JPH10164542A - Picture multi-spot communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a picture multi-spot communication control system, capable of obtaining the picture of an optimal quality by a proper encoding system by improving the using efficiency of a transmission line. SOLUTION: A terminal 10 to be connected to a picture multi-spot controller (MCU) 30 transmits data of a single picture, inputted from a picture input part 11 by the encoding system of an H.261 standard, through a narrow-band transmission line 21. Then, composited picture data obtained by composting the picture data from plural terminals 10 by a picture-composing means 33 at MCU 30 is transmitted to the terminals 10 by multi-address communicating by the encoding system an MPEG 2 standard through a wide-band transmission line 22, and a picture is displayed on a picture display part 16 at the terminal 10. In order to obtain further effect, the line 21 is used at the time of transmitting single picture data from MCU 30. In addition, a respectively optimal, encoding/decoding system is used at the lines 21 and 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image multi-point control apparatus for communicating image data with a plurality of terminals located at multiple points, and synthesizes image data received from the terminals to generate synthesized image data. More particularly, the present invention relates to an image multipoint communication control system in which the terminal receives the generated composite image data and displays the image, and in particular, the use efficiency and display of a transmission path for transmitting image data and an encoder / decoder terminating the transmission path. The present invention relates to an image multipoint communication control system that can improve the quality of an image to be transmitted.

[0002]

2. Description of the Related Art Conventionally, in this kind of image multipoint communication control system, as shown in FIG. 7, a plurality of terminals 100 are connected in a star via a transmission line 200, and some image information providing devices are provided. Generally, an image multi-point control device (hereinafter abbreviated as MCU) 300 to which the 400 is directly connected is mainly configured. In this configuration, since the conventional MCU could only select an image from any one of the terminals 100 or one material image in the image information providing device 400 within the MCU, it was not possible to transmit a plurality of images at the same time, Therefore, only one image could be displayed on the terminal 100.

In a video conference system using such an image multipoint communication control system, a plurality of images,
That is, a technology capable of displaying images from a plurality of terminals or a plurality of material images, or a combination of both, on the terminal 100 is described in, for example, Japanese Patent Application Laid-Open No. 8-163529 (image multipoint communication control system).

According to the described system, the plurality of terminals 100 include an image input unit 110, an image display unit 120, an image processing unit 130, a communication unit 140, and an image control unit 15.
0, and the MCU 300 includes a communication unit 310, a screen combining unit 330, an image control unit 360, and an image broadcasting unit 370. Here, the image control unit 150 performs overall control of processing relating to an image in the terminal 100. The image control unit 360 performs overall control of processing related to images in the MCU 300.

[0005] In each of the plurality of terminals 100, the image data input from the image input unit 110 is coded by the image processing unit 130 and output via the communication means 140, and the output image data and image information providing device are provided. Each of the image data output from 400 is input to the screen combining unit 330 by the MCU 300 via the communication unit 310, and the input plurality of image data is combined by the screen combining unit 330.

[0006] The image broadcasting section 370 transmits the combined image data combined by the screen combining section 330 to a plurality of terminals 100 via the communication means 310 by broadcast control. Each terminal 1
In 00, the image processing unit 130 decodes the combined image data input from the MCU 300 via the communication unit 140 to generate a combined image, and the image display unit 120 displays the combined image as an image.

A transmission line 200 for connecting a plurality of terminals 100 and a small number of image information providing devices 400 to an MCU 300
Provides the same bandwidth for each input / output of the MCU 300, and illustrates a description example in which the combined image data is arranged and transmitted in series.

[0008] As described above, the image displayed on the image display unit 120 of the terminal 100 is obtained by changing the size of each screen by simultaneously displaying the synthesized image decoded and generated by the image processing unit 130 while dividing the screen. And a part of the composite image can be selected. As a result, even for the terminal 100 that can simultaneously display only one image, the object of being able to simultaneously provide a plurality of images by the service of the MCU 300 is achieved.

[0009]

The above-mentioned conventional image multipoint communication control system has the following problems.

The first problem is that the transmission lines connected to the terminals by the image multipoint control device usually belong to the same network and have the same transmission band (transmission capacity / transmission speed). The use efficiency of the transmission path is deteriorated, the control is complicated, or the image quality is deteriorated.

The reason is that, in order to display partial data on the screen from the composite image data input by the terminal, the single image data received from the terminal by the image multipoint controller and the composite image transmitted by the image multipoint controller to the terminal are displayed. An unbalanced transmission path band is used with image data. For example, if an optimal transmission path is secured for data transmission such as multi-screen composite image data, the image multipoint control device receives a single A considerable amount of unused part occurs in the image data,
On the other hand, when an optimal transmission path is used for single image data, control for simultaneously using a plurality of transmission paths, or data thinning out if only one transmission path is used, is required.

The second problem is that the coding method used for the terminal by the image multipoint control device is usually the same, so that the use efficiency of the encoder / decoder deteriorates and the image Excessive quality or poor quality occurs.

The reason is that the amount of information required for transmission of the composite image data sent to the terminal by the image multipoint control device to the single image data received by the image multipoint control device from the terminal is plural times as in the above reason. Therefore, when the most suitable coding method is used for the transmission of the composite image data, the quality is excessive on the other hand, and when the most suitable coding method is used for the transmission of the single image data, the quality deteriorates. Is inevitable.

An object of the present invention is to solve the above problems,
An object of the present invention is to provide an image multipoint communication control system capable of improving the efficiency of use of a transmission path and obtaining an optimal high-quality image by an appropriate encoding method.

[0015]

An image multipoint communication control system according to the present invention comprises an image multipoint control device for communicating image data with a plurality of terminals located at multiple points. In the image multipoint communication control system in which the terminal receives and displays the synthesized image data generated by generating the synthesized image data by synthesizing the image data, the image multipoint control device includes a transmission line for inputting image data from the terminal. Means for selecting a transmission path of a transmission band different from the transmission band (transmission capacity / transmission speed) and transmitting the synthesized image data to each connected terminal.

More specifically, when the image data to be transmitted to the terminal is a single image, the image multi-point control device has a transmission band having the same transmission band as a transmission line for inputting image data from the terminal. Switching means for selecting and using a transmission path having a transmission band different from the transmission path for inputting image data from the terminal only when the image data to be transmitted to the terminal is a composite image, And coded transmitters respectively corresponding to transmission paths having different transmission bands. Further, the terminal includes a receiver decoder corresponding to each of the transmission paths having different transmission bands, and a switch for selecting and displaying the image data input via the transmission path and the receiver decoder. ing.

That is, a transmission path having an optimum transmission band corresponding to a transmission amount of image data to be transmitted, for example, single image data and composite image data, is selected.
In addition, an optimal coding method can be applied.

[0018]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a functional block diagram showing an embodiment of the present invention. In the image multipoint communication control system shown in FIG. 1, a plurality of terminals 10 communicate with each other via a narrowband transmission line 21 and a wideband transmission line 22.
It is assumed that the image information providing device 40 is connected to the MCU 30.

Here, the point different from the conventional one is that the terminal 10 and the MCU 30 have different narrow band transmission lines 2 having different transmission bands.
1 and the broadband transmission line 22.

The terminal 10 includes an image input unit 11, a narrow-band coded transmitter 12, a narrow-band receiver decoder 13, a wide-band receiver decoder 14, a switch 15, an image display unit 16, and a terminal control unit 17. The functions that are not directly related to this function are omitted from the description and illustration.

The MCU 30 includes a narrow-band receiver decoder 31,
It is assumed that the apparatus includes a screen selecting unit 32, a screen synthesizing unit 33, a narrowband coded transmitter 34, a wideband coded transmitter 35, and an MCU control unit 36. Functions not directly related to this function are described and illustrated. It shall be omitted.

The image input unit 11 captures an image from a television camera or the like, converts the image into single image data based on electric signals, and outputs the single image data.

The narrow-band coded transmitter 12 is connected to the narrow-band transmission line 21, inputs single image data output from the image input unit 11, and performs single-image coding by predetermined digital coding. It is assumed that the data is converted into data and output to the MCU 30 of the connection destination via the narrow band transmission path 21.

The narrow-band receiver decoder 13 is connected to the narrow-band transmission line 21, and is connected to the MCU via the narrow-band transmission line 21.
It is assumed that the coded single image data is input from 30, converted into single image data by predetermined decoding, and transmitted to the switch 15.

The broadband receiver decoder 14 is connected to the broadband transmission line 22, and is connected to the MCU via the wideband transmission line 22.
It is assumed that the composite image coded data is input from 30, converted into composite image data by predetermined decoding, and transmitted to the switch 15.

The switch 15 changes the image display data from the single image data input from the narrowband receiver decoder 13 and the composite image data input from the wideband receiver decoder 14 in accordance with an operation instruction on the terminal 10. It is assumed that the selected image is output to the switching image display unit 16.

The image display unit 16 displays input image data such as a monitor display on a screen.

It is assumed that the terminal control section 17 performs overall control of processing relating to the image of the terminal 10.

The narrow-band receiver decoder 31 is connected to the narrow-band transmission line 21, and the terminal 1 is connected via the narrow-band transmission line 21.
It is assumed that coded single image data is input from 0, converted into single image data by predetermined decoding, and output to the screen selecting means 32.

The screen selecting means 32 inputs single image data from the plurality of narrowband receiver decoders 31 and the image information providing device 40, and selects the designated terminal 10 from the plurality of input single image data. Selects and outputs at least one single image data designated by the user to the screen combining means 33, and selects and switches the image data received from the screen combining means 33 based on the data amount of the received image data. It is to be output to the band coded transmitter 34 or the wide band coded transmitter 35.

The screen synthesizing means 33 synthesizes a plurality of input single image data in a predetermined format to generate synthesized image data, and outputs the single image data to the screen selecting means 32 as it is. I do.

The narrow-band coded transmitter 34 is connected to the narrow-band transmission line 21, receives single image data output from the screen selecting means 32, and performs predetermined coding to perform single-image coded data. , And broadcast to all the connected terminals 10 via the narrowband transmission line 21.

The wide-band coded transmitter 35 is connected to the wide-band transmission path 22, receives the composite image data output from the screen selection means 32, converts the composite image data into predetermined coded data by a predetermined coding, The broadcast is output to all the connected terminals 10 via the broadband transmission path 22.

The MCU control unit 36 performs an overall process relating to the image of the MCU 30.

The narrow-band transmission line 21 has a transmission band suitable for transmitting single-image encoded data output from the image input unit 11 and encoded by the narrow-band encoding transmitter 12. Has a transmission band suitable for transmission of encoded image data of a predetermined size synthesized by the screen synthesis means 33 of the MCU 30.

FIG. 2 is an explanatory diagram showing the connection of a plurality of devices in FIG. The screen selecting means 32 of the MCU 30 includes the outputs of the n image information providing devices 40-1 to 40-n and the m terminals 10-1 to 10 through the narrowband transmission line 21.
-m output is connected. The two outputs of the switching means 34 of the MCU 30 are respectively connected to the m terminals 10-1 connected via the narrowband transmission line 21 or the wideband transmission line 22.
Broadcast to 10-m.

Next, the main operation procedure of the terminal 10 will be described with reference to FIGS.

For simplicity, the terminals 10-1 to 10-m participating in the television conference are connected to the MCU 30 via the transmission line 2.
The terminal 10-1 is the chairman, and whether the image displayed on the screen from the terminal 10-1 is a single image or a composite image and which single image is to be synthesized in the case of the composite image. Shall be specified.

First, the terminals 10-1 to 10-m capture an image by using the image input unit 11 (procedure S1), encode image data, and transmit the narrowband transmission line 21 from the narrowband encoding transmitter 12 to the narrowband transmission line 21. The data is transmitted to the MCU 30 via the CPU 30 (procedure S2).

The terminals 10-1 to 10-m accept the designation of the image to be used in the conference from the chair terminal 10-1 (step S3).
When a synthesized image is used (YES in step S4), the wideband receiver decoder 14 is selected by the input of the switch 15 (step S5).

The broadband receiver decoders 14 of the terminals 10-1 to 10-m receive the composite image coded data from the MCU 30 via the wideband transmission path 22 by broadcasting (step S6). The composite image encoded data is decoded (step S7), sent to the image display unit 16 via the switch 15 and displayed on the image display unit 16 (step S8), and the procedure is terminated.

If the above step S4 is "NO" and the image is a single image, each of the terminals 10-1 to 10-m selects the narrow band receiver decoder 13 by the input of the switch 15 (step S11),
When an encoded image is received (procedure S12), the received single-image encoded data is decoded (procedure S13) and transmitted to the image display unit 16 via the switch 15 to be transmitted to the image display unit 16
To step S8 for displaying an image.

Next, referring to FIG. 4 together with FIGS.
The main operation procedure of U30 will be described.

First, the MCU 30 is connected to the terminals 10-1 to 10-m and the image information devices 40-1 to 40-n as described above and shown in FIG. Shall be

In the MCU 30, the single-band image data of each of the terminals 10-1 to 10-m is received by the narrow-band receiver decoder 31 corresponding to each of the terminals 10-1 to 10-m via the narrow-band transmission line 21. And decrypts the data (procedure S21). The MCU 30 checks the provision of the material image from the image information providing device 40 (step S2).
2) If an image is provided (YES in step S23), the material image data is input to the screen selecting means 32 (step S24).

In the MCU 30, the screen selection means 32 receives the designation from the chair terminal 10-1 (step S25), and selects an image to be used.

When the composite image is designated (YES in step S26), the screen selecting means 32 selects the image to be composed designated from the chair terminal 10-1 among the input single image data and material image data. Select the data (step S2
7), the image data is sent to the screen synthesizing unit 33, and the screen synthesizing unit 33 generates synthesized image data (step S28), and the screen selecting unit 32 selects the wideband coded transmitter 35 (step S29).

The wideband coding transmitter 35 transmits the synthesized image data generated and output by the screen synthesizing means 33 and received through the screen selecting means 32 to the terminal 1 via the wideband transmission path 22.
0-1 to 10-m by broadcast (step S
30), end the procedure.

If a single image is designated in step S26, the screen selecting means 32 transmits the designated single image data and material image data specified by the chair terminal 10-1. Image data to be selected is selected (procedure S31), sent to the screen synthesizing means 33, and the narrow-band coded transmitter 34 is selected (procedure S32).

The narrow-band coded transmitter 34 transmits the single image data or the material image data output from the screen synthesizing unit 33 and received through the screen selecting unit 32 through the narrow-band transmission line 21 according to the above-described procedure S30. The broadcast is sent to each of 10-1 to 10-m by broadcast, and the procedure ends.

[0052]

Next, a first embodiment of the embodiment shown in FIGS. 1 and 2 will be described with reference to FIG. Therefore, the configuration of the device shown in FIG.
Is the same as the configuration shown and described above.

In the illustrated image multipoint communication control system, three terminals 50-1 to 50-3 and two video servers 60-1 and 60-2, which are image information providing devices, are connected to a single MCU.
70 to form a conference network.

The narrow-band transmission line is an ISDN (Integrated Services Digital Network) line 23, and the encoding system of the single image data to be transmitted is a videophone / telephone of ITU-T (International Telecommunication Union / Telecommunication Standardization Division). Video coding standard for videoconferencing H.264. 261 standard.

On the other hand, the broadband transmission path is a high-speed digital line 2
4, and the encoding method of the transmitted composite image data is
MPEG which is a standard organization of a color moving picture coding system, which is a general-purpose coding standard using common text of ITU-T and ISO / IEC JTC1 (International Organization for Standardization / International Electrotechnical Commission / Joint Technical Committee 1). (MovingPi
(Cture Experts Group).

In each of the terminals 50-1 to 50-3, a video camera 51 serving as an image input unit, a switch 55, and a television monitor 56 serving as an image display unit are illustrated, and a terminal control unit (not illustrated) includes a personal computer. Is used. It is assumed that each of the terminals 50-1 to 50-3 sends out the single image data A, B, C.

Also, each of the terminals 50-1 to 50-3 and the MC
The connection with U70 is the same as in FIG. 2, and it is assumed that the connection is via the ISDN line 23 of the narrow band transmission line and the high-speed digital line 24 of the wide band transmission line.

It is assumed that the chair of the conference is the terminal 50-1, and the terminal control unit and MCU of each of the terminals 50-1 to 50-3.
It is assumed that the personal computer serving as the MCU control unit 70 receives a designation from the chair terminal 50-1 and performs predetermined operation processing. Further, in order to specify the output of the MCU 70, a single image data is selected and the ISDN line 23 of the narrow band transmission line is selected.
And a "single image mode" in which the composite image data is selected and the high-speed digital line 24 of the broadband transmission line is used.

It is assumed that each of the video servers 60-1 and 60-2 sends single material image data X and Y to the MCU 70.

In the MCU 70, a matrix switcher 72 serving as a screen selecting means and a 6-input 6-output signal switch and a 4-screen splitting unit 73 serving as a screen synthesizing means are shown, and a personal computer is used for an MCU control unit (not shown). It is assumed that

The matrix switcher 72 is connected to the terminal 50-1.
-3 and video data A, B, C, X, and Y output from each of the video servers 60-1 and 60-2, and the four image data designated and selected from the chair terminal 50-1 are input. On the other hand, it is assumed that the output from the four-screen splitting unit 73 is input, and one of the narrowband transmission path 23 and the wideband transmission path 24 is selected and output.

The four-screen division unit 73 combines the four outputs of the matrix switcher 72 into a four-divided screen and outputs it to the matrix switcher 72.

Next, the operation in FIG. 5 will be described.

Each of the terminals 50-1 to 50-3 participating in the conference uses the video camera 51 to photograph the state of the conference attendees, and captures the single image data A, B, and C, respectively. The fetched single image data A, B, and C are H.264. H.261, and is transmitted to the image multipoint control transmission device 70 via the ISDN line 23 and decoded.

Each of the video servers 60-1 and 60-2
For example, each of the material image data X and Y specified by the request from each of the terminals 50-1 to 50-3 is stored in the MCU.
70.

In the MCU 70, the matrix switcher 7
2 are single image data A, B, C and material image data X,
Y is input, and the single image data A and B and the material image data X and Y are selected by designating the "composite image mode" of the chair terminal 50-1 and output to the four-screen division unit 73. I do.

The four-screen division unit 73 divides one screen into four parts vertically and horizontally, and combines the images in which the single image data A and B are arranged on the upper left and right and the material image data X and Y are arranged on the lower left and right respectively. It is generated and output as image data and sent to the matrix switcher 72.

The combined image data A, B, X, and Y that need to be transmitted on the broadband side by designating the “synthesized image mode” of the receiving chair terminal 50-1 from the four-screen division unit 73 are converted into high-speed digital data by the matrix switcher 72. After being switched to the line 24 and encoded according to the MPEG2 standard, it is output to all the terminals 50-1 to 50-3 via the high-speed digital line 24 by broadcast communication.

In each of the terminals 50-1 to 50-3, the designation of the composite image display is obtained by designating the "composite image mode" of the chair terminal 50-1. And the single image data A,
B is the upper left and right, the material image data X and Y are the lower left and right,
The images arranged for each are displayed on the screen of the television monitor 56.

On the other hand, in the MCU 70 by the "single image mode" designation of the chair terminal 50-1, the matrix switcher 72 of the MCU 70 selects one of the five inputs of the single image data A, B, C and the material image data X, Y. And outputs it to the four-screen splitting unit 73.

The four-screen division unit 73 sends the received single image data to the matrix switcher 72.

The single image data that needs to be transmitted on the narrow band side by the designation of the “single image mode” of the chairperson terminal 50-1 from the four screen division unit 73 is switched to the ISDN line 23 side by the matrix switcher 72. H. 2
After being coded according to the I.61 standard, I
The data is output to all the terminals 50-1 to 50-3 via the SDN line 23.

In each of the terminals 50-1 to 50-3, the designation of the composite image display is obtained by designating the "single image mode" of the chair terminal 50-1.
An image obtained by capturing the line on the line 23 side and decoding the input single image data is displayed on the screen of the television monitor 56.

Next, a second example of the embodiment shown in FIGS. 1 and 2 will be described with reference to FIG.

In the second embodiment, only the composite image specified by the chair is provided to all terminals 80-1 to 80-3, and the system is simplified by omitting the provision of a single image. .
With this configuration alone, the use efficiency of the transmission path can be improved, and an optimal high-quality image can be obtained by an appropriate encoding method.

The configuration of the apparatus shown in FIG. 6 is the same as the configuration described with reference to FIG. 1 or FIG. 5, except that the terminals 80-1 to 80-3 do not have a switching unit, and , MC
In U90, the five-input / four-output signal switch 92 as the screen selecting means is switched to the four-screen dividing unit 9 as the screen synthesizing means.
3 is lacking the portion for selecting the output.

In each of the terminals 80-1 to 80-3, a video camera 81 as an image input unit and a television monitor 86 as an image display unit are shown, and a personal computer is used for a terminal control unit (not shown). I have. Each of the terminals 80-1 to 80-3 has a single image data A, B, C
Each shall be transmitted.

Further, each of the terminals 80-1 to 80-3 and the MC
The connection with U90 is the same as that in FIG. 2, and it is assumed that the connection is via the ISDN line 23 of the narrow band transmission line and the high speed digital line 24 of the wide band transmission line.

The chair of the conference is the terminal 80-1, and the terminal control units of the terminals 80-1 to 80-3 and the M
It is assumed that the personal computer 94 serving as the CU control unit performs a predetermined operation process in response to the designation from the chair terminal 80-1.

It is assumed that each of the video servers 60-1 and 60-2 sends single material image data X and Y to the MCU 90.

The MCU 90 includes a five-input / four-output signal switch 92 as a screen selection means, a four-screen division unit 93 as a screen synthesis means, and a personal computer 94 as an MCU control unit.

The 5-input / 4-output signal switch 92 is connected to the terminal 80
-1 to 80-3 and image data A, B, C, X, and Y output from the video servers 60-1 and 60-2, respectively, and the four images designated and selected from the chair terminal 80-1 Output data.

The four-screen division unit 93 combines the four outputs of the five-input / four-output signal switch 92 into four-divided screens and directly encodes them via the wideband encoding transmitter (see FIG. 1). Thereafter, each terminal 8 is connected via the high-speed digital line 24.
0-1 to 80-3 are output by broadcast communication.

Next, the operation in FIG. 5 will be described.

Each of the terminals 80-1 to 80-3 participating in the conference uses the video camera 81 to photograph the state of the conference attendees and captures the single image data A, B, and C, respectively. The fetched single image data A, B, and C are H.264. H.261, and is transmitted to the image multipoint control transmission device 90 via the ISDN line 23 and decoded.

The video servers 60-1 and 60-2 respectively
For example, each of the material image data X and Y specified by the request from each of the terminals 80-1 to 80-3 is stored in the MCU.
90.

In the MCU 90, the single image data A, B,
5 inputs 4 for inputting C and five pieces of material image data X and Y, and selecting and outputting four pieces of single image data B and C and material image data X and Y according to designation of the chair terminal 80-1. The output signal switch 92 outputs the single image data B and C and the material image data X and Y to the four-screen division unit 93.

The four-screen division unit 93 divides one screen into four parts vertically and horizontally, and combines single image data B and C on the upper left and right and material image data X and Y on the lower left and right. After being generated and output as image data B, C, X, and Y, and directly coded according to the MPEG2 standard via a wideband coded transmitter (see FIG. 1), each terminal 80 is coded via a high-speed digital line 24. -1 to 80-3 are output by broadcast communication.

In each of the terminals 80-1 to 80-3, the line on the high-speed digital line 24 side is fetched, the synthesized image data to be input is decoded, and the single image data B and C are converted to the upper left and right and the material image data X. , Y are displayed on the screen of the television monitor 86 on the left and right sides, respectively.

In the above description, two bands are set for the transmission line. However, the use efficiency of the transmission line can be further improved by setting a plurality of appropriate bands. This means that a high quality image can be obtained even if the terminal freely selects only single image data or only the material image data portion from the composite image data received from the image multipoint control unit (MCU). . In this case, the number of interfaces with the transmission path increases, but if the terminal and the image multi-point control device are dedicated to the conference, the functional effect is significantly increased with respect to the cost.

[0091]

As described above, according to the present invention, the following effects can be obtained.

The first effect is that the transmission path can be used effectively.

The reason is that, based on the amount of information to be transmitted, a high-speed transmission path having a wide bandwidth is selected for synthetic image data having a large amount of information, while a single image data having a small amount of information is selected. This is because the transmission capacity of the transmission line is not likely to be excessive or deficient by appropriate selection and use such as selecting and using a low-speed transmission line with a narrow bandwidth.

The second effect is that the quality of the image displayed on the terminal is good. In particular, it is possible to avoid image quality deterioration even by partial extraction of the received composite image data.

The reason is that in transmitting and receiving data between each terminal and the image multi-point control device, different types of transmission paths can be selectively used for transmission and reception, so that the same encoding / decoding method is used for transmission and reception. This is because it is not necessary to adopt the above, and it is possible to select an optimal encoding / decoding method according to the amount of information transmitted on each transmission path to be used.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram showing connection of a plurality of devices in FIG.

FIG. 3 is a flowchart showing one mode of a main operation procedure of a terminal in the present invention.

FIG. 4 is a flowchart showing one embodiment of a main operation procedure of the image multi-point control device according to the present invention.

FIG. 5 is a functional block diagram showing a first embodiment of the present invention.

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

FIG. 7 is a functional block diagram showing an example of the related art.

[Explanation of symbols]

 10, 50-1 to 50-3, 80-1 to 80-3 Terminal 11 Image input unit 12, 34 Narrow band coding transmitter 13, 31 Narrow band receiver decoder 14 Wide band receiver decoder 15, 55 Switching Device 16 image display unit 17 terminal control unit 21 narrow band transmission line 22 wide band transmission line 23 ISDN (Integrated Services Digital Network) line 24 high speed digital line 30, 70, 90 image multipoint control unit (MCU) 32 screen selection means 33 screen Synthesizing means 35 Broadband coding transmitter 36 MCU control unit 51, 81 Video camera 56, 86 TV monitor 60-1, 60-2 Video server 72 Matrix switcher 73, 93 4 screen division unit 9 5 input 4 output signal switch

Claims (5)

[Claims] An image multi-point control device that communicates interim image data with a plurality of terminals located at multiple points generates composite image data by synthesizing image data received from the terminals and generates the composite image. In the image multipoint communication control system in which the terminal receives data and displays the image, the image multipoint control device includes a transmission band different from a transmission band (transmission capacity or transmission speed) of a transmission line for inputting image data from the terminal. An image multipoint communication control system, comprising means for selecting the transmission path of (1) and transmitting the combined image data to each of the connected terminals. 2. A transmission line according to claim 1, wherein, when the image data to be transmitted to the terminal is a single image, the transmission line having the same transmission band as the transmission line for inputting the image data from the terminal. Switching means for selecting and using a transmission path having a transmission band different from the transmission path for inputting image data from the terminal only when the image data to be transmitted to the terminal is a composite image. An image multipoint communication control system characterized by the following. 3. The image multipoint communication control system according to claim 2, wherein the image multipoint control device includes an encoding transmitter corresponding to each of transmission lines having different transmission bands. 4. The terminal according to claim 1, wherein the terminal selects a receiver decoder corresponding to each transmission path having a different transmission band, and selects image data input via the transmission path and the receiver decoder. An image multipoint communication control system, comprising: a switch for displaying an image. 5. The image multipoint communication control system according to claim 4, wherein the switch of the terminal has a function of selecting a part of the synthesized image input from the wideband transmission path and displaying the selected image.