JPH07306854A - Method and device for compressing document data - Google Patents

Abstract

PURPOSE:To effectively utilize a memory by decreasing the amount of document data which are previously generated as a document to be displayed. CONSTITUTION:A control part 1 calculates words included in a document inputted from an input device 2 and the frequencies of appearance of the words. Codes different from codes assigned to character data are assigned to the respective words, and the 1st total number W1 of words (= the number Nw of words Xfrequency Ni of appearance) and the 2nd total number W2 of words (= the number Nc of words of codes X frequency Ni of appearance + the number Nw of words) are calculated, word by word. Then parts constituting words whose 2nd total number W2 of words are less than the 1st total number W1 of words in the character data constituting the input document are replaced with the codes assigned to the respective words concerned to compress the document data. The words which become small in the total number of words in the whole document are replaced with the codes indicating the words concerned to decrease the amount of the document data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document data compression method and apparatus for compressing document data such as comments and messages prepared in advance for display on a display device such as a liquid crystal display and storing it in a memory. It is a thing.

[0002]

2. Description of the Related Art Conventionally, in office machines such as facsimiles and copiers, various industrial machines, and the like, document data such as various operating methods and comments have been created in advance so that they can be used for operating states of machines and key operations by operators. Accordingly, a display technique is known in which appropriate document data is selected and displayed on a display.

In such a display technique, a display document prepared in advance is converted into data in units of characters by coded characters, numbers or other symbols at the time of manufacturing office equipment such as the above-mentioned facsimile and copying machine. The document data is stored in the internal memory built in the office equipment body together with the code table for converting the document data.

When displaying the document data, the document data to be displayed is read out from the internal memory, and each character is converted into code data (7 bits or 8 bits) using the above code table.
After conversion into bit data), a method of driving a display device such as a liquid crystal display based on the code data is adopted.

FIG. 4 is a diagram showing an example of document data stored in a conventional internal memory. In the figure, “display document” is a document displayed on the liquid crystal display, and examples of the document include “LINE TYPE” and “SET LINE”.
"TYPE" is posted. Also, "Document data"
Is the data structure of the display document stored in the internal memory. The document data is composed of an array of characters, numbers or other symbols (hereinafter referred to as character data) assigned to each code data in the JIS code table, for example. Each character data is separated by ",", blank data (represented by "□" in the figure) between words, and end data indicating the end of document (represented by "0" in the figure) between documents. ) Are separated from each other.

In the display control of the above-mentioned display document, the document data to be displayed is read out from the internal memory, each character data is converted into code data by, for example, the JIS code table, and then the liquid crystal display is based on this code data. The document is displayed by driving. For example, when displaying "LINE TYPE", character data of "L", "I", ...
Each character data that is read out is code data ('
L '=' 00111100 ',' I '=' 100111
00 "). Then, by controlling the drive of the display segment provided in the liquid crystal display based on the code data, "LINE TYPE"
Is displayed.

[0007]

Conventionally, each character forming a display document is converted into character data to create document data of the display document, and this document data is stored in an internal memory. Since the amount of document data is large and the area of the document data in the storage area of the internal memory is large, it is difficult to effectively use the internal memory. In particular, when the same word having a large number of characters is used many times in the display document, the number of characters included in the entire display document is large even for a display document having a small number of words, and thus the amount of document data is large. .

Further, in office equipment exported to a plurality of foreign countries, in order to avoid the trouble of providing a display document in the language of the country and a dedicated code table for converting code data for each exporting country, In many cases, the character data that can be used for display documents and the code table for converting this character data into code data are commonly used. In this case, however, a dictionary of 10 languages is usually required. The amount of data in the table becomes huge, which hinders effective use of the internal memory.

Further, in the conventional display system for converting a display document into code data on a character-by-character basis, it takes time to search a code table (that is, to convert each character data into code data), and to display it on a liquid crystal display or the like. There is also the problem of poor display response.

An object of the present invention has been made in view of the above problems, and it is possible to reduce the amount of document data as much as possible to improve the efficiency of the memory and to improve the display response. An object of the present invention is to provide a method of compressing document data and a device thereof.

[0011]

According to a first aspect of the present invention, a plurality of document data created in advance by character data defined by a predetermined code table is used, and a part of words included in the document data is converted. A method for compressing document data that is compressed by encoding in word units, comprising a word extraction step of extracting words to be encoded in word units from words included in all document data, and the above-mentioned code for each extracted word. A code allocating step of allocating a code different from the code assigned to the above character data in the table, and a dictionary creating step of creating a dictionary showing the correspondence between the coded word and the code assigned to the word Among the words that compose the document data, replace the word extracted in the word extraction step with the code assigned to the word, and mix each document data with the code. It is made of the document data compression step of compressing the document data.

According to a second aspect of the present invention, in the method of compressing document data described above, instead of the document data compression step, a word number calculation step of calculating the number of words coded for each document data, For each document data, of the words that compose the document data, replace the word extracted in the word extraction step with the code assigned to the word, and code the number of words at the beginning of each document data. And a document data creating step for creating compressed document data.

According to a third aspect of the present invention, in the method of compressing document data, the word extracting step includes a first word extracting step of extracting words having different character strings included in all document data, and an extracting step. For each word, the word expression number counting step of counting the expression number in all document data, and for each extracted word, the first total word number required for the word when encoded in character units A first total word number calculation step of calculating based on the number of occurrences, and for each extracted word, a second total number of words required for the word when encoded in word units, based on the number of occurrences of the word Comparing the second total word number calculation step for calculation with the first total word number and the second total word number,
A second word extracting step of extracting a word having a second total number of words smaller than the first total number of words as a word to be encoded.

Further, in the invention of claim 4, in the method of compressing document data, the first total word number calculating step multiplies the word number of each extracted word by the expression number. The first total word number is calculated, and in the second total word number calculation step, for each extracted word, the expression number of the word is multiplied by the number of words of the allocated code, and the multiplication result is obtained. To calculate the second total number of words.

Further, according to the invention of claim 5, the document data composed of a plurality of documents created in advance by the character data defined by a predetermined code table is used, and a part of the words included in the document data is used as a word unit. A device for compressing document data that is compressed by being coded by and stored in a storage unit, and is a word extraction unit that extracts words to be encoded in word units from words included in all document data, and each extracted word. In addition, a code allocation means for allocating a code different from the code assigned to the character data in the above code table and a dictionary showing the correspondence between the coded word and the code assigned to the word are created. The dictionary creating means and the words constituting the document data are extracted by replacing the words extracted in the word extracting step with codes assigned to the words. And document data compressing means for compressing the data in the document data code mingled, in which a data writing means for writing the compressed document data and created dictionary storage means.

According to a sixth aspect of the present invention, in the document data compression device, the document data compression means is replaced by
A word number calculation means for calculating the number of words coded for each document data, and for each document data, the words extracted by the word extraction means among the words constituting the document data are assigned to the word. And a document data creating means for creating compressed document data by adding data of the coded word number to the beginning of each document data.

According to a seventh aspect of the present invention, in the document data compression apparatus, the word extracting means includes first word extracting means for extracting words having different character strings contained in the document data. For each word, word expression number counting means for counting the number of occurrences in the document data, and for each extracted word, the first total number of words required for the word when encoded in character units is the expression number of the word. And a first total word number calculating means for calculating each word, and for each extracted word, a second total number of words required for the word when coded in word units is calculated based on the number of occurrences of the word. The second total word number calculating means is compared with the first total word number and the second total word number, and a word having a second total word number smaller than the first total word number is determined as a word to be coded. Extraction To is made of a second word extraction means.

Further, in the document data compressing apparatus according to the present invention, the first total word number calculating means multiplies the number of words of each extracted word by the expression number. A second total word number calculating means calculates a first total word number, and for each extracted word, the number of occurrences of the word is multiplied by the number of allocated code words, and the multiplication result is obtained. To calculate the second total number of words.

[0019]

According to the invention described in claims 1 and 5, words to be coded in word units are extracted from the words included in the document data, and each extracted word is a code of the code table and the character data. A code different from the code assigned to is assigned. Next, a dictionary showing the correspondence between the coded words and the codes assigned to the words is created, and the words extracted as the words to be coded among the words forming the document data are set to the words. The document data is replaced with the assigned code, and the document data is compressed into the document data containing the code. Then, the created document data and dictionary are written in the storage means.

According to the second and sixth aspects of the present invention, the number of words coded for each document data is calculated, and the word to be coded among the words constituting the document data is calculated for each document data. The word data extracted as is replaced with the code assigned to the word, and the data of the number of coded words is added to the head of each document data to create compressed document data.

According to the third and seventh aspects of the invention, words having different character strings contained in the document data are extracted, and the number of occurrences (Ni) in the document data is counted for each extracted word. . Then, for each extracted word, the first total word number (W1) required for the word when encoded in character units is calculated based on the number of occurrences (Ni) of the counted word, and The second total number of words (W2) required for the word when coded in word units is calculated based on the counted number of occurrences (Ni) of the word, and further the first total number of words (W1). And the second total number of words (W2) are compared,
A word having a total number of words (W2) smaller than the first total number of words (W1) is extracted as a word to be encoded.

According to the fourth and eighth aspects of the present invention, for each extracted word, the first total word number (W1 = Nw) is obtained by multiplying the word number (Nw) with the word by the expression number (Ni).
XNi) is calculated, the number of occurrences (Ni) of the word is multiplied by the number of words (Nc) of the code to be assigned, and the multiplication result (Nc × Ni) is added with the number of words (Nw) of the word. The second total number of words (W2 = Nc × Ni + Nw) is calculated.

[0023]

1 is a block diagram of a document data compression apparatus to which a method for compressing document data according to the present invention is applied. In a device such as a facsimile or a copying machine equipped with a display device such as an LCD (Liquid Cyristal Display), a predetermined document such as a comment or a message is usually prepared according to the operation state of the device or an operator's key operation. Are displayed on the display device. The display of such a document is performed by a ROM in which data representing the plurality of documents (hereinafter, document data) is built in the device.
It is written in advance in a memory such as (Read Only Memory), and reads out predetermined document data from the memory according to the operation state of the device or the key operation of the operator, and drives the LCD based on the document data. It is supposed to be done.

The document data compression apparatus shown in FIG. 1 compresses the document data created by the operator and writes it in the memory built in the device.

The document data compression device comprises a compression device 1, an input device 2, a display device 3, and a data writing device 4. The memory 5 is a memory including a ROM or the like in which document data (compressed data) created by the document data compression device is stored, and is built in a device such as a facsimile or a copying machine. In addition to the document data and the dictionary, the memory 5 also stores various data and processing programs necessary for controlling the operation of the device.

The input device 2 is an operating member for an operator to input the above-mentioned document, and is provided with keys, ten keys, and function keys for inputting characters, numbers and various symbols. The document is input by the input device 2 character by character. The characters, numbers, symbols and functions assigned to the respective keys of the input device 2 are defined by JIS code table, AS
Correspondence with the code data is defined by a predetermined code table such as a CII code table, and each character input by key operation is converted into predetermined code data based on the above code table, and the compressed data is stored in the compression device 1. Is entered.

The display device 3 is a CRT (Cathode Ray Tub).
e), which is composed of an LCD or the like, and provides a display necessary for creating and compressing document data described later.
For example, the document input from the input device 2 is displayed on the display device 3, and the display allows the operator to confirm, correct, delete, etc. the input character.

The compression device 1 is a device that compresses the document data input from the input device 2 and creates the document data to be written in the memory 5. The compression device 1 includes a data input unit 11, a document memory 12, a word expression number counter 13 (first word extraction unit, word expression number counting unit), a code allocation unit 14 (code allocation unit), and a total word number calculation unit 15.
(First and second total word number calculation means), compressed word extraction unit 16 (word number calculation unit, second word extraction unit), document data compression unit 17 (compressed document data creation unit, dictionary creation unit) ) And a control unit 18.

The word expression number counter 13, the total word number calculation unit 15, and the compressed word extraction unit 16 constitute word extraction means for extracting words to be coded in word units from the words included in all document data. ing.

The data input unit 11 is an interface unit for taking in the document data input from the input device 2 into the compression device 1. The input document data is
The input document is output to the display device 3, the input document is displayed on the display device 3, and is temporarily stored in the document memory 12.

The document memory 12 stores the document data input from the input device 2 for the data compression processing described later. The word expression number counter 13 extracts independent words (words having different character strings) contained in the input document, and counts the expression number Ni of each word in the entire document.

The code allocator 14 adds to the extracted words
The code of the area that is not assigned to the characters in the above code table is assigned.

For example, if the characters and the like are defined by the JIS code table shown in Table 1, the code of the area that is not assigned to the characters and the like in the JIS code table, for example, "0 (row) x 00 (column)" ~ "15 (line) ~ 00
(Column) "," 0 (row) x 01 (column) "-" 15 (row)-"
The code assigned to the functional character "00 (column)" or "0 (row) x 08 (column)" to "15 (row) to 08
(Column) "," 0 (row) x 09 (column) "~" 15 (row) ~ "
An undefined code such as "09 (column)" is assigned to the extracted word.

[0034]

[Table 1]

For each word extracted, the total word number calculation unit 15 is the word number (byte number) N that constitutes the word.
The first total word number W1 (= Ni × Nw) obtained by multiplying w by the expression number Ni of the word, and the word number (byte number) Nc of the allocated code are multiplied by the expression number Ni of the word, A second total word number W2 (= Nc) obtained by adding the word number Nw of the word to the multiplication result (Nc × Ni)
XNi + Nw) is calculated.

The first total number of words W1 is the amount of data (the number of bytes) required for the word in the uncompressed document data, and is the total number of words required for the word when coded in character units. Also, the second total number of words W2
Is the compressed document data (the document data when the document data is compressed by replacing the word with the assigned code)
Is the total amount of data (bytes) required for the word, and is the total number of words required for the word when coded in word units.

The compressed word extraction unit 16 extracts a word to be coded from the extracted words. That is, the document data compression method according to the present invention compresses the data amount of all document data by replacing a part of words included in the document data with a code on a word-by-word basis. The unit 16 extracts a word to be coded, that is, a word to be replaced with a code on a word-by-word basis.

The compressed word extraction unit 16 extracts a word whose second total word number W2 is smaller than the first total word number W1 as a word to be compressed. This is the second total word count W2
This is because the data amount of the word in the document data is reduced by replacing the word with the assigned code when the word is smaller than the first total word number W1.

Further, the compressed word extraction unit 16 calculates the number of encoded words for each document data. The data of the number of words is added to the head of the document data in the compression process of each document data.

The document data compression section 17 compresses the document data and creates a dictionary showing the correspondence between the words extracted for compression and the assigned codes. The document data compression unit 17 includes, for each document data, the compressed word extraction unit 16 among the words constituting the document data.
The word extracted in step (3) is replaced with the code assigned to the word, and the data of the number of words is added to the head to compress the document data.

The control unit 18 centrally controls the compression process of document data described later. The control unit 18 controls the operation of each unit of the data input unit 11 to the document data compression unit 17 to perform the compression process of the document data. The data writing device 4 writes the document data and the dictionary compressed by the compression device 1 into the memory 5.

Next, the document data compression processing of the document data compression apparatus will be described with reference to the flowchart of FIG.

In this embodiment, "LINE TYPE
Specific processing will be described with reference to two document data examples of "E" and "SET LINE TYPE". In addition, the character data forming the document is defined by the JIS code table.

First, the input device 2 is used to display "LINE TY
When a document of "PE" and "SET LINE TYPE" is input, this document is temporarily stored in the document memory 12 in the compression device 1 in the document data format shown in FIG. 4 (S1).

Then, when the input of the document data is completed,
The word "LIN" having different character strings included in the document data
“E”, “SET”, and “TYPE” are extracted, and the number of extractions K = 3 of each word is counted by the counter 12 (S2). Note that each word is blank data '
Since it is sandwiched by □ 'or end data' 0 ', it is detected by distinguishing them. In addition, only the words having different character strings are extracted by comparing the detected words with the already extracted words.

Then, a code different from the code assigned to the character data forming the word is assigned to each extracted word (S3). That is, the code of the area that is not used as the code of the character data of the JIS code table is assigned to each word. For example, "SET", "LI
"0x00" and "0x0" assigned to the function characters of the JIS code table are assigned to the words "NE" and "TYPE", respectively.
Codes of "1" and "0x02" are assigned respectively.

Next, the number of occurrences Ni (times) in the document data is counted by the word occurrence number counter 13 for each extracted word (S4). In the above example, the expression numbers Ni of the words “LINE”, “SET” and “TYPE” are “2”, “1” and “2”, respectively.

Then, for each extracted word, the first
The total number of words W1 (= Ni × Nw) (bytes) is calculated (S5). In the above example, the words "LINE", "SE
Since the word numbers Nw (bytes) of “T” and “TYPE” are “4”, “3”, and “4”, respectively, the first total word number W1 is “8 (= 2 × 4)”. , "3 (=
1 × 3) ”and“ 8 (= 2 × 4) ”.

Then, for each extracted word, the second
The total number of words W2 (= Ni × Nc + Nw) (bytes) is calculated (S6). In the above example, the number of words Nc (bytes) of the assigned codes “0x00”, “0x01”, and “0x02” is “1”, so the word “LI
The second total word numbers W2 of “NE”, “SET”, and “TYPE” are “6 (= 1 × 2 + 4)” and “4 (= 1
“× 1 + 3)” and “6 (= 1 × 2 + 4)”.

Then, a word whose second total word number W2 is smaller than the first total word number W1 is extracted as a word to be coded (S7). In the above example, the second total word number W2
Is less than the first total word count W1
Since these are "E" and "TYPE", these words are extracted.

The number of words to be coded is calculated for each document data (S8). In the above example, "LINE
The number of words “2” is calculated for each document data of “TYPE” and “SET LINE TYPE”.

Then, as shown in Table 2, a dictionary showing the correspondence between the word to be coded and the code assigned to this word is created (S9), and the document data is further compressed (S10). .

[0053]

[Table 2]

FIG. 3 is a diagram showing an example of compressed document data. In the figure, the head data "0xFB" of each document data is the data of the number of words for the document data. "0xFB" indicates the number of words "2",
"LINE TYPE" and "SET LINE TY"
Of the words that compose each document data of "PE", two words (LINE, TYPE) are code (0x01, 0
X02).

As described above, the data of the number of words replaced by the code is added to the beginning of each document, when the document data is displayed, all the coded words are converted into code data. For facilitating confirmation of completion and simplifying conversion processing of each document data into code data. In other words, if the number of words that have been replaced with codes is known in advance, if the number of words converted into code data by the dictionary by the dictionary reaches the number in the conversion process of each document into code data, After that, it is only necessary to convert the code data into character data using the JIS code table, and it is not necessary to use the dictionary and the JIS code table separately to convert the code data, which simplifies the conversion process. Then, this can also improve the display response.

Since the second total word number W2 is larger than the first total word number W1, the word "SET" is represented by character data without being replaced by a code. When a word is replaced with a code, the code indicates one word, and therefore blank data “□” for identifying the word is not provided before and after the code.

When the compression process of the document data is completed, the document data and the created dictionary are written in the memory 5 (S11), and the compression process of the document data is completed.

In the above embodiment, the codes are assigned to all the words before the words to be coded are extracted. However, when the number of assigned words is predetermined, the words to be coded are selected. After extraction, a code may be assigned to the word. in this case,
In FIG. 2, the process of S3 is performed between S7 and S8 or S8.
Between S9 and S9.

In a device such as a facsimile or a copying machine, the compressed document data is L
It is displayed on a display device such as a CD.

That is, for example, "SET LINE T
When displaying a document of “YPE” on the LCD, “0 × FB, 'S', 'E', 'T', 0 × 01, 0 × is read from the memory 5.
The document data of "02, '0'" are sequentially read,
Character data of "S", "E" and "T" are coded as "3x05" and "5x0" according to the JIS code table, respectively.
LCD converted to code data of 4 "and 4x05"
Is output to. Also, the codes "0x01" and "0x0"
2 ”is the word“ LIN ”according to the dictionary in the memory 5.
Code data strings ('L', 'I', 'N', 'E', 'T', 'of the character data forming "E" and "TYPE"
Y ',' P ',' E ') are collectively converted and output to the LCD. Then, by controlling the driving of the LCD based on the code data, the "SET LINE T
The document "YPE" is displayed.

As described above, the document data is a word in which the second total word number W2 is smaller than the first total word number W1 among the words included in the document data, that is, the word in the entire document data. Since only words that have a smaller number of words than when treated with only character data are replaced with the codes assigned to the words and compressed, the data is compared to conventional document data that consists of only character data. The quantity is reduced. As a result, the capacity ratio of the document data in the memory 5 decreases, and the memory 5 can be effectively used.

The above example will be described in detail.
If a document of "INE TYPE" is composed only of character data, as shown in FIG. 4, the number of words is "10", and the amount of data is 10 bytes. As shown in, the number of words becomes data of "4", and the data amount is reduced to 4 bytes.

Similarly, "SET LINE TYPE"
In the case of the above document, the data amount is 14 bytes if it is composed of only the character data, but the data amount is reduced to 7 bytes if it is composed of the character data and the code. Therefore, in the entire document, when the document data is composed of the character data and the code, the data amount can be reduced by 13 bytes as compared with the case where it is composed of only the character data.

When the document data is composed of word number data, character data and codes, a dictionary showing the correspondence between words and codes is required in addition to the JIS code table, and the capacity of the memory 5 is increased accordingly. Although it will be consumed, since the dictionary data increase amount can be absorbed by the above-described document data compression effect, the capacity ratio of the document data and the dictionary in the memory 5 can be made smaller than the capacity ratio of the conventional document data. .

Also, in the document data display process, the words replaced with the code are collectively converted into code data in word units, so that the document data is converted into code data in character units in a quicker process than in the conventional example. It is possible to improve the response performance of the display.

The document data compression device may be incorporated in an office machine such as a facsimile or a copy machine so that the office machine body has a document data compression function. In this case, the operation panel and the display device provided in the office equipment body serve as the input device 2 and the display device 3, respectively. Further, the office equipment main body is made to be able to set the document data compression mode, and when the document data compression mode is set, the control unit of the office equipment main body executes the flowchart shown in FIG. Performs document data compression processing.

When the office device body is provided with the document data compression function in this way, the document data can be changed, added, and deleted according to the user's request not only at the time of manufacturing the office device but also after the product is shipped. Therefore, the convenience of office equipment is improved.

[0068]

As described above, according to the present invention,
A plurality of document data created in advance using document data defined by a predetermined code table, some words included in all document data are codes in the code table, and codes assigned to the character data. Since it is replaced with a code different from the above and compressed into the document data with the mixed code, the data amount of the document data can be reduced. Thereby, the capacity ratio of the document data in the storage means can be reduced, and the utilization efficiency of the storage means is improved.

Further, when each document data is displayed on the display device or the like, the coded words are collectively converted into code data on a word-by-word basis based on the dictionary, so that the conversion process of document data to code data can be performed quickly. The display response of the document data is improved.

At the beginning of each compressed document data,
Since the data of the coded word number included in the data is added, it is possible to easily confirm the completion of the conversion of all the coded words to the code data, and the conversion when converting each document data to the code data. Processing is easy.

Of the words included in the document data,
If the second total number of words required for the word when encoded in word units is smaller than the first total number of words required for the word when encoded in character unit, only the relevant word is allocated. Since the document data is compressed by substituting the code, the document data with high compression efficiency can be obtained.

For each extracted word, the first word count is calculated by multiplying the word count of the word by the expression count, multiplying the first word count by the expression count of the word, and Since the word number of the word is added to the multiplication result to calculate the second total word number, it is possible to easily calculate the first word number and the second word number.

[Brief description of drawings]

FIG. 1 is a block diagram of a document data compression apparatus according to the present invention.

FIG. 2 is a flowchart showing a document data compression process of the document data compression apparatus according to the present invention.

FIG. 3 is a diagram showing an example of document data compressed by a document data creation device according to the present invention.

FIG. 4 is a diagram showing an example of conventional document data.

[Explanation of symbols]

 1 Compressor 11 Data Input Unit 12 Document Memory 13 Word Expression Number Counter 14 Code Allocation Unit 15 Total Word Number Calculation Unit 16 Compressed Word Extraction Unit 17 Document Data Compression Unit 18 Control Unit 2 Input Device 3 Display Device 4 Data Writing Device 5 memory

Claims (8)

[Claims] 1. A document data for compressing a plurality of document data created in advance by character data defined by a predetermined code table by encoding a part of words included in the document data in word units. A compression method, a word extraction step of extracting words to be coded in word units from words included in all document data, and each extracted word is assigned to the character data which is the code in the above code table. A code allocation step of allocating a code different from the code, and a dictionary creation step of creating a dictionary showing a correspondence relationship between the coded word and the code allocated to the word,
Of the words constituting the document data, the word extracted in the word extracting step is replaced with the code assigned to the word, and the document data compressing step of compressing each document data into the document data containing the code. Characteristic document data compression method. 2. The method of compressing document data according to claim 1, further comprising a word number calculating step of calculating the number of words coded for each document data, instead of the document data compressing step.
For each document data, among the words that compose the document data, replace the word extracted in the word extraction step with the code assigned to the word, and set the number of words coded at the beginning of each document data. A method for compressing document data, comprising: a document data creating step of creating compressed document data by adding data. 3. The method of compressing document data according to claim 1, wherein the word extracting step includes a first word extracting step of extracting words having different character strings included in all document data, and each extracted word. For a word, the word expression number counting step of counting the number of occurrences in all document data, and for each extracted word, the first total number of words required for the word when encoded in character units is the expression number of the word. And a second total word number calculation step for calculating each word extracted for each word, based on the number of occurrences of the word. The second total word number calculation step is compared with the first total word number and the second total word number, and a word whose second total word number is smaller than the first total word number is determined as a word to be coded. First to extract 2. A method for compressing document data, which comprises two word extraction steps. 4. The method for compressing document data according to claim 3, wherein in the first total word number calculating step, for each extracted word, the word number of the word is multiplied by the expression number to obtain a first total word number. The number of words is calculated, and in the second total word number calculation step, for each extracted word, the number of occurrences of the word is multiplied by the number of words of the allocated code, and the multiplication result of the word is calculated. Second by adding the number of words
A method for compressing document data, characterized in that the total number of words in is calculated. 5. Document data composed of a plurality of documents created in advance by character data defined by a predetermined code table is compressed by encoding some words included in the document data in word units. A device for compressing document data to be stored in a storage unit, a word extracting unit for extracting a word to be coded on a word-by-word basis from words included in all document data, and a code in the above code table for each extracted word. There is a code allocating means for allocating a code different from the code assigned to the character data, a dictionary creating means for creating a dictionary showing the correspondence between the coded word and the code assigned to the word, and the document data. Of the words that make up the document, replace the words extracted in the word extraction step with the codes assigned to the words, and replace each document data with the document data containing the codes. An apparatus for compressing document data, comprising: a document data compressing unit for compressing the compressed document data and a data writing unit for writing the compressed document data and the created dictionary in a storage unit. 6. The document data compression apparatus according to claim 5, wherein instead of the document data compression means, a word number calculation means for calculating the number of words coded for each document data, and for each document data, Of the words forming the document data, the words extracted by the word extracting means are replaced with the codes assigned to the words, and the data of the coded word number is added to the head of each document data and compressed. And a document data creating means for creating the document data. 7. The apparatus for compressing document data according to claim 5, wherein the word extracting means includes first word extracting means for extracting words having different character strings contained in the document data, and each extracted word. With respect to the word expression number counting means for counting the expression number in the document data, and for each extracted word, the first total number of words required for the word when encoded in character units is based on the expression number of the word. And a second total word number calculating means for calculating each word extracted, and a second total word number required for the extracted word when the word is encoded on a word-by-word basis based on the number of occurrences of the word. Of the total word number and the first total word number and the second total word number are compared, and a word having a second total word number smaller than the first total word number is extracted as a word to be coded. Second A document data compression apparatus comprising: a word extraction unit. 8. The document data compression apparatus according to claim 7, wherein the first total word number calculation means multiplies the word number of each extracted word by the expression number to obtain a first total word number. The second total word number calculating means calculates the number of words, and for each extracted word, the number of occurrences of the word is multiplied by the number of words of the assigned code, and the multiplication result of the word is multiplied. Second by adding the number of words
An apparatus for compressing document data, characterized in that it calculates the total number of words in.