JPS584515B2 - 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 relates to a still image service system in which still image services are randomly generated at each terminal and sent to an image data bank to prevent the still image service to a specific terminal from being intercepted by other terminals.

Conventionally, CAI (Computer Assisted
(Aided)Instruction)
Taking into consideration the fact that moving images are not necessarily required when services such as Still image service systems using time-sharing are being attempted.

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 maintaining confidentiality on the one hand, 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 secret of communication refers to the content of the communication itself, the person communicating, or both, but according to conventional service systems, the terminal number uniquely corresponds to the person communicating,
Once the terminal number is known, the contents of subsequent communications can be completely intercepted, so in order to maintain the confidentiality of communications, it is necessary to conduct communications in such a way that the terminal number cannot be easily known.

Here, the content of the communication may be a single frame screen, or it may be presented in a connected manner on multiple screens, but if you think of it this way, the confidentiality of the communicator is maintained, and if the information has a story, the screen If the secrecy of the communication between them is maintained, most of the secrecy of the communication can be protected.

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 provides a random pattern signal generator for each terminal, and each terminal sends a random pattern signal from the signal generator at the same time as the screen request signal, and an image signal on which this random pattern is superimposed. The terminal that sent the random pattern receives the still image service.

That is, the present invention provides a random signal generator in a terminal in a still image service system having an individual uplink input line in addition to a single shared downlink video line, and the terminal sends this random pattern signal to the center at the same time as the screen request signal. Meanwhile, at the center, this random pattern signal is superimposed on the target image signal during the blanking period of the downstream image signal.

This allows the receiving terminal to receive a series of still image services by capturing only image signals whose random pattern during the blanking period matches the random pattern sent by itself.

Therefore, if you want to eavesdrop on this from another terminal, you have to predict the random pattern signal that the terminal emits every time the screen is updated, which is virtually impossible.

In this way, the terminal has a random pattern signal generator,
If the random pattern signal generated therefrom is used as a key signal for communication between the center and the terminal, the secrecy of the communicator and the context of the communication will be protected, resulting in the secrecy of the communication being protected.

It goes without saying that even if only one or a small number of terminals receive the still image service, the center must constantly send out false signals to dazzle eavesdroppers and eavesdroppers.

The present invention will be explained below with reference to FIGS. 1 and 2.

First, FIG. 1 shows the general configuration of a still image service system to which the present invention can be applied.

According to this, each of the terminals 3 to 5 includes an image capturing device 3a, 4a, 5a, an image receiving device 3b, 4b, 5b, a terminal input device (specifically, a keyboard input device, a telephone, etc.) 3
It is composed of c, 4c, and 5c.

Each terminal 3 to 5 is branch-connected to a single downlink video line 2, while a separate data line (telephone line can also be used) 6
It is connected to center 1 via.

The data line 6 is provided to improve individual services for each terminal 3-5.

However, as already mentioned, although consideration is given to individual services in such a system configuration, the confidentiality of communication is not considered at all.

According to the invention, a random pattern signal generator is provided in the terminal.

As shown in FIG. 2, for example, when the subscriber of the terminal 3 requests the next update screen from the terminal input device 3c, the random pattern signal generated by the random pattern signal generator 3d is added to it and sent to the center 1. It will be done.

When the center 1 transmits the next screen to the terminal 3, the same pattern signal as the random pattern signal is superimposed on the image signal blanking and transmitted.

On the other hand, on the terminal 3 side, when a random pattern signal was previously given to the center 1 and a screen update request was made, the same random pattern signal was set as the terminal number in the address verification device 3a' in the image capture device 3a, center 1
It will be in a state where it will be waiting for images from.

Therefore, in this state, if there is a still image signal to which the same pattern signal as the random pattern signal sent from the center 1 to the terminal 3 is present, it is captured into the image memory 3a and displayed on the image receiving device 3b.

In such a service system, the terminal number is randomly generated by the random pattern signal generator 3d, and the terminal number is 1
Since it changes from screen to screen, it is actually impossible for other terminals to completely intercept this information.

As explained above, the present invention uses a random pattern signal generated by a random pattern signal generator provided in a terminal as a terminal signal or key signal necessary for communication between a center and a terminal to provide a still image service. This is what I did.

According to the present invention, since the terminal signal is changed every time the screen is updated, it is possible to effectively maintain the confidentiality of communication.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an example of a conventional still image service system to which the present invention can be applied, and FIG. 2 is a block diagram of an example of a still image service system to which the present invention is applied. 1... Center, 2... Downlink video line,
3, 4... ...Terminal, 3a... Image capture device, 3b... Image receiving device, 3c...
- Terminal input device, 3d...Random pattern signal generator, 6...Uplink data line.

Claims (1)

[Claims] 1. When a still image signal from an image data bank is time-divisionally transmitted to multiple terminals via a single shared transmission path, each terminal transmits only the still image signal portion corresponding to its own terminal number. In the still image service method that receives still image services by importing still images, the number is assigned to each terminal when each of the terminals sends a screen request signal to the data bank, without fixing a terminal number unique to each terminal. Each of the terminals generates a random pattern signal, and the pattern signal is sent to the data bank at the same time as the screen request signal and is superimposed on the requested still image signal, while each of the terminals generates the random pattern signal. A still image service system based on the above-mentioned data bank, which selectively captures still image signals sent from the data bank via a shared transmission line to receive a still image service.