JPH03262248A - Television conference communication system for quasi-moving picture television telephone set for analog telephone line - Google Patents

Abstract

PURPOSE:To attain a TV conference by a quasi-moving picture TV telephone set through the use of an analog telephone line by allowing each TV telephone set to compose and extract a cyclic frame based on a synchronization frame as a reference. CONSTITUTION:A BTV telephone set 11 and a CTV telephone set 21 detects a synchronization frame 9 among cyclic frames sent from an ATV telephone set 1 respectively. Then the TV telephone sets 1,11, 21 send their own picture frame to the cyclic frame unconditionally at a delayed time in response to the sequence of own sets. Thus, the composition of the cyclic frame is finished. When the composition of the cyclic frame is made complete, frames 6-8 are circulated on the analog telephone line among the telephone sets 1,11, 21. Then each telephone set extracts only a desired video frame based on the synchronization frame and it is observed on a monitor 23.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a semi-video video telephone set for analog telephone lines that conducts a video conference between three or more semi-video telephone sets connected by an analog telephone line. Concerning a video conference communication system.

[Conventional technology]

Conventionally, when holding a video conference between three or more parties using a semi-video video telephone, an I5DN digital line for video conferences has been used.

FIG. 5 is an explanatory diagram of a conventional l5DN-based quasi-video teleconference communication system.

First, on the left side of the figure are semi-video video telephones A (31,), B (32), which are participating in a video conference.
There are C (33) and D (34), and their respective videophones are connected to the multipoint conference control notebook (35) on the right side of the figure.
)It is connected to the.

The connection line in this conventional example is a digital line.

Therefore, the upstream and downstream channels are independent, and line control can be easily performed.

Next, the operation of the conventional semi-video teleconference communication system in the I5DN system will be explained based on FIG.

FIG. 5 shows the distribution relationship and status of image frames from each video telephone when a video conference is held between four parties.

First, let's focus on videophone A (31). From this video phone A (31), a multipoint conference control node (3
5), consecutive frames (AI-A2-A3-) are sent. In addition, from the multipoint conference control node (35), the circulating frames for all participants excluding the image of video phone A (31) are sent to the circulating frame (Bl-), which is thinned out corresponding to the circulating frame. CI-DI--B4-C4-D4-) is received by videophone A (31).

Other videophones B (32), C (33), D (34)
), similarly, the circuit frame of the person other than the concerned party is accepted. The cyclic frames thus delivered are assembled separately for each destination.

Further, FIG. 6 is a diagram illustrating the disassembly processing of received frames within the quasi-video video telephone.

From the right side of the figure, the received cyclic frame (36) of the parties other than the party concerned is input to a generator (37) that decomposes the frame and generates fields. The output is then made to each frame/field memory (38) and assembled field by field. These assembled fields are input to the monitor (39) corresponding to each field, and the video conference can be held while viewing the screens of all conference participants.

Note that in this case, the screen of one monitor is sometimes divided into a plurality of parts to display images.

[Problem to be solved by the invention]

As mentioned above, conventional video conference communication systems include l5
Since a DN-based digital line is used, line control is easy, and even in the transfer of cyclic frames, an image frame collection and delivery method that takes line efficiency into consideration is adopted.

As described above, although conventional video conference communication systems can easily perform line control and transfer processing of circular frames, they are expensive because the line switching equipment etc. are very complex, and because they use digital lines, they are difficult to use. The problem is that the range is limited.

Therefore, there is a desire to realize quasi-video video conferencing using analog telephone lines that are inexpensive and widely available, but unlike digital lines, line switching equipment is not complicated, so
It was thought that it would be extremely difficult to realize videoconferencing using quasi-video technology similar to digital lines.

This invention was made with the aim of solving the above-mentioned problems, and it is possible to achieve something similar to quasi-video teleconferencing using conventional digital telephone lines at low cost using analog telephone lines. The purpose of this invention is to provide a video conference communication system for a quasi-video video phone for analog telephone lines.

[Means to solve the problem]

The video conference communication system for a quasi-video video phone for analog telephone lines according to the second invention is such that when a conference is held between video phones of three or more parties, the transmission order of circular frames circulating on the analog telephone line is changed to C8MA/ A cyclic transmission order determination step determined by the CD method, and each video telephone transmits its own image frame to a predetermined position of the cyclic frame corresponding to the determined cyclic transmission order, with reference to a synchronization frame included in the cyclic frame. The present invention is characterized by comprising a cyclic frame assembling step and an image display step in which each video telephone extracts only necessary image frames from the assembled cyclic frames based on a synchronization frame and displays a quasi-moving image.

[Effect]

The video conference communication system for semi-video video telephones for analog telephone lines according to the present invention changes the order of cyclic transmission of cyclic frames between video telephones to C8MA/CD (Carri).
er 5ense Multiple Acce
ss With Co11ision Dete
By determining the order using the ction) method, it is possible to smoothly determine the order of video telephones connected to a common analog telephone line.

Then, each video phone is controlled by a conventional digital telephone line by transmitting and assembling its own image frame to a predetermined position of the circulating frame according to the determined order, using the synchronization frame in the circulating frame as a reference. Functions previously handled by nodes can now be distributed to each analog telephone, allowing the use of regular analog telephone lines.

Furthermore, by extracting necessary image frames from the circulating frames circulating on the analog telephone line, each video telephone can conduct a video conference while viewing images of desired conference participants on a monitor.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a video conference communication system for a semi-video video phone for analog telephone lines according to the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory diagram of a video conference communication system according to an embodiment of the present invention.

As shown in Figure 1, 3
A videophone (1) for each telephone used for video conferencing.
, B videophone (11), and C videophone (21).

The A video telephone (1) includes an audio circuit section (2), a quasi-video television monitor section (3), and a line echo canceller processing section (4) that interfaces with an analog telephone line (5).

Similarly, the other B videophones (11) and C videophones (21) also have an audio circuit section (12),
(22), Semi-video TV monitor section (13), (23
), line echo canceller processing section (14), (
24) respectively.

And each of these videophones (1), (11)
, (21) are directly connected by an analog telephone line (5) via a conventional analog line switch (not shown).

Then, from each videophone, a circulating frame (6),
(7) and (8) are analog telephone lines (5
) and is sent out to perform patrols.

In the video conference communication system configured as described above, the video conference communication method of this embodiment will be described below.

Here, we will discuss an example in which a quasi-video video telephone set using an analog telephone line is used, and a video conference is held between three parties, starting from a two-party conversation mode and then transitioning to a three-party conference mode. This is what is shown.

Conventionally, in two-party dialogue mode, it has been possible to make a semi-video videophone call using an analog telephone line.

Therefore, in FIG. 1, during the two-party dialogue mode between videophone A (1) and videophone B (11), videophone A (1) is contacted by videophone C (21) by means such as call waiting or a parent-child phone call. Assume that there is a request to hold a meeting with the participation of a third party.

In this case, in the conventional example, the C videophone (21) could not participate in the discussion between the A videophone (1) and the B videophone (11).

However, in this embodiment, the A videophone that received the request (
1) Become a dummy filler and inform the other party of the conversation, B video phone (11).

Thereafter, by pressing a conference button provided on each video telephone and a number button corresponding to the number of people in the conference, an order determination mode is entered in which the order of cyclic transmission of cyclic frames to be circulated between the respective telephones is determined.

At this time, telephone A (1), which is the leader telephone, sends out a leader frame onto the analog telephone line.

This leader frame is a cyclic frame composed of a synchronization frame and an image frame to be sent by the leader telephone (telephone A).

Next, the determination of the cyclic transmission order of each participating telephone is determined by the CSMA
In the /CD system, decisions are made by competing among telephones for order priority.

This C8MA/CD system is equipped with a mechanism that detects collisions with data from other terminals on line 2, and when data collisions occur, transmission is stopped and retransmitted after a certain period of time. This is an access method that reduces the probability of re-collision.

FIG. 3 is a diagram illustrating the sequence number acquisition competition process in the cyclic frame, and FIG. 4 is a diagram illustrating the state after the sequence number acquisition competition in the cyclic frame.

As shown in FIG. 3, in the order determination mode, accesses shown by arrows from videophones C and B are made to the frames sent by videophone A, which is the leader telephone. .

As shown in the figure, the leader frame sent out by the A video phone is composed of a synchronization frame (9) and a subsequent image frame (AO) of the A video phone. For this reason, even if videophone C and videophone B access first, they will not be able to obtain a ranking because there is an image frame of videophone A. However, when it comes to the edge of the image frame (AO) of the A video phone, the access of the B video phone is successful (the arrow makes a U turn), and the acquisition of the second ranking is recognized (BO). Then, the C videophone obtains the third ranking after the B videophone (CO).

In this way, after the competition for obtaining the cyclic number by C8MA/CD, as shown in FIG. .

The sending position of (CO) is secured.

Each videophone automatically starts operating in a synchronous mode (conference mode) when its ranking is determined.

That is, as shown in FIG. 4, the B videophone and the C videophone each detect a synchronization frame (9) (indicated by an upward arrow) with respect to the circulating frame sent by the leader telephone. Then, each video phone unconditionally sends its own image frame to the circulating frame at a delayed time according to the order in which each video phone has it.

In this way, the assembly of the circulating frame 12 as shown in FIG. 2 is completed. Note that there is an idle period (10-1) between the image frames sent from each videophone.
, (10-2), and (10-3) are provided to include the electrical transmission time to the other end of the line.

As mentioned above, when the assembly of the patrol frame is completed, each videophone (1), (
The cyclic frames (6), (7), and (8) circulate on the analog telephone line between 11) and (21).

Each video phone can extract only a desired image frame using the synchronization frame as a reference.

For example, if you want to view an image from videophone A (1) on videophone C (21) in FIG. By selectively extracting images and assembling them as shown in (...), the images can be viewed on a monitor (23).

Further, after the video telephone A, which is the leader telephone, has passed the circuit time corresponding to the number of people participating in the conference, it continues to perform a sequence of retransmitting the circuit frame including the synchronization frame and its next image frame.

Furthermore, in this embodiment, as shown in FIG.
, (24) are inserted, so that the frame cannot be taken out while each video telephone is engaged in assembling the traveling frame.

As described above, in this embodiment, the frame delivery, which is performed by the conventional central control node of the I5DN system, is automatically performed in a distributed manner on each video phone side. For this reason,
It is now possible to conduct video conferences using quasi-video video telephones even on analog telephone lines that do not have the complicated circuit switching equipment used on digital lines. As a result, it is possible to conduct video conferences using quasi-video video telephones using analog telephone lines that are inexpensive and widely available.

〔Effect of the invention〕

As explained above, the video conference communication system for a quasi-video video phone for analog telephone lines according to the present invention circulates a cyclic frame including a synchronization frame on an analog telephone line that connects video phones of three or more parties. Since the video telephone set is configured to assemble and take out the cyclic frame based on the synchronization frame, it has become possible to conduct video conferences using the semi-video video telephone set using an analog telephone line. The availability of analog telephone lines has made it possible to create a video conference communication system that is inexpensive and can be used over a wide range of areas.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a video conference communication system according to an embodiment of the present invention, FIG. 2 is a configuration diagram of a cyclic frame according to an embodiment of the present invention, and FIG. 3 is a sequence number acquisition competition process in a cyclic frame. FIG. 4 is an explanatory diagram of the state after the sequence number acquisition competition in the cyclic frame, and FIG. 5 is the conventional l5
FIG. 6, which is an explanatory diagram of a communication system for a DN semi-video teleconference, is a diagram of the disassembly processing of received frames within a conventional semi-video video telephone. In Figure 1, (1) is A video phone, (11) is B video phone, (21) is C video phone, (2),
(12), (22) are audio circuit sections, (3),
(13), (23) are quasi-video TV monitor parts, (
4), (14), (24) are line echo canceller processing units, (5) are analog telephone lines, (6),
(7) and (8) are cyclic frames. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] In a video conference communication system in which video telephones transmit and receive quasi-video data via an analog telephone line, when the transmission and reception of quasi-video data is started between three or more video telephones, a video telephone circuit that circulates over the analog telephone line is provided. a cyclic transmission order determining step of determining the transmission order of the cyclic frames to be transmitted according to the CSMA/CD method; a cyclic frame assembling step in which each image frame is sent to a position; an image display step in which each video phone extracts only necessary image frames from the assembled cyclic frames with reference to the synchronization frame and displays a quasi-moving image; A video conference communication system for a quasi-video video phone for analog telephone lines, characterized by comprising: