled image signals of m lines received from one or more signal sources. 7. The image signal transmission apparatus according to claim 6, wherein one of said signal conversion means is selected and used.