JPS584516B2 - Still image service method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an address signal or a key signal for each terminal to input still image information when a plurality of terminals receive still image information from an image data bank via a shared video transmission path. This invention relates to a still image service system that prevents still image services provided to a specific terminal from being intercepted by other terminals by randomly specifying them from an image data bank.

Conventionally, a large number of terminals access an image data bank (hereinafter simply referred to as a center) located at a certain location, resulting in CAI (Computer ASsist)
Focusing on the fact that moving images are not necessarily required when services such as ED (Aided) Instruction) are provided, a single transmission channel (broadcast radio waves or a single coaxial cable) is divided into still image frames. A still image service system is being attempted in which each terminal uses this on a time-sharing basis.

However, this service method has the disadvantage that it is not only difficult to maintain the confidentiality of communication services because it is equivalent to multiple terminals being branched and connected to a shared transmission path, but also that it is difficult to receive individual services. be.

For this reason, for individual services, consideration has been given to making it possible to set up an uplink from the terminal to the center (existing telephone lines can also be used) for each terminal, specify the requested service items, and specify the screen update interval. However, there is no consideration given to confidentiality on either side, making it extremely difficult.

Currently, an image signal with a predetermined terminal number (address signal or key signal) superimposed on the blanking part is sent from the center via a shared transmission path, and the terminal side matches the terminal number unique to its own terminal. Receive the image you created,
This is because it only records and displays it.

Therefore, the current situation is that once the terminal number is leaked, the service that the terminal is receiving will be exposed to other terminals, which is a drawback that still remains unresolved.

In general, the secrecy of communication refers to the content of the communication itself, the person communicating, or both, but in conventional service systems, the terminal number uniquely corresponds to the person communicating, and once the terminal number is known, If the terminal number is stolen, the contents of the subsequent communication will be completely intercepted, so in order to maintain the confidentiality of the communication, it is necessary to conduct the communication in such a way that the terminal number cannot be easily known.

An object of the present invention is to maintain the confidentiality of communications at each terminal by preventing the terminal number or address signal of each terminal from being easily known.

For this purpose, the present invention separately establishes a new full-duplex or half-duplex data line (telephone lines can also be used) in addition to a single video downlink transmission line to which multiple terminals are branch-connected. Each time a service is started, the terminal receives a random terminal number or address signal from the center via this data line, and during the service, the terminal number is used as a key to receive still image services. shall be.

That is, according to the present invention, the terminal number when receiving the still image service is given as a random number at the time of starting the service, and the random terminal signal is superimposed during the blanging period in the still image signal. In fact, other terminals cannot predict the terminal number, which makes it possible to maintain the confidentiality of communications.

The present invention will be explained below with reference to FIGS. 1 to 3.

As shown in FIG. 1, the system configuration for providing this type of still image service is such that still image information sent from a center 1 is transmitted on a downlink video line 2 in a time-division manner, and the required still image information is The configuration is such that multiple terminals 4 to 6 capture and record and display the data.

Each of the terminals 4 to 6 has an image capturing device 4a, 5a,
It is composed of image receiving devices 6a, 4b, 5b, 6b and terminal input devices 4c, 5c, 6c.

Among these, the general configuration of the image capturing devices 4a, 5a, and 6a is as shown in FIG. 2, as shown in FIG. The circuit 12 compares the terminal numbers, and only if they match, the image signal corresponding to the terminal number is stored in the one-frame memory 13.

The image signal stored in this way is later read out,
Although the image is displayed as an image on the image receiving devices 4b, 5b, and 5b, this situation is almost the same as in the conventional case.

What is important here is that the setting terminal number in the setting device 11 is variable.

Conventionally, this set terminal number has been fixed, but according to the present invention, a random terminal number is set, thereby solving the drawbacks of the conventional method.

A random terminal number is set in the setter 11 according to an instruction from the center 1.

When a terminal that wants to receive a service calls the center 1 from the terminal input device via the individual data line 3, the service is started. It is instructed to the terminal via the terminal, and is set in the setting device 11 mentioned above.

Therefore, the terminal will select and display only the image signal corresponding to the terminal number in the setting device 11, but even if you try to receive the service again after the service has ended, a random terminal number will be displayed as well. Therefore, due to the random nature of the terminal number, other terminals cannot predict the terminal number of the terminal and cannot intercept communications to the terminal.

3a and 3b show the flow of the service start procedure in the conventional service method and the service method according to the present invention, respectively, but no particular explanation is required for this.

As explained above, the present invention provides a method in which a plurality of terminals are connected to a single transmission path through which still image information from a center is transmitted.
When these terminals use a single transmission path in a time-sharing manner, each terminal is given a random terminal number at the start of receiving the still image service, and based on that terminal number, It is designed to receive still image services.

According to the present invention, the terminal number specified by the center is random, and because of the randomness, the own terminal number is not easily known to a third party, and therefore, the own terminal number is not easily known to a third party. This has the effect of effectively preventing communications from being intercepted.

[Brief explanation of the drawing]

FIG. 1 is a system configuration diagram for implementing the still image service method according to the present invention, FIG. 2 is a specific circuit configuration diagram of the image capturing device in FIG. 1, and FIGS. FIG. 3 is a diagram showing a flow of a service start procedure in a service method, a service method according to the present invention. 1... Image data bank (or center),
2...Single downlink video line, 3...Individual data line (or telephone line), 4-6...
Terminal, 4a, 5a, 6a... Image capture device, 4b, 5b, 6b... Image receiving device, 4c,
5c, 6c...terminal input device.

Claims (1)

[Claims] 1. When time-divisionally transmitting still image signals from an image data bank to multiple terminals via a single shared transmission path, each of the terminals captures only the portion of the still image signal corresponding to its own terminal number. In the still image service system where still image services are received, the number is presented as a random number from the image data bank each time the still image service starts, without fixing a unique terminal number to each terminal. The still image service system is characterized in that each of the terminals receives a still image service using the presented number as its own terminal number.