JPH04180469A - Code extending method and plotting device - Google Patents

Abstract

PURPOSE:To shorten plotting processing time and to reduce a memory capacity by determining a Modified Huffman(MH) code extending table and a plotting color, extracting an arbitrary MH code word from among MH code data and converting the extracted code word into a non-compressed code by referring to the MH code extending table. CONSTITUTION:The constitution of a plotting device 2 is separated into a character developing and processing part 2a, a graphic developing and processing part 2b and a picture developing and processing part 2c to execute corresponding processing by respective data classifications such as character data 1a, graphic data 1b, picture data 1c transferred from a computer 1. A picture data control processing part 2c1 executes the setting of the plotting attribute of the picture data. An MH code extending processing part 2c2 executes elongating processing from an MH code word which is a compressed word to a non- compressed code. A clip processing part 2c3 executes the monitoring of a plotting area. A plotting processing part 2c4 executes the plotting of the non- compressed code. An offline data processing part 2c5 executes the linear density conversion of the picture data of offline plotting.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is directed to an MH code (Modified Code) which is a compression code.
The present invention relates to a compressed code decompression method and a drawing device for converting a utlvxn code (defined by CCITT recommendation, standardization of group facsimile devices for document transmission) into an uncompressed code and performing drawing processing.

(Prior Art) Conventional drawing devices use uncompressed codes for image data to be drawn. In drawing processing, the code or data itself is image data, and the drawing color is determined depending on whether the bit is "0" or "1", and by performing drawing processing for the number of codes themselves, the image data is drawn. was doing.

(Problems to be Solved by the Invention) The conventional drawing device described above does not take into consideration the drawing processing time and memory capacity when the amount of image data to be drawn increases, and when the amount of image data increases. However, there is a problem in that the drawing processing time and memory amount increase in proportion to the amount of image data.

The present invention solves such problems, and the invention of claim 1 aims to shorten the drawing processing time of image data and reduce the memory capacity when the amount of image data to be drawn increases. The invention according to claim 2 is characterized in that it provides a compressed code decompression method capable of converting a compressed code into an uncompressed code by performing fixed extraction of an MH code word once from MH code data. The invention as claimed in claim 3 is characterized in that it provides an MH code decompression method that allows the MH code word to be extracted A times from the MH code data. By extracting, codes can be extracted until the relationship of code length ≧ extraction bits is satisfied, and M
The invention according to claim 4 is characterized in that it provides an MH code expansion method capable of reducing the capacity of an H code expansion table. According to claim 5, there is provided an MH code decompression method capable of reducing the capacity of the MH code decompression table and shortening the decompression processing time by making the number of bits extracted based on the sort information variable length. SUMMARY OF THE INVENTION An object of the invention is to provide a drawing device that can reduce the capacity of an MH code expansion table and increase the speed of MH code expansion.

(Means for Solving the Problem) In order to achieve the above object, the invention of claim 1 converts an MH code word into an uncompressed code by referring to an MH code expansion table corresponding to each MH code word. This is an MH code expansion method.

In order to achieve the above object, the invention of claim 2 uses a fixed extraction method to extract from MH code data so that one or more MH code words are always included in one extraction, and the extracted MH By referring to the MH code expansion table for the code word once,
This is an MH code expansion method that converts into an uncompressed code.

In order to achieve the above object, the invention of claim 3 performs extraction from the MH code data using a divided extraction method A times (A=1.2.3...), and for each extraction, This MH code expansion method refers to an MH code expansion table and, when one or more MH code words are extracted, converts the extracted MH code words into uncompressed codes.

In order to achieve the above-mentioned object, the invention of claim 4 includes B (B=1°2.3...) containing an MH code word to be arbitrarily extracted from MH code data by a variable extraction method.
The number of bits extracted according to the bit information of the bit is set as variable length, and the MH code word of the extracted variable length bit number is M
M to convert to uncompressed code by referring to H code expansion table
This is an H code decompression method.

In order to achieve the above object, the invention of claim 5 includes a means for determining an MH code expansion table and a drawing color, a means for extracting an arbitrary MH code word from MH code data, and a means for extracting an arbitrary MH code word from the MH code data. The present invention is a drawing device that includes means for converting a MH code word into an uncompressed code by referring to an MH code expansion table.

(Function) The invention of claim 1 converts the MH codeword, which is a compressed code, into an uncompressed code. The number of uncompressed codes corresponding to By adding and referencing the MH code expansion address corresponding to the MH code word,
It is possible to know the code length of the actual MH code word of the conversion of the MH code extracted this time and the drawing amount that has been non-compressed encoded.

In the invention of claim 2, by setting the number of bits of the MH code word extracted by one fixed extraction method to a predetermined bit number, one or more MH code words always exist in one extraction. The extracted MH code word is converted into an uncompressed code by referring to the MH code word expansion table once.

In the invention of claim 3, the divided extraction method is adopted A times, and by dividing the number of bits to be extracted for each extraction of the MH code word, the MH code word of the divided number of bits is subjected to MH code decompression. By referring to the table and converting it into an uncompressed code, MH codewords whose code length is smaller than the number of bits resulting from the division can be expanded by initial division, and the capacity of the MH code expansion table is can be reduced.

In the invention of claim 4, in the variable extraction method in which the number of bits to be extracted is varied according to the bit information of B bits including the MH code word to be arbitrarily extracted from the MH code data, The number of bits to be extracted is variable for each group, and the number of bits to be extracted is variable for each group, and the MH codeword with this extracted number of bits is
Since the H code expansion table is referred to and converted into an uncompressed code, the capacity of the MH code expansion table can be reduced.

In the invention of claim 5, a drawing color is determined, an arbitrary MH code word is extracted from the MH code data, and the extracted MH code word is converted into an uncompressed code by referring to an MH code expansion table. Convert to know the amount of drawing.

(Embodiments) Hereinafter, embodiments of the MH code decompression method and drawing device of the present invention will be described based on the drawings. FIG. 1 is a block diagram showing a schematic configuration of an embodiment of a drawing apparatus according to the present invention.

In FIG. 1, data sent from the host computer 1 includes character data la's graphic data lb stored in the character data buffer, graphic data buffer, and image data buffer of the host computer 1, respectively.
, and image data IC (MH code data).In particular, the image data is compressed using an MH code word, which is a compression code.

The drawing device 2 includes a character expansion processing section 2a and a graphic expansion processing section 2b for performing processing corresponding to each data type such as the character data 1a, the graphic data lb, and the image data 10 transferred from the computer 1.

It has a configuration divided into an image development processing section 2C.

Among these processing units, the image development processing unit 2c is composed of five processing units described below.

(1) An image data control processing unit 2cl that sets drawing attributes of image data; (2) an MH code expansion processing unit 2c2 that performs expansion processing from an MH code word, which is a compressed code, to an uncompressed code; (3) Clip processing unit 2c3 that monitors the drawing area
, (4) a drawing processing section 2c4 that performs drawing of uncompressed codes, and (5) an offline data processing section 2c5 that performs line density conversion of image data to be drawn during offline drawing.

Image data is subjected to drawing processing by passing through each of the processing units described above.

Next, a description of the operation of the embodiment of the drawing apparatus described above and a description of the MH code decompression method using the fixed extraction method based on claims 1 and 2 will be provided. The terminating code words of the MH code applied to this invention are shown in Tables 1 and 2 below, and the make-up code words are shown in Table 3, respectively.

(Margins below) Figure 2 is an explanatory diagram of the M)l code decompression method using this fixed extraction method.As shown in Figure 2, the image data 1c stored in the image data buffer of the host computer 1. In step 1, 13 bits from the leading bit of certain MH code data are extracted using a fixed extraction method.

13 bits here indicates the maximum length of the MH code word. This extracted 13-bit MH code is converted to M in step 2.
The address of the code expansion table 3 is calculated by adding it to the base address of the MH code expansion table 3 as the offset amount of the H code expansion table 3.

Next, the calculated MH code expansion table address (001G
000000011) Refer to BiN, step 3
As a result, code length = 6 and drawing amount (uncompressed code) = 12 are obtained.

In this step 3, the code length "6" is added to the extraction start point "1" to calculate the next extraction start point "7" (rlJ
+r6J = r7J).

Thereafter, by repeating the above operations, the MH code is converted from a compressed code to an uncompressed code.

Further, the size of the MH code expansion table 3 is determined as follows.

2AXBXC=MH code expansion table capacity, where A is the number of bits of the MH code extracted from the image data=maximum code length of the MH code word=13 bits.

Further, B is the size of one MH code expansion table, and C is the genus of drawing colors (white drawing and black drawing).

The MH code expansion table capacity of the drawing device of this embodiment is 2
13X2X2=32 (K bytes).

Next, the decompression method using the division extraction method based on claims 1, 3, and 5 will be explained with reference to FIG.

In step 11, 8 bits from the leading bits of the MH code data, which is the image data in the image data buffer of the host computer 1, are extracted using a fixed extraction method.

Next, in step 12, the extracted 8-bit MH code is used as the offset amount in the MH code expansion table 4.
Add it to the base address of code extension table 4 and get MH
Calculate the address of the code extension table 4.

Referring to the address of the calculated MH code expansion table 4, if the code length is 8 or less, it means that one or more MH code words exist in the Ml code data extracted this time, and in step 13, the code length is =Q1 drawing amount (uncompressed code)=
Obtaining b means the end of one extension. In step 13, the code length is added to the extraction start point to find the next extraction start point.

However, if the code length of the MH code expansion table address calculated above is greater than or equal to 9 and less than or equal to 13, then in step 14, 5-bit MH code data is further extracted using the fixed extraction method.

The extracted 5-bit MH code is used as an offset amount for the MH code expansion table 5, and is added to the base address of the MH code expansion table 5 in step 15 to calculate the address of the MH code expansion table 5.

Referring to the calculated address of the MH code expansion table 5, the code length=Q and the drawing amount (uncompressed code)=C are obtained in step 16.

Next, the code length Q is added to the extraction start point to calculate the next extraction start point.

From the compressed code, by repeating the above operation,
Conversion to uncompressed code is performed.

The size of the MH code expansion table 5 when 8 bits and 5 bits are extracted twice in the above method is 2 (K
part-time job).

Next, a decompression method using a variable extraction method based on claims 1, 4, and 5 will be explained with reference to FIG.

fA) In the case of white drawing, it is determined in step 21 whether the first bit from the first bit of the MH code data, which is the image data in the image data buffer of the host computer 1, is "0" or "1".

If the result of this determination is "0", 12 bits from the first bit of the MH code data are extracted in step 22.

This extracted 12-bit extraction code is the address of MH code table address 6, (0010001011
011[1iN.

The 12-bit MH code extracted in step 22 is added to the base address of the MH code expansion table 6 as an offset amount for the MH code expansion table 6 in step 23, thereby calculating the address of the MH code expansion table 6.

The code length 6 and drawing amount 12 are obtained by referring to the address of this MH code expansion table 6, and the next extraction start point is determined as the extraction start point (rlJ) + code length (r6J) = next extraction start point (
r7J) is calculated.

If it is determined in step 21 that the first bit from the first bit of the MH code data is "1", then in step 24 six bits from the first bit of the MH code data are extracted.

This extracted 6-bit MH code is the address of the MH code expansion table 7, which is (10110118iN).

The 6-bit MH code extracted in step 24 is added to the base address of the MH code expansion table 7 as an offset amount for the MH code expansion table 7 in step 25 to calculate the address of the MH code expansion table 7.

Referring to the address of this MH code expansion table 7, the drawing amount 4 and code length 4 are obtained in step 25, and the next extraction start point is determined as extraction start point (r7J) + code length (r4J) = next extraction start point (rl IJ).

(In the case of Bl black drawing, it is determined in step 26 whether rlJ is set from the first bit to the fourth bit of the MH code data, which is the image data in the image data buffer of the host computer l.

If the result of this determination is UO, 13 bits from the leading bit of the MH code data are extracted in step 27.

This extracted 13-bit code is the address of the MH code expansion table 8, and is (0000011100011) BiN.

The extracted 13-bit MH code is converted to M in step 28.
The offset amount for the H code expansion table 8 is added to the base address of the MH code expansion table 8 to calculate the address of the MH code expansion table. Referring to the address of this MH code expansion table 8, code length 8 and drawing amount 1
4 is calculated, and the next extraction start point is calculated as extraction start point (1) ten code length (r8J)=next extraction start point (r9J).

Furthermore, if it is determined in step 26 that "1" is set from the first bit to the fourth bit of the MH code data 9, then in step 29, 6 bits from the first bit of the MH code data are extracted. .

This extracted 6-bit extraction code is M! (This is the address of the code extension table 9, fooollo) BiN.

The extracted 6-bit MH code is converted to MH in step 30.
The address of the MH code expansion table 9 is calculated by adding it to the base address of the MH code expansion table 9 as the offset amount of the code expansion table.

The code length "5" and the drawing amount "7" (uncompressed code) are obtained by referring to the calculated address of the MH code expansion table 9.

Next, the code length (r5J) is added to the extraction start point (r9J,) to calculate the next extraction start point.

From the compressed code, by repeating the above operation,
Conversion to uncompressed code is performed.

The size of the MH code expansion table 9 according to the above method is as follows.

White drawing (2” x 2) + (26 The relationship between the MH code expansion time and the MH code expansion table capacity is shown in Figure 5. In Figure 5, α represents the fixed extraction method, β represents the variable extraction method, and γ represents the divided extraction method. As shown in FIG. 5, the MH code expansion table capacity is 32 bytes for the fixed extraction method, 5.2 bytes for the variable extraction method, and 2 bytes for the divided extraction method.

(Effects of the Invention) As explained above, according to the invention of claim 1, since the image data is compressed by the MH code, which is a compression code, when the amount of image data to be drawn increases, for example, 2
Even if it becomes 2 times, 3 times, or ~n times, it will not be 2 times, 3 times, or ~n times because the image data is represented by compression code.
The point is that it can be shown with less image data.

According to the invention of claim 2, the maximum code length of the MH code word is 13.
Since bits are extracted using a fixed extraction method, it is possible to convert a compressed code into an uncompressed code by reading the MH code only once.

In addition, since the decompression process is performed using a single fixed extraction method, it is possible to simplify the process compared to divided extraction, variable extraction, or other methods.

According to the invention of claim 3, the maximum code length of 13 bits of the Mal code word is extracted by division from the MH code data by the division extraction method, and the maximum code length of 13 bits of the Mal code word is extracted by division until the relationship (code length ≧ number of extracted bits) is satisfied. By performing code extraction and access to the MH code expansion table, it is possible to reduce the capacity of the MH code expansion table.

According to the invention of claim 4, before extracting the MH codeword, the features of the individual MH codewords are grouped together, and extraction is performed in accordance with the group, and the number of bits to be extracted is set according to the group. Since the MH code word with the extracted number of bits is converted into an uncompressed code by referring to the MH code expansion table, it is possible to both reduce the MH code expansion table capacity and improve the MH code expansion speed. It has the effect of making it possible to satisfy the following.

Furthermore, according to the invention of claim 5, the drawing color is determined and M
An arbitrary MH code word is extracted from the H code word data, and the extracted MH code word is converted to an uncompressed code by referring to the MH code expansion table to know the amount of drawing.
The capacity of the MH code expansion table can be reduced, and the M
This has the effect of making it possible to improve the H code decompression speed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a schematic configuration of the drawing device of the present invention, FIG. 2 is a schematic explanatory diagram of the MH code decompression method of the present invention applying the fixed extraction method, and FIG. A schematic explanatory diagram of the MH code decompression method of the invention, FIG. 4 is a schematic explanatory diagram of the MH code decompression method of the present invention applying a variable extraction method, and FIG. One MI (code decompression time and M
FIG. 3 is an explanatory diagram showing the relationship between H code expansion table capacities. 1... host computer, 1a... character data,
1b...Graphic data, 1c...Image data, 2
...Drawing device, 2a...Character expansion processing unit,
2b...Graphic expansion processing unit, 2c...Image expansion processing unit, 2cl...Image data control processing unit, 2c2...MH code expansion processing unit, 2c3...Clip processing unit, 2c4... Drawing processing unit, 2c5...Offline data processing unit, 3 to 7...M
H code expansion table. Figure 2 Figure 3

Claims (5)

[Claims] (1) An MH code expansion method characterized by converting an MH code word into an uncompressed code by referring to an MH code expansion table corresponding to each MH code. (2) Extract from MH code data using a fixed extraction method so that one extraction always includes at least one MH code word, and use this extracted MH code word in a single MH code expansion table. M characterized in that it is converted into an uncompressed code by referring to
H code expansion method. (3) From the MH code data, select A (A=1, 2, 3.
) Extraction is performed using the divided extraction method, and for each extraction, the MH code expansion table is referred to, and when one or more MH code words are extracted, the extracted MH code words are uncompressed. An MH code expansion method characterized by converting into a code. (4) B (B=1, 2,
3...) The number of bits to be extracted is set to a variable length according to the bit information of the bit, and the number of bits of the extracted variable length is M.
An MH code expansion method characterized by converting an H code word into an uncompressed code by referring to an MH code expansion table. (5) An MH code expansion table, a means for determining a drawing color, a means for extracting an arbitrary MH code word from the MH code data, and an MH code word extracted by this means with reference to the MH code expansion table. and means for converting the data into an uncompressed code.