JPH0263288A - Picture display system for multi-point television conference - Google Patents

Abstract

PURPOSE:To display picture information from all terminal equipments simultaneously by displaying only the picture information from a terminal equipment selected by a center node as moving picture information and displaying other picture information in terms of a still picture. CONSTITUTION:A center node 100 applies connection changeover control of a moving picture according to a command from a control terminal equipment 101, moving picture information is subject to reduction processing in terminal equipments 111-114, coding processing is applied and the moving picture information received from the center node 100 is decoded and written in an area of a frame memory 144 designated corresponding to each terminal equipment in advance and the output of the frame memory 144 is inputted to a digital/analog conversion means and an output of a D/A conversion means 145 is inputted to a picture monitor means 146. Thus, the picture information from the terminal equipments 111-114 is displayed on the same pattern simultaneously and the picture information from the terminal equipment selected in the center node 100 in the picture display system is displayed as a moving picture and the picture information from the terminal equipment not selected is stored to the frame memory 144 and displayed as a still picture. Thus, the moving picture from each terminal equipment is displayed simultaneously.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an image display method for multipoint video conferencing.

[Conventional technology]

A first example of a conventional image display method for multipoint video conferencing will be described with reference to FIG.

In FIG. 4, four conference terminals A, B, C, and D are connected to the center node 200, and for example, terminal A transmitter 2
01, the input analog video (the analog signal is converted into digital information in the digital converter (hereinafter referred to as A/D) 211, and then the encoder (hereinafter referred to as encoded)) 212 converts the data into data. The data is subjected to volume compression processing and transmission frame processing, and then transmitted to the center node 200. Similarly, for terminals B, C, and D, the transmitter 2 of each terminal
02, 203, and 204, the moving image information is transmitted to the center node 200. The center node 200 selects the terminal A according to the video selection signal input from the control terminal 240.
, B, C, D transmitting units 201.202, 203.204
jH interpretation of the only moving image from the moving image information from. Video selection is typically controlled by the conference chair. FIG. 4 shows that the moving image from terminal B has been selected. The moving image of the selected terminal B is then broadcast to all terminals. In FIG. 4, terminal B receives its own image, but it is conceivable that it does not transmit it to terminal B at this time.

Such broadcast video signals are received and processed by each terminal as follows.

FIG. 4 shows the reception process in the terminal A receiving unit 221. First, the moving image information of the terminal B received from the center node 200 is processed by an image decoding unit (hereinafter referred to as decoding).
At 231, the image encoding process is reversely processed, and then the image is stored in the frame memory 23 in order to be displayed on the monitor 234.
recorded in 2. The output is converted from a digital signal to an analog signal by a digital/analog converter (hereinafter referred to as D, , 'A) 221 and displayed on a monitor 234. Similarly, one video image from terminal B is displayed on all other terminals. Monitor 23 at this time
A display example of No. 4 is shown in FIG. 6(a). FIG. 6(a) is an example in which a moving image f from terminal B is displayed on the monitor 234. Similarly, when the same image from terminal C is selected by the moving image selection signal, the same image from terminal B disappears from the monitor 234 and a new image from terminal C is displayed as shown in FIG. 6(b). Video images from the terminal will be displayed on the monitor of each terminal.

A second example of a conventional image display method for multipoint video conferencing will be described with reference to FIG.

In FIG. 5, four conference terminals A, B, and C1D are connected to the center node 250.

It is assumed that the transmitting sections 261 to 264 and the receiving sections 271 to 274 of each terminal A, B, C, and D have the same configuration as in FIG. 4. The moving image information transmitted from the transmitting units 261 to 264 of each terminal is decoded by decoding units 251, 252, 253, and 254 at the center node 250, respectively, and then by an image reduction unit (hereinafter referred to as reduction) 255. ,256,2
The reduction process is performed by 57°258. This is because the number of terminals is 4, so the screen size is -
Suppose that This means that the outputs from the reduction units 255 to 258 are input to the buffer memory 259, the four outputs are combined into one screen, and the encoding process is performed in the encoding unit A.
, B, C, and D. The receiving units 271 to 274 of each terminal A, B, C, and D perform reception processing in the same manner as in the case of FIG. 4, and display it on the monitor. An example of the monitor display at this time is shown in FIG. 6(C). Unlike the method shown in FIG. 4, the method shown in FIG. 5 simultaneously displays reduced moving images from each terminal on one monitor. Figure 6 (C
), the monitor screen is divided into four parts, and one video image from each terminal indicated by symbols A, B, C, and D is displayed.

[Problem to be solved by the invention]

The image display method of the conventional multipoint video conference described above is a so-called switching method in the image display method shown in FIG.
The moving image from the only terminal selected by the moving image selection signal from the control terminal is displayed.7 With this image display method, the center node can perform simple switching control, but the conference is held at multiple points. Nevertheless, it has the disadvantage that only the same image from one terminal can be displayed at the same time, and because of this, it is not possible to display moving images from each participating terminal at the same time, which significantly reduces the sense of realism. be.

Furthermore, in the image display method shown in Fig. 5, the same image from each terminal is displayed simultaneously on one monitor in order to solve the problem of the switching method shown in Fig. 4. Since the center node performs decoding processing and encoding processing for each end that is not supported, there are disadvantages in that the processing delay is twice that of FIG. 4 and the equipment cost increases.

[Means to solve the problem]

The image display method for a multipoint video conference according to the present invention is a multipoint video conference in which a control terminal and a plurality of terminals are connected to a center node, and image information from all partner terminals is displayed simultaneously between the terminals. In the image display method, each of the plurality of terminals includes an A/D conversion means for A/D converting input image information, and output image information of the A/D conversion means by a first control signal from the center node. An image reduction means that performs image reduction processing, an image encoding means that encodes the reduced image information of the image reduction means and transmits it to the center node, and broadcast image information broadcast from the center node. an image decoding means for decoding the broadcast image information; a frame memory for storing the broadcast image information; an image monitor means for D/A converting and displaying the image information from the frame memory; frame memory writing area switching means for writing output information from the image decoding means into an area of the frame memory designated in advance corresponding to each of the terminals according to a control signal; Broadcasting means for selecting encoded image reduction information from the plurality of terminals according to an image selection control signal from the control terminal and broadcasting the selected encoding image reduction information to the plurality of terminals; , a control means for transmitting the first control signal and the second control signal to the plurality of terminals in response to a display image control signal from the control terminal.

[For production]

In the image display system for multipoint video conferences of the present invention, the center node performs video connection switching control according to instructions from the control terminal, and each terminal performs encoding processing after the video information is reduced. After being decoded, the video information received from the center node is written to the area of the frame memory designated in advance as unsupported at each end, and the output of the frame memory is input to the digital/analog conversion means. The output of the digital/analog conversion means is input to the image monitoring means. This results in
The image display method for multipoint video conferencing of the present invention can simultaneously display image information from each terminal on the same screen, and among such image display methods, the image information from the terminal selected by the center node can be displayed as a moving image. For image information from terminals that are not selected, image information stored in the frame memory is displayed as a still image.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a functional block diagram of an image display system for a multipoint video conference showing an embodiment of the present invention.

In FIG. 1, this embodiment includes a control terminal 101 that controls a display screen, and terminals A and B for video conferences.

C, D, and a center node 100, terminal A has a transmitter 111 and a receiver 121, terminal B has a transmitter 112 and a receiver 122, and terminal C has a transmitter 112 and a receiver 122. 113 and a receiving section 123, and the terminal has a transmitting section 114.
The center node 100 has input ports 150, 151, 152, 153 and an output port 15.
4 and a control section that controls the switching section using a control signal from the control terminal 101.

The transmitter 111 of the terminal A also has an A/D 131 that performs A/D conversion of image input, a reduction 142 that performs reduction processing on the output information of the A/D 131 according to a control signal from the center node 100, and The receiving unit 121 of terminal A includes a decoding unit 141 that decodes the received information, and a decoding unit 132 that encodes the output information and transmits the encoded information to the center node 100. The center node 10 sends the received signal to the frame memory 144.
A frame memory write area switching unit 143 that writes to each area according to a control signal from frame memory 144, and a D/A 145 that performs D/A conversion to display a signal from the frame memory 144 on a monitor 146. ing.

Note that the transmitting units 112, 113, and 114 of terminals B, C, and D have the same circuit configuration as the transmitting unit 111 of terminal A;
, C, and D have the same circuit configuration as the receiving section 121 of terminal A, and are not shown in the drawings.

Next, a screen display operation when a video conference is held between four conference terminals A, B, C, and D connected to the center node 100 using the method shown in FIG. 1 will be described.

Each terminal A, B, C, D has a transmitter 111, 112゜113
．． 114 and receiving sections 121, 122, 123.124
have. Each terminal A, B, C.

The configuration of the transmitting sections 11, 112, 113, 114 of D is -
As an example, as shown in the transmitter 111 of terminal A, the A/D
131, reduction 142, and encoding 132.

The moving image information input from a camera etc. is A/D1.3.
1, the analog signal is converted into a digital signal, and then reduction processing is performed in reduction 142.

FIG. 2 is a functional block representing an example of the image reduction means of the terminal of this embodiment. In Figure 2 A/D 300
The output video information is input to a memory 302 having a capacity of 4 nbits for one monitor screen. Next, the video information for one monitor screen is reduced. In the example shown in FIG. 1, the number of terminals is four, so the center node
Reduce the screen size to - by controlling from 0. (As a result, one screen can be divided into four parts and an image can be displayed on each divided screen according to the terminal, as shown in the reception processing described later.) This reduction processing can be performed, for example, when the output from the A/D converter 303 is n.
The data is written to a memory 304 having a capacity of 1 bit. Next, the image information written to the memory 304 is encoded 13
After being subjected to information compression processing and transmission frame processing in step 2,
The video information input to the nine other terminals B, C, and D that is transmitted to the switching unit of the center node 100 is similarly processed and transmitted to the switching unit of the center node 100. The center node 100 selects one of the moving image information transmitted from each terminal.

This moving image selection information is input from the control terminal 101 and transmitted to the control section of the center node 100.

Usually, at least one control terminal 101 is installed in the entire system. In the video switching control method by the chairman, only one chairman is selected from terminals A, B, C, and D, and only the video selection information from the chairman is valid. FIG. 1 shows a case where a moving image from terminal B is selected by a moving image selection signal from control terminal 101. In FIG. That is, the control unit of the center node 100 connects the input board 151 of the switching unit of the center node 100 to the output port 154 according to the selection information, thereby broadcasting the moving image information from terminal B to all terminals. In FIG. 1, terminal B receives its own image, but at this time, it is conceivable that it will not transmit it at the time of broadcasting on the terminal day.

The video signals broadcast in this way are sent to each terminal AB, C,
D receives the data as follows.

Although FIG. 1 shows the reception process at the terminal, the moving image information of terminal B received from the center node is decoded 141 and subjected to the reverse process of the image encoding process.

FIG. 3 is a functional block diagram showing an example of the frame memory write control section of the terminal in this embodiment.

Next, the state of frame memory write control will be explained using FIG.

In FIG. 3, the decoder 400 outputs moving image information in units of nbit information, which is the minus of the information amount for one monitor screen. Frame memory write area switching means 40
1, a write start address of the frame memory 402 for writing the decoded n-bit video information into the frame memory 402 having a capacity of 4 nbits for one monitor screen is specified under the control of the center node. The areas of the frame memory 402 have a one-to-one correspondence with the display positions on the monitor screen, and in the example shown in FIG.
2 is in area m1, the n-bit area starting from address a2 is in area m2 on the monitor 402, the n-bit area starting from address a3 is in area m3 on the monitor 402,
The nbit area starting from address a4 is the monitor 402
The upper degrees are respectively associated with the area m4. The image display position on the monitor of each terminal A, B, C, and D is determined in advance.

It is assigned to D. In the example in Figure 3, address a
Video information from terminal A is written in the nbit area starting from address 1, video information from terminal B is written in the nbit area starting from address a2, and video information from terminal C is written in the nbit area starting from address a3. An example is shown in which moving image information is written, and moving image information from the terminal is written in the n-bit area starting from address a4. In the example shown in FIG. 1, moving image information from terminal B is sent to terminal A.

Broadcasting is broadcast to B, C, and D, but for example, n starting from address a2, which is a dedicated area for receiving video information on terminal A.
Periodically write to the bit area.

The output of the frame memory 402 is periodically processed by the D/A 403 and displayed on the monitor 404.

At this time, on the monitor 404, the image from terminal B displayed in area m2 on the monitor is displayed as a moving image, and areas ml, m3. Images from terminals A, C, and D displayed on m4 are displayed as still images. This is because while the center node 100 selects moving image information from terminal B, the frame memories 400 corresponding to terminals A, C, and D
Since nothing is written to the area of frame memory 4,
This is because fixed information from these areas of 02 will be displayed on the monitor as still images. This fixed information is the most recently written image information in each area, and therefore nothing is written in the frame memory 402 when the conference starts, so even if the conference starts, the center node Until it is selected in step 100, it will not be displayed on the display section of the corresponding monitor. This problem can be easily avoided by sequentially selecting image information from all terminals at the center node 100 as frame initialization processing when a conference is started. Furthermore, when the video information selected by the center node 100 changes, the control unit of the center node 100 controls the frame memory write area switching unit of each terminal to instruct the frame memory write area corresponding to the selected terminal. do. For example, when the selection changes from terminal B to terminal C, each terminal newly writes the output moving image information from reduction into an n-bit area starting from address a3 of the frame memory. As a result, writing to the frame memory corresponding to terminal B is stopped.

Looking at this on the screen of the monitor 404, when the selection on the center node 100 changes from terminal B to terminal C, terminal B
The area m2 that displays images from terminal C changes from a moving image to a still image, and the area m3 that displays images from terminal C changes from a still image to a moving image.

〔Effect of the invention〕

As explained above, the present invention displays image information from each terminal on one monitor when holding a video conference at multiple points, and displays only the image information from the terminal selected by the center node as a video. By displaying image information and displaying other images as still images, image information from all terminals can be displayed at the same time, providing a sufficient sense of realism when conducting multipoint video conferences. You can, and furthermore,
Since selection control can be performed from the control terminal, selection control can be performed dynamically in response to comments made during a meeting, and it has the flexibility to select images to be displayed using video information, and selection control can also be performed at the center node. For simultaneous display as in the past, decoding (hi, reduction,
There is no need to perform encoding processing, so it is economical and there is no processing delay.
It is only necessary to have a decoding means, and by having the center node control the terminal's image reduction means and frame memory write area switching means, it is possible to flexibly respond to changes in the number of participating conference terminals. .

[Brief explanation of the drawing]

FIG. 1 is a functional block diagram of an image display system for a multipoint video conference showing an embodiment of the present invention. FIG. 2 is a functional block diagram showing an example of an image reduction means of a terminal in this embodiment. FIG. 3 is a functional block diagram showing an example of the frame memory write control section of the terminal in this embodiment, and FIGS. 4 and 5 are first examples of conventional image display systems for multipoint video conferences, respectively. Functional block diagram showing the second example, FIG. 6(a)(b),
(c) is a diagram showing an example of a display displayed on a monitor. 100.200,250...center node, 101
．． 240, 261... control terminal, 111, 112,
113. 114. 201. 202. 20320
4.261, 262, 263.264...terminal transmitter, 121, 122, 123, 124, 221.222,
223,224,271,272゜273.274...
・Terminal receiving section, 131,211゜300...Analog/'digital converter (A/D), 145.233.4
03...Digital/analog converter (D/A), 1
32, 212, 260... encoding unit (encoding), 14
1,231,251,252.253,254,300
, 400... decoding unit (decoding), 142, 255,
256,257°258.301...Image reduction unit (
reduction), 143°401...Frame memory write area switching unit, 14.1232.402...Frame memory, 259,302.304...Memory, 146,23
4,404...Monitor.

Claims (1)

[Claims] In an image display method for a multipoint video conference in which a control terminal and a plurality of terminals are connected to a center node and image information from all partner terminals is displayed simultaneously between the terminals, each of the plurality of terminals A/ input image information
An A/D conversion means for D-converting; an image reduction means for performing image reduction processing on output image information of the A/D conversion means in response to a first control signal from the center node; image encoding means for encoding reduced image information and transmitting it to the center node; image decoding means for decoding the broadcast image information broadcast from the center node; and storing the broadcast image information. a frame memory, an image monitor means for D/A converting and displaying image information from the frame memory, and a second control signal from the center node to send output information from the image decoding means to each of the terminals. and frame memory write area switching means for writing into a correspondingly pre-specified area of the frame memory, and the center node transfers encoded image reduction information from the plurality of terminals from the control terminal. broadcasting means for broadcasting the selected encoded image reduction information to the plurality of terminals by selecting the first control signal and the second control signal according to the display image control signal from the control terminal; An image display method for a multipoint video conference, comprising: a control means for transmitting the second control signal to the plurality of terminals.