JPS5936302B2 - Character transmission display method - Google Patents

Description

[Detailed Description of the Invention] This invention provides a character transmission display in which a remotely installed display terminal accesses an information center via a communication line, and desired character and graphic information is transmitted from the information center and displayed on the terminal. Regarding the method.

In the conventional system of this kind, as shown in FIG. 1, the subscriber dials by operating the terminal operating section 12 in the subscriber terminal device 11, which has the same functions as a normal telephone, in the same way as in a normal telephone call. Then, the information center 17 is called through the terminal control section 13, the terminal modem section 14, the subscriber exchange 15, and the center exchange 16. As a result, the subscriber terminal device 11
is connected to an information center 17 by a subscriber exchange 15 and a center exchange 16. Next, when the subscriber inputs a code indicating the desired information through the terminal operation unit 11 using the selection button, the code is sent to the terminal modulation/demodulation unit 1 from the terminal control unit 13.
4, the signal is converted into a transmission signal and transmitted to the information center 17 via the terminal exchange 15 and the center exchange 16.

In the information center 17, the transmitted signal is transmitted to the center modulation/demodulation section 1.
8 and decoded by the center control section 19. The center control unit 19 searches the information file 21 based on this code and extracts desired information. The extracted information is sent to the subscriber terminal device 11 in the form of a code via the center modulation/demodulation unit 18, the center exchange 16, and the terminal exchange 15. In the subscriber terminal device 11, the transmitted code is temporarily stored in the code refresh memory section 22, and then the code is decoded, the character and graphic pattern corresponding to the code is taken out from the pattern generation section 23, and the pattern is displayed on the display section 24. Supplied to and displayed.

In this way, in the conventional system, the display information is encoded and sent between center terminals, so the amount of transmission signal is small, but the pattern generation section 23 that stores the pattern information to be displayed on the terminal device 11 is This has the disadvantage that the terminal device 11 is expensive. On the other hand, as shown in FIG. 2, a pattern generation section 25 is provided in the information center 17, and
A device equipped with a dot refresh memory 26 for one screen has also been proposed. The procedure is similar to that shown in FIG. 1 until the subscriber makes a call using the terminal operation unit 12, calls the information center 17, and sends the desired information to the center 17 in code. When the information center 17 searches for desired information from the information file 21, it extracts the character and graphic patterns corresponding to the information from the pattern generation section 25, converts it into a one-screen pattern signal, and then sends it to the center modulation/demodulation section 18,
It is sent to the subscriber terminal device 11 via the center exchange 16 and the subscriber exchange 15.

When the subscriber terminal device 11 receives the pattern signal for one screen, it temporarily writes it into the one-screen dot refresh memory 26, and then continuously reads it from there and supplies it to the display unit 24 to display characters and figures. do. In this conventional method, character and graphic patterns are transmitted as pattern signals, so the amount of broadcast signals increases, it takes time to transmit one screen, and the storage capacity of the J screen dot refresh memory 26 placed on the terminal side is reduced. Since the number of devices increases, the disadvantage is that the terminal device becomes expensive.

In order to eliminate these drawbacks, the present invention transmits image information in the form of compressed codes on the communication path, and decodes it on the terminal side without using a pattern generator to obtain a display pattern. The present invention provides a character sending and displaying method that allows for easy configuration of a terminal device.

FIG. 3 shows an embodiment of the character shift display system according to the present invention, and parts corresponding to those in FIGS. 1 and 2 are given the same reference numerals.

A subscriber makes a call using the terminal operation unit 12, and the information center 1
7 and transmitting the desired information in code to the center 17, the procedure is similar to that of the conventional method described above.
When the information center 17 searches for desired information from the information file 21, the control section 19 transfers one screen worth of information in the form of character codes to the conversion center 28. Under the control of the control section 29, the conversion center 28 sequentially reads out character pattern data from the character pattern generation section 25 in correspondence with each character sent as a code from the information center 17. In this case, for example, if the display screen consists of characters as shown in FIG. 4, the character pattern data sent from the conversion center 28 to the subscriber is only the character pattern corresponding to character position 33, The patterns in the spaces 34 and 35 are not transmitted. By doing so, it is possible to reduce the amount of data to be sent and shorten the time required to broadcast the screen, and it is also possible to reduce the storage capacity of the refresh memory in the terminal. The pattern data of the character position 33 to be sent is encoded by the character signal encoding section 31 and sent. For example, when the character to be sent is the "sentence" shown in FIG. as S in Figure 6. is read out,
Next, scanning lines 11, 12, ......, 117
corresponding to each of the patterns Sl, S2,...
. . , Sl7 are read respectively. The character pattern data read out in this way is stored in the character signal encoder 3.
1 and sent to the subscriber terminal device 11 side through the control section 29 and the modulation/demodulation section 18. The encoding format of the character pattern data performed by the encoding unit 31 at this time will be described later. The character pattern data sent in this manner is temporarily written into the refresh memory section 36. The writing units are done in the order of the characters being broadcast. Next, the character pattern data written in this manner is sequentially read out in the row direction of the display screen and decoded by the decoding section 37 to form a display image signal.

In other words, as shown in Figure 4, "Character display...
When displaying a character string arranged like ``...'', character pattern data S corresponding to the first scanning line 10 of the character ``character'' is first displayed. The code corresponding to ``character'' is read out from the refresh memory 36, the timing is set for a time corresponding to the character interval 34, and then the first scanning line 1 of ``character'' is read.
Read the character pattern data corresponding to . Similarly, the first scanning line of the character string corresponding to that line is sequentially read out,
A display image signal is created by decoding. When the character pattern data for the first scanning line is read out, the character pattern data for the second scanning line 11 of the displayed character string is read out, and the character pattern data for the second scanning line 11 is read from the refresh memory 36 in the same manner as described above. The pattern data is read out and decoded to create an image signal for display.

When the display of the first line of the display character string is finished in this manner, the control unit 13 takes a timing corresponding to the line spacing 35 and moves on to displaying the character string of the second line. By performing such display control, it is only necessary to store in the refresh memory 36 the character pattern of only the part of the characters necessary for display, and the storage capacity of the refresh memory 36 can be reduced. The readout control of the refresh memory 36 is performed by the control unit 1.
However, by constructing the refresh memory 36 with randomly accessible memory elements, this operation can be easily implemented using known digital control techniques. Next, the encoding format of character patterns by the encoding unit 31 of the conversion center 28 will be described.

Normally, the character pattern displayed on a display device etc. is based on vertically adjacent rasters, such as rasters 10 and 1 in FIG.
There is a strong correlation with 1. Therefore, by encoding using this correlation, the amount of transmitted codes can be compressed. In other words, the position of the information change point of each scanning line, that is, the position of each change point from white to black and from black to white, is relative to the pixel immediately above, which is the reference, and the pixels before and after it, or the previous change point on the same scan line. Encode using distance. FIG. 7 is a diagram explaining this encoding principle, and the encoding target pixel PO of the encoding line 1n1+1 is 3 m of the adjacent reference line 1m.
Pixels P1 to P3 and the encoding target pixel P on encoding line 1m+1.

The relationship with the change point 38 immediately before is examined. Encoding target pixel P. Pixel of interest P on the scanning line directly above, that is, the reference line 1m. Pixel P2 directly above, pixel P1 immediately above
, if any one of the pixels P3 immediately above and after is a character pixel, that pixel is selected as the reference point. If there is no such pixel, the target encoding point P is on the encoding scanning line 1n1+1. The change point pixel 38 immediately before is taken as a reference point, and encoding is performed using that reference point and the distance 11 from there, or the target encoding point P of the encoding scanning line 1n1+1. If there is no change point before, take the start position of the scanning line 1m+1 or the end position of the scanning line as the reference point, encode according to the distance from there, and use the code with the shortest code length among them. do. If the encoded pixel of interest is only one isolated point pixel, that is, an RZ pixel, the code assignment is changed depending on whether it is the beginning or end of consecutive black or white pixels, that is, if it is an NRZ pixel.

FIG. 8 shows such encoding. Reference scan line distance +
O, +l, and -1 are the target encoding points P in FIG. 7, respectively. On the other hand, they correspond to P2, P3, and Pl, and in the case of isolated pixels, they are encoded as 100, 1010, and 1011, respectively. The distance to the previous change point on the encoded scan line is given by 1, and F(1) is a binary code indicating the length l. Although it is not shown in Figure 8, "0" is added as a code to indicate the beginning of a character (the left end of the character pattern).
The code that indicates the end of a line on the display screen is ``F''.
If there are seven consecutive Tllllllll'2 codes, the code Tllllll'2 is used. FIG. 9 shows an example in which the character pattern "sentence" shown in FIG. 5 is encoded.

That is, the first scanning line 1. If you look at it, it doesn't show the beginning of the letter O
Continuing from ゛, since there is no reference scanning line, for the 8th isolated pixel, the starting position of the Q scanning line is used as a reference, and since l〉1, from Fig. 8, ゛1100゛ is added, and further 17
Therefore, F(1)-111 is added. The second scanning line 11 is the first scanning line 1. Since the same pixel point on the reference scanning line is closest to the same pixel, the eighth
From the figure, it is encoded as ``100'', and since it is the beginning of a character, ``O'' is added in front of it.Others are encoded in the same way, but only the fifth scanning line 14 is not an isolated pixel. It is a continuous black pixel, and l≧1 for NRZ pixels, and the codes are 1101' and l-0 to 3000.The sixth scanning line 15 is the fifth from the beginning on that scanning line. "1100" and "100" are used to indicate the pixels of
Therefore, "1100'5" and "6101" are used. The following is encoded in the same manner. With the above encoding, 1
To express a character pattern of 6 x 18 dots as is, 288 bits were required, but only 141 bits were needed, approximately 1
/2 code amount.

It is easy to imagine that the character pattern encoded in this manner can be decoded by the decoder 37 of the terminal device 11 and converted into a display signal as a display character pattern.

In the above configuration, patterns corresponding to the actual characters shown in FIG. 6 are stored in the character pattern generating section 25, and the character patterns are encoded in the encoding section 31 as needed, to generate codes as shown in FIG. However, the character pattern generator 25 is configured to directly store character codes as shown in FIG. 9, and send out the codes in response to search information. 25 and the encoding unit 31 can also have a simple configuration.

Furthermore, since the display pattern is encoded as a pattern signal, it is possible to encode not only characters but also symbols, and it is clear that simple figures can be displayed by combining these symbols. Dew.

Furthermore, as encoding methods for character patterns, RZ pixels and NRZ
Although the image signals are classified into pixels and encoded, other encoding methods may be used, such as an image signal encoding method that is often used in the wide transmission of facsimile signals and the like.

As explained above, according to the character transmission and display method of the present invention, the displayed character information is converted into a pattern signal, data is compressed, encoded, and distributed, so a character pattern generator on the terminal side is not required. Therefore, the price of the terminal device can be reduced.

It also has the advantage of reducing the amount of text messages, requiring less time for texting one screen, and increasing conversational responsiveness in information searches.

[Brief explanation of drawings]

FIGS. 1 and 2 are block diagrams showing a conventional character transmission display method, FIG. 3 is a construction diagram showing an example of a character transmission display method according to the present invention, and FIG. 4 is a block diagram showing a character transmission display method according to the present invention. Figure 5 is a diagram showing the display format, and Figure 5 is a diagram that breaks down characters into pixels to explain the encoding order of displayed characters. Figure 6 is a diagram showing the display format.
Figure 7 is a diagram showing the character pattern data shown in the figure, Figure 7 is a diagram showing pixels on the reference scanning line and encoding scanning line to explain the principle of encoding character patterns, Figure 8 is code assignment. FIG. 9 is a diagram showing an example of encoding the characters shown in FIG. 5. 11: Terminal device, 12: Terminal operation section, 13: Terminal control section, 14: Terminal modem, 15: Subscriber exchange, 16: Center exchange, 17: Information center, 18: Center modem, 19: Center control section , 21: Centafail, 24:
Display unit, 25: Character pattern generation unit, 28: Conversion center, 29: Conversion center control unit, 31: Character signal encoding unit,
36: code refresh memory, 37: decoding section.

Claims (1)

[Claims] 1. An information center consisting of a center file that stores search information, a search control section that searches for search information requested by a terminal and sends out the search information as a code, and at least a character pattern code generation section, A conversion center that is supplied with the code, converts it into a character pattern code with information compression using the correlation of the character patterns, and sends it out; and a conversion center that stores the character pattern code sent from the conversion center in correspondence with the displayed character pattern position. The refresh memory decodes the pattern code from the refresh memory for display character positions, and at positions where characters are not displayed, such as between characters and lines, a margin signal is inserted at the appropriate timing to generate a display signal for one screen. a decoding unit to obtain the signal, a display unit to which the signal from the decoding unit is supplied and displaying the signal as a character symbol, etc.;
A character transmission and display system comprising a terminal device including an input operation section that inputs input information and sends it to the information center, and a terminal control section that controls each of these sections.