JP3190230B2 - FM multiplex information processing apparatus and method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an FM multiplex information processing apparatus, and more particularly to an in-vehicle FM multiplex information processing apparatus for receiving and displaying traffic image information such as traffic accidents and traffic jams from an FM multiplex broadcasting station in real time.
The present invention relates to an M multiplex information processing apparatus and a method thereof.

[0002]

2. Description of the Related Art Conventional GPS (Global Positioning Sys
A car navigation system that uses tems) provides position information for route guidance. However, in order to determine a route more efficiently, in addition to the position information, traffic information such as traffic accidents and traffic jams that change every moment is required. VICS (Vehicle Information and Communicat
The ion System) aims to provide drivers with the necessary road traffic information and parking information at any time and in any desired form in order to respond to the above demands, and thereby to utilize the road network efficiently. It is a system that did. To achieve this, FM multiplex broadcasting, radio beacons, optical beacons, etc. are appropriately used as new information providing media.

FIG. 18 schematically shows an example of a VICS system configuration. In FIG. 18, the VICS center 1 transmits road traffic information (travel time, traffic congestion, accident information, etc.) and other related information (parking vacancy status, etc.) obtained in real time from, for example, Japan Traffic Information Center.
The information is transmitted to the center of each information providing medium, that is, the FM multiplex center 2, the radio wave beacon center 3, and the optical beacon center 4.

In each of the centers, the information obtained is edited and processed for each medium, and the edited information is transmitted to each transmission medium, that is, an FM broadcast station 5, a radio beacon 6, or an optical beacon 7.
Send to The vehicle 8 receives the traffic information emitted from each transmission medium by the corresponding on-vehicle receiver. The FM broadcasting station 5 has a service area of a wide area having a radius of several tens of kilometers, and the radio beacon 6 and the optical beacon 7 have a service area of an intermittent minimum zone of several tens of meters and several meters, respectively.

FIG. 19 shows the principle configuration of a conventional FM multiplex information processing apparatus. In FM multiplex broadcasting, NH
Character data and graphic data relating to the traffic information are spatially multiplexed and broadcast using an unused portion of a radio band assigned to each FM broadcasting station such as K or commercial broadcasting. Vehicle 8 (FIG. 1)
The FM multiplex broadcast receiver mounted on 8) separates a signal received from the FM multiplex broadcast station into a conventional FM audio signal and a data signal such as text and graphics, and obtains the latter FM signal obtained therefrom.
The multiplex information 10 is temporarily stored in the memory storage unit 11 as it is. Thereafter, the FM multiplex information 10 is displayed on a predetermined display 12.

[0006] The memory storage unit 11 stores a data RAM (DRA) for temporarily storing received data as it is.
M) and the DRA when a screen display request is made
An image RAM (VRAM) that converts the corresponding data from M into screen data and stores the data is stored on the display 12, and the contents of the VRAM are displayed on the display 12.

FIG. 20 shows an example of a method of displaying FM multiplex information. So-called simplified graphic information is used for road traffic information sent by FM multiplex broadcasting. The simplified graphic information includes a fixed sketch data portion (level 2 macro data) schematically representing a divided map or a road as shown in FIG. 20A and a traffic congestion section as shown in FIG. And a time-varying overwrite data section (level 2 page data) that specifically indicates the location where the accident occurred.

The road traffic information for one screen is shown in FIG.
0 (c) is created by superimposing the latter page data on the former macro data. The fixed level 2 macro data and the variable level 2 page data are transmitted from the FM broadcasting station 5 (FIG. 18) at a fixed time period. It should be noted that level 2 means graphic information, and other levels include level 1 indicating character information and level 3 indicating link information.

The data transmitted from the FM broadcasting station 5 has a transmission priority, and page data requiring real-time performance has a high priority and is transmitted at a time period of about 5 minutes. On the other hand, the macro data has a low priority and is transmitted at a time period of about 30 to 60 minutes. For this reason, the macro data is temporarily stored in the DRAM having a backup function so as to quickly respond to a display request of each screen.

[0010]

However, macro data has a large capacity, and there are many macro data corresponding to each of the above-mentioned sketch parts. Therefore, a memory capacity for storing them in a system construction becomes large. In addition, there is a problem that the ratio of the memory cost to the system cost increases.

In view of the above problems, it is an object of the present invention to temporarily store macro data as data that has been compressed using a predetermined data compression algorithm, and to store the compressed data when a display request is made. FM that reads out the data, converts it to image data, and outputs it to the display
It is an object of the present invention to provide a multiplex information processing apparatus and a method thereof.

[0012]

FIG. 1 is a block diagram showing an embodiment of the present invention.
FIG. 2 is a block diagram showing a basic configuration (1) of the M-multiplex information processing device. FIG. 2 is a block diagram showing another basic configuration (2) of the FM multiplex information processing apparatus according to the present invention. According to the present invention, as shown in FIG. 1, the information of the FM multiplex information section 10 having the FM multiplex information received from the FM multiplex broadcast is stored in the memory storage section 11, and the stored FM multiplex information is displayed on a display. FM displayed on unit 12
In the multiplex information processing apparatus, an FM multiplex information processing apparatus having a compression processing unit 100 that applies a predetermined data compression algorithm to the received FM multiplex information and stores data after compression processing in the memory storage unit 11 Is provided.

The compression processing section 100 includes a compression encoding section 102 for performing the compression processing, and further includes the received F
A preprocessing unit that determines the information type of the M-multiplexed information; and when the FM multiplexed information is macro data serving as a sketch of a display screen of simplified graphic information, the preprocessing unit 101 transmits the data. When the FM multiplexed information is page data that is overwritten data of the display screen in the simplified graphic information, the compression encoding unit 102 is bypassed 103.

According to the present invention, as shown in FIG. 2, the pre-processing unit 101 further includes a pre-processing unit for converting 8-bit data, which is an information unit of the received FM multiplex information, into 7-bit data. A processing operation unit 111;
An 8-7-bit conversion table 112 indicating the correspondence of each information unit between the bit data and the 7-bit data,
Then, the compression encoding unit 102 is provided with the pre-processing operation unit 11.
The information unit of 7-bit data given from 1 is compressed by Huffman coding.

Further, according to the present invention, there is provided an FM multiplex information processing method for receiving FM multiplex broadcasting and displaying simplified graphic information: converting the received simplified graphic information data into compressed data using a predetermined data compression algorithm. Storing; and in response to a predetermined screen display request, reading out and decompressing the corresponding compressed data, converting it into image data, and outputting the image data to a display device. .

[0016] As an aspect of the method, of the received simple graphic information data, only macro data serving as a sketch of a display screen is compressed. Before storing the data compressed using the predetermined data compression algorithm, the simplified graphic information data, which is data in units of 8 bits, is further converted into a 7-bit data using a predetermined 8-7 bit conversion table.
The data is converted into simple graphic information data in bit units, and the predetermined data compression algorithm is applied to the simple graphic information data in 7-bit units. Then, after the corresponding compressed data is read out and decompressed in response to the request for displaying the predetermined screen, the simple graphic information data in 8 bit units is further converted from the simple graphic information data in 7 bit units using the 8-7 bit conversion table. Restored, the restored 8
The simple graphic information data in bit units is converted into image data.

Further, according to the present invention, in addition to the above method, at the first receiving stage, it is determined whether the simplified graphic information data is macro data serving as a sketch of a display screen or page data serving as overwriting data thereof. Determining; if the received simple graphic information data is determined to be page data, storing the page data as it is; and if determining that the received simple graphic information data is macro data, Storing macro data as compressed data by Huffman coding; reading out the corresponding compressed macro data data according to a predetermined screen display request, decompressing the data by an inverse algorithm of Huffman coding, and storing the corresponding page data And convert them to image data, then superimpose them and output them to the display Rukoto; FM multiplex information processing method consisting is provided.

In one embodiment of this case, before storing the data compressed by the above-described Huffman coding, the simplified graphic information data, which is data in units of 8 bits, is further converted into a predetermined 8-7 bit conversion table. To convert the simple graphic information data into 7-bit simple graphic information, perform the Huffman encoding on the simple graphic information data in 7-bit units, and respond to the request for displaying the predetermined screen. After reading and decompressing,
Further, the simple graphic information data in the unit of 8 bits is restored from the simple graphic information data in the unit of 7 bits using the 8-7 bit conversion table, and the restored simple graphic information data in the unit of 8 bits is converted into image data. Converting is included.

[0019]

According to the present invention, the compression processing section 100 enables effective use and miniaturization of the memory storage section 11 by compressing FM multiplex information. At this time, the preprocessing unit 101 sorts the information type, and the macro data of the simplified graphic information having a large information capacity and a large data compression effect is compressed.
2, the remaining page data having a small information capacity is stored in the memory storage unit 11 as it is, bypassing the compression encoding unit 102 without performing compression processing.

Further, the pre-processing unit 101 uses the 8-7 bit conversion table to convert the simple graphic information data in units of 8 bits based on predetermined characteristics of the FM multiplex information.
It is converted into bit-by-bit simple graphic information data. As a result, the amount of information to be processed is significantly reduced, and the amount of data stored in the memory storage unit 11 is significantly reduced by performing the above-described compression processing on the simple graphic information data in units of 7 bits. .

[0021]

FIG. 3 is an apparatus block diagram showing an embodiment of an on-vehicle FM multiplex broadcast receiver provided with an FM multiplex information processing apparatus according to the present invention. Referring to the correspondence between FIG. 3 and FIGS. 1 and 2, the FM multiplex broadcast receiving unit 26 of FIG.
In the FM multiplex information section 10 and the TV receiving section 21 in FIG.
(4 inch LCD) correspond to the display means 12 of FIGS. 1 and 2, respectively. The CPU board 201 of the system controller 27 shown in FIG.
2 corresponds to the compression processing unit 100, and the memory board 202 of the system controller 27 in FIG. 3 corresponds to the memory storage unit 11 in FIG. 1 and FIG.

In FIG. 3, FM multiplex broadcast receiving section 26
Receives radio waves from FM multiplex broadcasting stations. AM / FM
The radio unit receives the FM broadcast as in the related art, and separates and decodes the data information from the received signal in the next-stage FM multiplex decoder. The decrypted data is stored in the memory board 202 of the system controller 27. The memory board 202 includes a data memory (DRAM) for temporarily storing the received data including character / vector data, an image memory (VRAM) for storing screen data including image data obtained by converting the stored data, And a table memory and the like managed under predetermined conditions.

The CPU board 201 of the system controller 27 converts, processes, and displays data between the data memory and the data stored in the image memory.
Further, it is composed of a CPU circuit for controlling the table memory for managing screen data and the like.
The information is sent to the 4-inch LCD display of the receiving unit 21 and displayed as, for example, a traffic information screen.

FIG. 3 shows a general configuration example of the receiving apparatus as a radio / optical beacon unit 23 to VICS for VICS.
25 and a TV receiver for receiving general television broadcasts. An operation remote controller 29 and audio units 30 to 34 are connected to the system controller 27. The former operates the keypad,
The latter provides various instructions to the system controller 27 and instructions such as selection of a received program by voice operation using voice recognition / synthesis technology.

FIG. 4 shows an example of the operation flow of the compression processing section 100 of FIG. As shown in FIG. 4, in step S101, the pre-processing unit 101 in FIG.
It is determined whether or not the received data is level 2 macro data having a large data capacity and a large compression effect. If the received data is determined to be level 2 macro data, the data is Huffman-coded by the compression coding unit 102 in FIG. 2 ( S102). if,
If the received data is data other than the level 2 macro data, the data compression / encoding processing is not performed (S10
3) The data as it is is written to the data memory (DRAM) of the memory storage unit 11 in the next stage.

In general, when compressing data of an audio or image signal, irreversible compression coding is performed with priority given to the compression efficiency due to the redundancy of the data. In order to guarantee accurate data reproducibility, Huffman coding is used, in which data compression / decompression is performed reversibly.

FIG. 5 shows a comparison example of the compression ratio when Huffman coding is applied to level 1 data (character information) and level 2 data (simple graphic information) in one page of page data or macro data. is there. As can be seen from FIG. 5, in the case of the level 1 data (100 bytes) and the level 2 page data (144 bytes) having a small data capacity, the data amount is conversely reduced to 139 bytes and 183 bytes by the Huffman coding. And increase (13
9% and 127%). On the other hand,
In the case of level 2 macro data (824 bytes) having a large data capacity, it can be seen that the data amount has been compressed to 605 bytes (73%) by Huffman coding.

FIG. 6 shows a comparative example of the compression ratio by Huffman coding for a plurality of level 2 macro data. FIG. 6 shows that the average of the compression ratio when the level 2 macro data is Huffman encoded is about 83%. For this reason, the compression processing unit 100 according to the present invention shown in FIG.
The significance of the data compression effect by selecting only macro data and performing Huffman coding on the data by the compression coding unit 102 is significant, and as a result, the data memory (DRAM) capacity of the memory storage unit 11 can be reduced.

When the data is converted into image data and displayed on the display unit 12, a demodulation unit comprising a CPU board 201 (not shown in FIG. 1) transfers the data to the data memory (DRAM). The stored received character / vector data is read for one screen, and the original received data is restored by performing an inverse Huffman encoding process, and the data is further converted and processed into screen data composed of image data and stored in a memory. The data is written to the image memory (VRAM) of the unit 11. The data written in the image memory is displayed on the display unit 12.

FIG. 7 shows an example of a control flow of the 8-7 bit conversion processing section 101 in the compression processing section 100 of FIG. This 8-7-bit conversion processing flow basically targets level 2 macro data selected by the pre-processing of FIG. 1 from the viewpoint of improvement in processing speed. However, it is also possible to perform the pre-processing after executing the present processing flow for all the received data, and to execute only the present processing flow without performing the pre-processing and directly encode it. Good.

In the following, level 2 after sorting by pre-processing is described.
Before describing the case where the macro data is subjected to 8-7-bit conversion processing, the characteristics of the received level 2 macro data will be described with reference to FIGS. FIGS. 8 to 10 respectively show occurrence distribution diagrams of data values in the 8-bit data values of the level 2 macro data file. FIG. 11 shows, for each of the files M202121 to M202126 shown in FIGS. 8 to 10, the number of 8-bit data values that do not exist in the file,
That is, the number of 8-bit data values whose occurrence number is "0" is shown for each file.

FIG. 11 shows that the number of occurrences of "0" in each of the level 2 macro data files M202121 to M202126 is 128 or more. Therefore, the number of data required to represent each level 2 macro data file is 128 or less, and
A file representation can be made with 7-bit data that can represent 128 data without using 8-bit data that can represent 6 data. The 8-7 bit conversion processing flow according to the present invention of FIG. 7 is performed from the above viewpoint.

Referring to FIG. 7, the received serial data is sequentially divided into data of one Ibat unit (8 bits) (S201), and the data generated in the macro data file is detected by detecting the data value of each byte. FF
The number of occurrences of each data value up to h is calculated (S20).
2). In step S203, a data value that does not exist in the macro data file (the number of data occurrences is "0")
Is calculated, and when it is 128 or more, it is determined that the 7-bit representation of the macro data file is possible.

In this case, a 7-8 bit conversion table 112 (see FIG. 2) indicating the correspondence when data is compressed from 8 bits to 7 bits in step S204 is created. The 7-8 bit conversion table 112 is referred to when restoring from 7 bits to 8 bits. Then, in step S205, the Huffman encoding process of the 7-bit data is performed in the Huffman encoding unit 102 in FIG. In step S203, the number of data values that do not exist in the macro data file (the number of “0”) is 127.
In the following cases, the 7-bit conversion process (S204) and the Huffman encoding process (S205) are bypassed (S206) because the 7-bit representation of the macro data file is impossible.

FIGS. 12 to 15 show examples in which the FM multiplex data “flat field wide area map” (file name: M202121) is actually converted from 8 bits to 7 bits. FIG.
Shows an example of the display screen of the “flat field wide area map”.
FIG. 13 shows the actually received data of FIG. FIG. 14 shows the number of occurrences of each data value in the macro data file of FIG. And FIG.
Shows an example of an 8-7-bit conversion table created from the results of FIG.

In FIG. 13, the number of occurrences of the 8-bit data value "00h" (shown by a rectangular frame in FIG. 13) represented by, for example, a hexadecimal number (h) is fourteen. Similarly, FIG. 14 shows each data value (d [0] to d [2
55]. ) Is obtained. For example, for the data value “00h” described above, d [
0] = 14 (pieces) (shown by a square frame in FIG. 14). Further, in the case of this example, the total number (C: count) of the data values with zero data occurrence is 149.

The 8-7 bit conversion table shown in FIG. 15 will be described. Here, the 8-bit data value is d256
[0] to d256 [255], and the 7-bit data value is d128 [0] to d128 [127]. In the 8-7 bit conversion table, d25
Among the data values of 6 [0] to d256 [255], those with zero occurrence are not assigned a 7-bit data value (in FIG. 15, there is no substantial d128 [xxx]). There.) Then, d256 [0] to d25
6 [255], if the number of occurrences is 1 or more, d128 [0] to d128 [0] which are sequentially 7-bit data values
d128 [127] is allocated. In the case of the data value "00h", d256 [0] = d1
28 [0]: (14) (indicated by a square frame in FIG. 15).

FIG. 16 shows an example of the mutual comparison between the compression ratio when the 8-bit data shown in FIG. 6 is Huffman coded and the compression ratio when the Huffman coding is performed after converting it into 7-bit data according to the present method. Is shown. Referring to FIG. 16, for example, the macro data file M202121 will be described. Its size is 824 bytes, and its 8-bit data size is 6592 (= 824 × 8) bits. When this is converted into 7 bits by the above-described method and then subjected to Huffman coding, the data size is 421
It becomes 0 bits, and a 63% improvement in compression ratio is seen.

FIG. 17 shows a comparison between the compression ratio of FIG. 6 and the compression ratio of FIG. From FIG. 17, it can be seen that the compression ratio is improved by 10 to 13% according to the present method as compared with the case where only 8-bit data is compressed.

[0040]

As described above, according to the present invention, the compression processing section compresses FM multiplexed information, thereby making it possible to effectively use the memory storage section and reduce its size. Further, according to the present invention, the information type is selected in the pre-processing unit, and only the macro data of the simplified graphic information having a large information capacity and having a large data compression effect is compressed, and the page data having a small information capacity is not subjected to the compression processing. Therefore, the data compression efficiency can be greatly improved.

Further, according to the present invention, the pre-processing unit converts the 8-bit simple graphic information data into a 7-bit simple graphic information data using an 8-7-bit conversion table based on a predetermined feature of the FM multiplex information. This reduces the amount of information to be processed by half. Further, the above-described compression processing is performed on the simple graphic information data in units of 7 bits, so that the speed of the compression processing and the required capacity of the memory storage unit are reduced. Achieved at the same time.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration (1) of an FM multiplex information processing apparatus according to the present invention.

FIG. 2 is a block diagram showing another basic configuration (2) of the FM multiplex information processing apparatus according to the present invention.

FIG. 3 is an apparatus block diagram showing one embodiment of an on-vehicle FM multiplex broadcast receiver provided with the FM multiplex information processing apparatus according to the present invention.

FIG. 4 is a flowchart showing an example of an operation flow of a compression processing unit in FIG. 1;

FIG. 5 is a diagram showing an example of a comparison of compression ratios when level 1 data and level 2 data constituting page data and macro data are Huffman-coded.

FIG. 6 is a diagram illustrating an example of a comparison of a compression ratio by Huffman coding for a plurality of level 2 macro data.

FIG. 7 is a flowchart illustrating an example of a control flow of an 8-7-bit conversion processing unit in the compression processing unit in FIG. 2;

FIG. 8 is a diagram illustrating an example (1) of the number of occurrences of each data value of an 8-bit data value included in a level 2 macro data file.

FIG. 9 is a diagram illustrating an example (2) of the number of occurrences of each data value of an 8-bit data value included in a level 2 macro data file.

FIG. 10 is a diagram illustrating an example (3) of the number of occurrences of each data value of an 8-bit data value included in a level 2 macro data file.

FIG. 11 is a diagram showing the number of 8-bit data values whose occurrence number is “0” in each of the files in FIGS. 8 to 10;

FIG. 12 is a diagram illustrating an example of a display screen of a “flat field wide area map”.

FIG. 13 is a diagram showing the reception data of FIG. 12;

FIG. 14 is a diagram showing the number of occurrences of each data value shown in FIG. 13;

FIG. 15 is a diagram showing an example of an 8-7-bit conversion table created from FIG. 14;

FIG. 16 is a diagram illustrating an example of mutual comparison of compression ratios when Huffman coding is performed on 8-bit data and when Huffman coding is performed after converting the data into 7-bit data.

FIG. 17 is a diagram showing a comparison between the compression ratio of FIG. 6 and the compression ratio of FIG. 16;

FIG. 18 is a diagram schematically illustrating a system configuration example of a VICS.

FIG. 19 is a diagram showing a principle configuration of a conventional FM multiplex information processing apparatus.

FIG. 20 is an explanatory diagram of a display method of FM multiplex information.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... FM multiplex information part 11 ... Memory storage part 12 ... Display display part 100 ... Compression processing part 101 ... Preprocessing part 102 ... Compression coding part 111 ... 8-7 bit conversion processing part 112 ... 8-7 bit conversion table

Continuation of front page (58) Fields investigated (Int.Cl. ⁷ , DB name) H03M 7/14 H03M 7/30 H03M 7/40 H04B 1/16 H04H 5/00 302

Claims (6)

(57) [Claims] 1. An FM multiplex information section having FM multiplex information received from an FM multiplex broadcast is stored in a memory storage section, and the stored FM multiplex information is displayed on a display section. In the FM multiplex information processing device, a predetermined data compression algorithm is applied to the received FM multiplex information, and the compression processing unit (11) stores the data after compression processing in the memory storage unit (11). 100) der
A compression encoding unit (102) for performing the compression processing;
Preprocessing for determining the information type of the received FM multiplex information
(101), wherein the pre-processing unit (101) includes a
A place for macro data to be a sketch of the display screen in shape information
In this case, the data is given to the compression encoding unit (102).
And the FM multiplex information is displayed in simplified graphic information.
In the case of page data that will be overwritten data on the screen,
The compression encoding unit (102) is bypassed (103).
FM multiplex information processing apparatus characterized by. 2. The pre-processing unit (101) further comprises: a pre-processing operation unit (111) for converting 8-bit data, which is an information unit of the received FM multiplex information, into 7-bit data ; An 8-7-bit conversion table (11) representing the correspondence of each information unit between 8-bit data and 7-bit data
2), and the compression encoding unit (102) is configured to execute the preprocessing operation unit (11).
The information unit of 7-bit data given from 1) to compression processing by Huffman coding, FM multiplex information processing apparatus according to claim 1. 3. An FM multiplex information processing method for receiving an FM multiplex broadcast and displaying simple graphic information, wherein the received simple graphic information data is a draft of a display screen.
Macro data or page data that will be overwritten data
The simple graphic information data received is determined to be page data.
In this case, the page data can be stored as is.
And the received simple graphic information data is determined to be macro data.
When, the macro data a predetermined algorithm
According to a predetermined screen display request, the corresponding compressed data is stored as compressed data.
Read and decompress and read the corresponding page data
An FM multiplex information processing method characterized by overwriting and outputting to a display . 4. Before storing data compressed using the predetermined data compression algorithm, the simplified graphic information data, which is data in units of 8 bits, is further stored in a predetermined 8 bits.
Converting the simple graphic information data in 7-bit units using the -7-bit conversion table, applying the predetermined data compression algorithm to the simple graphic information data in 7-bit units, After reading the corresponding compressed data and decompressing it according to the display request,
The method further includes restoring the simple graphic information data in units of 8 bits from the simple graphic information data in units of 7 bits using the 8-7 bit conversion table. The method according to claim 3 , wherein 5. An FM multiplex information processing method for receiving an FM multiplex broadcast and displaying simple graphic information, wherein the received simple graphic information data is macro data serving as a sketch of a display screen or overwriting data thereof. Determining whether the received simple graphic information data is page data, if the received simple graphic information data is determined to be page data, storing the page data as it is, determining that the received simple graphic information data is macro data In this case, the macro data is stored as data compressed by Huffman coding, and the corresponding compressed macro data data is read out according to a predetermined screen display request and decompressed by an inverse algorithm of Huffman coding. And read the corresponding page data, convert them to image data, An FM multiplex information processing method comprising superimposing and outputting to a display. 6. Before storing the data compressed by the Huffman coding, the simplified graphic information data, which is 8-bit data, is further converted into 7-bit simplified data using a predetermined 8-7-bit conversion table. Converting the graphic data into graphic information data, performing the Huffman encoding on the simplified graphic information data in units of 7 bits, and reading and decompressing the corresponding compressed macro data in response to the display request of the predetermined screen. After that, the above-mentioned 8-
Converting the 8-bit simple graphic information data from the 7-bit simple graphic information data using a 7-bit conversion table, and converting the restored 8-bit simple graphic information data into image data Claims
5. The method according to 5 .