JPH07288792A - Multi-spot picture transmission system - Google Patents

Abstract

PURPOSE:To provide a picture transmission system which realizes multi-spot picture transmission not using a multi-spot conference controller not bringing about complication of terminals. CONSTITUTION:In the multi-spot picture transmission system where terminals 10a to 10e at plural points are connected by a transmission line 12 like a loop, channels whose the number of is smaller than the number of these points by one are provided on the transmission line, and each of terminals 10a to 10e is provided with a display means, which synthesizes data of channels received from the transmission line into one picture to display it, and a multiplexing means which changes channels of data and puts data of its own terminal on the channel made idle by this change to transmit this data to the next terminal are provided. Picture data of terminals other than one terminal are multiplexed and transmitted to this terminal through the transmission line 12, and this terminal synthesizes these data into one picture to display it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image transmission system for transmitting image data of video conferences and video telephones to multiple points, and more particularly to a system which can be formed by a terminal having a simple structure.

[0002]

2. Description of the Related Art In a conventional video conference system or video telephone system connecting multiple points, a multipoint conference control device for controlling image data composition and data transmission is used.
As shown in, a system is configured by connecting a plurality of terminals 51 to the multipoint conference control apparatus 50 in a one-to-one relationship.

As shown in FIG. 6, each terminal 51 has an image input section 52 for inputting an image and an encoding section for encoding the input image.
53, a transmission unit 54 that transmits encoded image data to the multipoint conference control device 50, a reception unit 55 that receives image data from the multipoint conference control device 50, and a decoding unit that decodes the received image data 56 and an image display unit 57 that displays an image.

Further, as shown in FIG. 7, the multipoint conference control apparatus 50 includes receiving units 62a, 62b, 62c for receiving screen data transmitted from each terminal 51 and a decoding unit 63a for decoding image data. , 63b, 63c, a screen synthesizing unit 61 for synthesizing the images transmitted from the respective terminals, encoding units 64a, 64b, 64c for encoding the synthesized images, and the encoded image data for each terminal 51. And transmitting units 65a, 65b, 65c for transmitting to

In this system, the image input section 52 of the terminal 51 is
The image input from is encoded by the encoding unit 53 and transmitted to the multipoint conference control apparatus 50 through the transmission unit 54.

In the multipoint conference control apparatus 50, the images transmitted from each terminal 51 are decoded by the decoding units 63a, 63b, 63c, and the screen combining unit 61 combines these images into one screen. The combined image is encoded by the encoding units 64a, 64b, 64c and sent back to each terminal 51 through the transmitting units 65a, 65b, 65c.

In the terminal 51, the image data sent from the multipoint conference control apparatus 50 is received by the receiving section 55, decoded by the decoding section 56, and displayed on the image display section 57. In this way, on each terminal, the images input from the other terminals are combined and displayed on one screen.

This system requires a special device called a multipoint conference control device, and has the drawback that the capacity of this device limits the number of terminals that can participate in a video conference or the like.

In order to improve these points, a video conference system that does not require a multipoint conference control device is proposed in Japanese Patent Laid-Open No. 3-172057. In this system, each terminal is connected in a loop, and each terminal performs and processes video signal processing for replacing a predetermined portion in the screen of the image received from one terminal of the loop with its own image. Image data is being sent to the other terminal in the loop. This video signal processing replaces the portion of the scanning line corresponding to a predetermined area on the screen from the series of received image signals with the image signal of the terminal itself, and separates each screen within the screen to which each terminal is assigned. By performing such a process for the part, the images of all the terminals participating in the video conference are displayed on one screen in each terminal.

[0010]

However, in the conventional system in which each terminal is connected in a loop, since the images of each terminal are collected and displayed on the screen, each terminal performs complicated video signal processing. However, there is a problem that the circuit scale of the terminal increases.

The present invention solves these conventional problems, and without using a multipoint conference controller,
It is an object of the present invention to provide an image transmission system that realizes image transmission at multiple points without inviting complication of terminals.

[0012]

Therefore, according to the present invention, in a multipoint image transmission system in which terminals at a plurality of points are connected by a loop-shaped transmission line, the number of points on the transmission line is 1 to 1.
, A display means for synthesizing and displaying the data of each channel received from the transmission line on one screen for each terminal, and the channel of this data is transferred, and the channel vacated by this transfer Is provided with a multiplexing means for inserting the data of the own terminal and transmitting it to the next terminal.

Further, the transmission line is constituted by a bidirectional transmission line, and the number of channels obtained by subtracting 1 from the number of points is provided separately for both transmission lines.

[0014]

Therefore, the image data of each terminal other than the own terminal is multiplexed and transmitted to each terminal through the transmission path.
Each terminal can synthesize and display those data on one screen.

When a bidirectional loop-shaped transmission line is used as the transmission line, the amount of data to be transmitted on each transmission line is halved, so that image data can be transmitted quickly.

[0016]

【Example】

(First Embodiment) As shown in FIG. 1, the multipoint image transmission system of the first embodiment has terminals 10a to 10 placed at five points.
e and a loop-shaped transmission line 12 connecting them, and data of the number (4) of channels obtained by subtracting 1 from the number of points 5 is multiplexed and transmitted to the transmission line 12.

Further, as shown in FIG. 2, each of the terminals 10a to 10e separates the data of the four channels of the transmission line 12 for each channel and the separated data of each channel. Buffer units 22b to 22e for storing and each buffer unit 22
a screen synthesizing unit 23 for reading data from b to 22e and synthesizing the data into one screen data, a decoding unit 24 for decoding the synthesized image data, and a screen display unit 25 for displaying an image,
Further, an image input unit 28 for inputting an image, an encoding unit 29 for reducing and encoding the input image, and a multiplexing unit for multiplexing the encoded image data on a channel set on the transmission path 12. And a conversion unit 26.

The multiplexer 26 transfers the data of the channel coming from one side of the loop and multiplexes the data of its own terminal, transfers the data of the third channel to the fourth channel, and transfers the data of the second channel. The data is transferred to the third channel, the data of the first channel is transferred to the second channel, and the empty first
Put the terminal's data in the channel.

For example, in the terminal 10a, the data 11e of the terminal 10e is on the first channel of the transmission line 12, the data 11d of the upstream terminal 10d is on the second channel, and the data 11c of the upstream terminal 10c is on the third channel. However, the data 11b of the further upstream terminal 10b is sent to the fourth channel. Terminal
The multiplexing unit 26 of 10a moves the data 11c of the terminal 10c to the fourth channel, the data 11d of the terminal 10d to the third channel, and the data 11e of the terminal 10e to the second channel, and frees the first channel. The channel has a coding unit 29 of its own terminal.
The image data 11a that has been reduced in size and coded to have a size of 1/4 of the display screen is inserted.

The image data thus processed by the multiplexing unit 26 of the terminal 10a is transmitted to the terminal 10b. As a result, the terminal 10b that receives the image data through the transmission path 12 always receives all the other terminals 10c except the image data of its own terminal,
Image data 11c, 11d, 11e, 11a of 10d, 10e, 10a
Will receive.

The separating unit 21 of the terminal which receives the image data separates the data of the four channels of the transmission line 12 for each channel and stores them in the separate buffer units 22b to 22e. The data is read from these buffers at fixed intervals, and the data is combined on the channel where the image frame is completed at the time of reading, and on the channel where the image frame is not completed, on the same frame as the previous frame. Output to the unit 23. The screen synthesizing unit 23 synthesizes these data into one screen. The image data combined by the screen combining unit 23 is decoded by the decoding unit 24 and displayed on the image display unit 25. As a result, as shown in the image display unit 25 in FIG. 2, each terminal (10a) has four other terminals (10b, 10c, 10).
You can see the images of d and 10e) on one screen.

(Second Embodiment) As shown in FIG. 3, the multipoint image transmission system of the second embodiment has terminals 30a to 30e placed at five points and bidirectional loop-shaped transmission for connecting them. The transmission lines 32 and 33 are composed of the lines 32 and 33.
Data of two channels clockwise and two channels counterclockwise are multiplexed and transmitted.

Further, as shown in FIG. 4, each of the terminals 30a to 30e has a separating unit 41 for separating the data of a total of four channels of both transmission lines 32 and 33 for each channel, and each of the separated units. Buffer units 42b to 42e for storing data for each channel, a screen synthesizing unit 43 for reading data from the buffer units 42b to 42e and synthesizing the data into one screen data, and a decoding unit 44 for decoding the synthesized image data. , Image display section for displaying images
45 and an image input section 48 for inputting an image,
An encoding unit 49 that reduces and encodes the input image, a multiplexing unit 46 that multiplexes the encoded image data into a plurality of channels set on the transmission path 32, and the encoded image A multiplexing unit 47 that multiplexes data on a plurality of channels set on the transmission path 33 is provided.

The multiplexing units 46 and 47 are arranged in the loop 32 or 33.
The data of the channel coming in through is transferred and the data of the own terminal is multiplexed, and the multiplexing unit 46 moves the clockwise data of the first channel to the second channel, and then to the vacant first channel. Put the terminal data, and also the multiplexing unit
The 47 moves the data of the counterclockwise first channel to the second channel and puts the data of its own terminal in the vacant first channel.

For example, in the terminal 30a, the data 31e of the terminal 30e is sent to the first channel of the transmission path 32, and the data 31d of the upstream terminal 30d is sent to the second channel.
The data 31b of the terminal 30b is sent to the first channel of the transmission path 33, and the data 31c of the terminal 30c upstream thereof is sent to the second channel. The multiplexing unit 46 of the terminal 30a uses the data 31 of the terminal 30e.
While moving e to the second channel in the clockwise direction, the vacant first channel is moved to the 4th channel of the display screen by the encoding unit 49 of the own terminal.
The image data 31a, which has been reduced and encoded to have a size of one-half, is inserted, and the multiplexing unit 47 moves the data 31b of the terminal 30b to the second counterclockwise channel and is vacant. The image data 31a encoded by the encoding unit 49 of the own terminal is put in the first channel.

The image data thus processed by the multiplexing unit 46 of the terminal 30a is transmitted to the terminal 30b, and the image data processed by the multiplexing unit 47 is transmitted to the terminal 30e. as a result,
Through the transmission paths 32 and 33, each terminal always receives the image data of all other terminals except the image data of its own terminal.

The separating unit 41 of the terminal which has received the image data through the transmission lines 32 and 33 separates the data of the four channels in total for each channel, and separate buffer units 42b to 42b.
Store in e. Screen synthesis unit 43, decoding unit 44, and image display unit
At 45, the same operation as in the first embodiment is performed, and the images of the other four terminals are displayed on one screen on the image display unit 45 of each terminal.

In the system of the second embodiment, the image data amount transmitted by the transmission line of the first embodiment is divided into two parts by the bidirectional transmission line and is transmitted. Compared with this, transmission with less delay becomes possible.

[0029]

As is apparent from the above description of the embodiments, the multipoint image transmission system of the present invention does not require a multipoint conference control device, and the multipoint image data can be obtained by a simple terminal configuration. Each terminal can display a composite screen of image data of other terminals.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a configuration of a multipoint image transmission system in a first embodiment,

FIG. 2 is a block diagram showing a configuration of a terminal used in the system of the first embodiment,

FIG. 3 is a conceptual diagram showing a configuration of a multipoint image transmission system in a second embodiment,

FIG. 4 is a block diagram showing the configuration of a terminal used in the system of the second embodiment.

FIG. 5 is a conceptual diagram showing a configuration of a conventional multipoint image transmission system,

FIG. 6 is a block diagram showing a configuration of a terminal used in a conventional system,

FIG. 7 is a block diagram showing a configuration of a multipoint conference control device in a conventional system.

[Explanation of symbols]

 10a to 10e, 30a to 30e, 51 Terminals 11a to 11e, 31a to 31e Image data 12 Transmission path 21, 41 Separation section 22b to 22e, 42b to 42e Buffer section 23, 43, 61 Screen composition section 24, 44, 56, 63a to 63c Decoding unit 25, 45, 57 Image display unit 26, 46, 47 Multiplexing unit 28, 48, 52 Image input unit 29, 49, 53, 64a to 64c Encoding unit 32 Clockwise transmission line 33 Counterclockwise Circular transmission line 50 Multipoint conference control device 54, 65a to 65c Transmission unit 55, 62a to 62c Reception unit

Claims (2)

[Claims] 1. A multipoint image transmission system in which terminals at a plurality of points are connected by a loop-shaped transmission line, wherein a number of channels less one is provided on the transmission line, and each terminal is provided with: Display means for synthesizing and displaying the data of each channel received from the transmission path on one screen and the channel of the data is transferred, and the data of the own terminal is put in the channel vacated by this transfer and transmitted to the next terminal. A multipoint image transmission system comprising: 2. The transmission line is constituted by a bidirectional transmission line, and the number of the channels subtracted from the number of points is divided into both the transmission lines and provided. Multipoint image transmission system.