JPS62147887A - Video communication network - Google Patents

Abstract

PURPOSE:To retrieve and distribute a still picture that include a high-definition picture and a fine character and to shorten a retrieval response time by constituting the titled network with a terminal, a terminal-side signal switching circuit, a signal decoding circuit, a transmission line, a station-side signal switching circuit, a signal synthesizing circuit, a broadcasting signal receiving circuit, and the station. CONSTITUTION:A broadcasting standard television signal received by the broadcasting signal receiving circuit 8 is transferred to the terminal 1-side through the transmission line 4, and detected by the terminal-side signal switching circuit 2 to be transferred to the terminal 1. When a still-picture service is selected at the terminal 1, a retrieval signal is transmitted to the center 7 through the transmission line 4 and the station-side switching circuit 5. In the station 7, a retrieved digital still picture is taken out, and the data is divided into blocks of suitable length by the signal synthesizing circuit 6. And the resulting data is converted to an analog waveform, and inserted is a video signal by substituting the video-signal block of respective horizontal scanning lines of the standard television signal. The result is supplied to the terminal 1 via the circuit 5, the transmission line 4, the circuit 2, and the circuit 3.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Description of the field to which the invention pertains The present invention relates to a video communication network, particularly a video communication network that provides a searchable program delivery service using standard television signals, and which provides digitalized still images. The present invention relates to a video communication network having means for also allowing data to be delivered.

(2) Explanation of the conventional technology Video communication that provides searchable program delivery service (8 networks include two-way CATV network 1 video response system (VR3),
There is a data broadcasting system or a videotex network such as Captain. With bidirectional CATVAN and vRs, it is also possible to transmit still images, and the search response time can be extremely shortened. It is difficult to display etc. On the other hand, there are data broadcasting systems and videotex networks that digitize and distribute still images.

Although it is possible to display high-definition still images and fine text depending on the device's capabilities, it has the disadvantage that it cannot deliver standard TV signals over the same network, requires an expensive modem, and has a slow search response time. There are problems such as slowness.

(3) Purpose of the Invention The present invention eliminates the shortcomings of the above-mentioned two-way CATV, VR3, data broadcasting, and Videotex networks, and provides a network capable of delivering standard television signals simultaneously with digitalization that includes high-definition screens and fine text. The present invention enables the construction of a video communication network that enables the search and delivery of searched still images and realizes an extremely short search response time. The present invention will be described in detail below with reference to the drawings.

(4) Explanation of the structure and operation of the invention FIG. 1 shows an embodiment of the present invention.

In this embodiment, terminal 1. Terminal side signal switching circuit 2. Signal decoding circuit 3. Transmission line 4. Center side signal switching circuit 5° signal synthesis circuit 6. It consists of a center 7 and a broadcast signal receiving circuit 8.

When performing a normal program distribution service, the center side signal switching circuit 5 is connected to the broadcast signal receiving circuit 8 side, and the received broadcast standard television signal is sent to the terminal 1 side via the transmission line 4, and the terminal side signal switching circuit 5 is connected to the broadcast signal receiving circuit 8 side. 2 detects that it is a standard television signal and sends the received signal to terminal 1 as is. terminal l
has a search function for the center, and can select not only the standard television signal service (still picture service).The operation of this embodiment when the still picture service is selected is as follows.

A search signal inputted from the terminal 1 is sent to the center side through the transmission path 4, switches the center side switching circuit 5 to the center side, and transmits the search contents to the center 7. Center 7 is
The retrieved digitized still image is taken out and supplied to the signal synthesis circuit 6. In the signal synthesis circuit 6, the center 7
Divide the digitized still image data given into blocks of appropriate length (for example, 200 bits each), transform this into an analog waveform with a time width of 53 μsec at a binary or multilevel level, and convert it into a standard television signal. The video signal is inserted in place of the video signal in the video signal section of each horizontal scanning line except for the vertical blanking period. The signals synthesized as described above are shown in scanning lines No. n and No. n + l in FIG. 2. At this time, the signal synthesis circuit 6 simultaneously inserts a pulse signal as shown in FIG. 2 into the No. and i scanning lines during the blanking period to indicate insertion of digitized still image data.

The signal generated by the signal synthesis circuit 6 as described above is transmitted to the center side signal switching circuit 5. The signal is sent to the terminal side signal switching circuit 2 via the transmission line 4. The terminal side signal switching circuit 2 detects the scanning line No. i, and if a pulse waveform as shown in FIG. A signal is supplied to the signal decoding circuit 3.

If the pulse waveform is not present, the signal is directly supplied to the terminal 1.

In the case of digitized still image data, the signal decoding circuit 3 extracts the still image data excluding the vertical and horizontal blanking portions,
Furthermore, this data is decoded into a desired still image, which is supplied to the terminal 1 and displayed. At this time, if the terminal has the capability, it is possible to reproduce and display high-definition screens and fine text that cannot be expressed with standard television signals. Also, as described above, when digitized still image data is divided into blocks and inserted into the video portion of a standard television signal for transmission.

It is possible to increase the transmission speed (for example, 200
b/scanning line, it is approximately 3 Mb/s).

Compared to the 4800 b/s used by Videotex or 64 Kb/s in 15DN, it is possible to significantly shorten the high-speed bellow search response time.

When inserting digitized still image data into the video portion of a standard television signal, bits within a range that satisfies the video signal time width and signal band characteristics of the standard television signal are not required in units of 200b as described in this embodiment. It is fine if it is a number. Inserting data beyond the video signal part is effective in increasing the amount of transmitted data, but since the waveform differs from the standard TV signal, It becomes impossible to share the various transmission devices and terminal side circuits, and a dedicated circuit becomes necessary.

(5) Description of effects As described above, according to the present invention, high-definition screens that cannot be expressed with standard television signals or still images containing fine text can be displayed through a network that provides video distribution services using standard television signals. Since distribution services are possible and the search response time can be greatly reduced, it is possible to ensure superior service quality compared to Videotex services that use telephone networks. Furthermore, since it can coexist with standard television signals, users can receive both services on the same terminal network, making it highly economical.

[Brief explanation of drawings]

Figure 1 is a network configuration diagram of an embodiment of the present invention, Figure 2 is a network configuration diagram of an embodiment of the present invention.
The figure shows an example of a transmission waveform when the present invention is implemented. ■...Terminal, 2...Terminal side signal switching circuit, 3...
Signal decoding circuit, 4... Transmission line, 5... Center side signal switching circuit, 6... Signal synthesis circuit, 7... Center, 8
...Broadcast signal receiving circuit.

Claims (1)

[Claims] A center that provides a searchable program distribution service using standard television signals (for example, NTSC signals), a terminal that searches for the center, receives and displays the standard television signal from the center, and In a video communication network consisting of a network that transfers search signals and standard television signals sent and received between terminals, in addition to means for transmitting normal standard television signals to the center side, digitized still image data is also sent to the center as a standard. Provide a means for converting and inserting a waveform deemed to be a video signal into the portion of the television signal excluding the vertical and horizontal blanking periods, and transmitting it to the terminal in the same manner as a normal standard television signal; converting the video portion of said signal to obtain the original digitized still image data, and providing means for decoding and displaying the same; The center and terminals are equipped with a means for inserting a signal at the center to identify whether it is a television signal or a signal converted from digitized still image data, decoding this signal at the terminal, and switching the video processing method. A video communication network characterized by: