JPH07184067A - Binary image companding processing system and binary image segmentating method - Google Patents

Abstract

PURPOSE:To execute partial segmentation of an image at a high speed even from a binary image of a large size. CONSTITUTION:In order to generate a partial image by a binary image compander 20 provided with a decoding section 220 having a decoding circuit 222 decoding code data, a pointer 224 representing a decoded address, a register 228 instructing a color of a decoded code, a processing section 240 setting a run length of image data based on a change point detected from reference line image data and the decoding result of the code, a generating section 260 generating image data depending on the run length, reference line image data of each area obtained by dividing he binary image in horizontal and vertical directions, a run length in one dot before a succeeding changing picture element based on each divided position of an area, a coding start position corresponding to the changing picture element and color data of the image generated from the start position are registered in advance for each line at each divided position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a binary image compression / decompression processing system and a binary image clipping method for partially clipping large size image data.

[0002]

2. Description of the Related Art In a binary image compression / expansion processing system which handles a large amount of binary images, binary images are often coded and handled in order to speed up data transfer. This species,
As a typical encoding method used in the device, MH
There are (Modified Huffman) system, MR (Modified READ) system, and MMR (Modified MR) system.

In the MR system and the MMR system, the image is horizontal,
Focusing on the strong correlation in both vertical directions, it is based on the vertical mode code that compresses data by removing its redundancy.

The code of the vertical mode will be briefly described as follows.
The image of one sheet is decomposed into scanning lines composed of rows of black and white dots, and the encoding process is performed while scanning the scanning lines from left to right. The scan lines are processed from top to bottom.

The position (change point) at which dots are inverted in black and white on the scanning line to be encoded (encoding line) is expressed as a relative dot position with reference to the corresponding changing point on the scanning line (reference line) immediately before it. This is the vertical mode code word.

The code of the vertical mode is defined using the following three types of change points. (1) Point a0: a change point whose position is described by the immediately preceding codeword. (2) a1 point: This position is coded at the first change point to the right of the a0 point on the coding line. (3) b1 point: on the reference line to the right of a0 point,
A change point that changes in the same direction as point a (white to black or black to white).

With respect to the dot position of the b1 point as a reference, how many dots the a1 point is displaced to the left or the right (indicated by the relative position δ) is described by a variable length code. The length of the code word that frequently appears is shortened to minimize the length of the entire coded code data. In the vertical mode, a code word with a length of 1 bit to 7 bits is used.

In order to restore the original image from the data encoded in the vertical mode, usually, a connection of dots of only one of white and black (called a run) is sequentially generated by the following procedure. (1) Decode the code to obtain δ. (2) The reference line is scanned to find the position of point b1. (3) δ is added to the position of the b1 point to obtain the position of the a1 point. (4) Generate a run starting from point a0. (5) The a1 point is set as the new a0 point and the black and white are inverted. (6) Repeat from (1) for the next run.

Conventionally, when a partial image is cut out from the code data corresponding to the whole image encoded by such an encoding method, all the code data are expanded to obtain the original image. After unfolding, the desired image was cut out.

As another method, the applicant of the present invention has previously described, in Japanese Patent Application No. 3-183689, each of a plurality of segments obtained by dividing a binary image into a predetermined number of lines. A table is created in which the image data of the reference line corresponding to the start line of the segment and the data indicating the code position of the beginning of the start line in the code data when the binary image is compressed are created and stored in the table. We propose a method to expand the image from the middle by using each data.

[0011]

However, in the method of cutting out an image after the original image is expanded, a large amount of even unrelated images must be expanded, which increases the size of the original image. Accordingly, there is a problem in that the decompression process takes time and a huge amount of image memory is required.

Further, in the method shown in Japanese Patent Application No. 3-183689, a binary image can be cut out at a higher speed than a method of cutting out an image after developing the original image, but a predetermined line In the case of cutting out an image smaller than a segment obtained by dividing every number, an image of an unnecessary portion in the segment is also developed, and it takes more time than necessary.

The present invention has been made in view of the above points, and it is a binary image compression / decompression which enables high speed partial clipping of an image even from code data corresponding to a large size image. An object is to provide a processing system and a binary image cutout method.

[0014]

According to the present invention, in a binary image compression / expansion processing system for compressing / expanding a binary image, the binary image is horizontally divided by a predetermined number of lines and vertically by a predetermined dot. Image data of the reference line corresponding to the start line of the horizontally divided area and the next change based on the division position of the vertically divided area for the multiple areas obtained by dividing Table creating means for creating a table in which a run length up to one dot before a pixel, a start position of a code corresponding to the changed pixel, and color data indicating a color of an image generated from the start position are registered; Based on the contents of the table created by the table creating means, the partial image in the binary image is converted from the corresponding code data in the code data corresponding to the entire binary image. And characterized by including a partial image generating means for forming.

Further, according to the present invention, a decoding circuit for decoding code data obtained by compressing a binary image, an instruction means for indicating a code decoding position of the decoding circuit, and a position instructed by the instruction means. From the decoding means having a color designating means for designating the color of the code decoded by the decoding circuit, and detecting the change point from the reference line image data corresponding to the code data decoded by the decoding means,
Provided are processing means for setting a run length of image data to be generated based on the same change point and the decoding result by the decoding means, and generating means for generating image data according to the run length set by the processing means. A binary image compression / decompression device, the binary image is divided into a predetermined number of lines in the horizontal direction and a predetermined number of dots in the vertical direction during compression or expansion of the entire binary image. The image data of the reference line corresponding to the start line of each of the horizontally divided regions for the plurality of regions obtained by the above, and one of the following change pixels based on each divided position of the vertically divided region. A table in which a run length up to a dot, a start position of a code corresponding to the changed pixel, and color data indicating a color of an image generated from the start position are registered for each line for each division position. And the run length registered in the table created by the table creating means to the processing means, the start position of the code to the instructing means, and the color data to the color instructing means. And table data setting means for giving the image data of the reference line to the processing means.
The table data setting means sets the data corresponding to the partial image in the binary image so that only the partial image is expanded.

Further, the present invention is obtained by dividing the binary image into a predetermined number of lines in the horizontal direction and a predetermined number of dots in the vertical direction when the compression process or the expansion process is performed on the entire binary image. Image data of a reference line corresponding to the start line of each of the horizontally divided regions for a plurality of regions and up to one dot before the next change pixel based on each divided position of the vertically divided regions Of the run length, the start position of the code corresponding to the changed pixel, and the color data indicating the color of the image generated from the start position are created in advance for each line for each division position, and a table is created in advance. When decompressing the partial image based on the code data corresponding to the entire value image, the decompression process is started from the table by using each data corresponding to the start position of the partial image, Characterized in that in the generated time finishes the decompression processing.

[0017]

According to this structure, a plurality of areas obtained by dividing a binary image by a predetermined number of lines in the horizontal direction and a predetermined number of dots in the vertical direction are divided into image areas by area. By creating a table in which data that can be decompressed is registered, it is possible to obtain a desired partial image from the entire binary image by decompressing only the necessary part.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a binary image compression / expansion processing system to which the binary image data cutout method according to this embodiment is applied.

As shown in FIG. 1, the binary image compression / expansion processing system includes a CPU 10, a memory 12, and an external storage device 1.
4, an image input device 16, a bit map memory 18, a binary image compression / expansion device 20, and a display device 21 are provided.

CPU 10, memory 12, external storage device 1
4, image input device 16, and binary image compression / decompression device 20
Are mutually connected via the system bus 22.
Further, the CPU 10, the memory 12, the bitmap memory 1
The 8 and binary image compression / decompression devices 20 are connected to each other via an image bus 24.

The CPU 10 controls the entire system, and operates according to a program stored in the memory 12. The memory 12 is for storing programs for operating this system, various data, and the like. In particular, the code data given to the binary image compression / expansion device 20 at the time of the image expansion process, and the intermediate data referred to when the binary image compression / expansion device 20 performs the image expansion process of cutting out a part of the image from the code data. A start table (described later) is stored.

The external storage device 14 is for storing image data and code data. The image data can be input to this system by the image input device 16, and the image data and the code data may be given from the outside.

The image input device 16 is composed of, for example, an ITV, a scanner device or the like, and generates and inputs image data. The image data input by the image input device 16 is stored in the external storage device 14.

The bitmap memory 18 stores the image input by the image input device 16 and the binary image compression / expansion device 2.
This is for storing display image data when displaying an image or the like expanded by 0 on the display device 21.

The binary image compression / decompression device 20 executes a compression process for compressing image data and a decompression process for decompressing the code data obtained by the compression process to develop the original image.

FIG. 2 is a block diagram showing the detailed arrangement of the binary image compression / decompression device 20 shown in FIG. As shown in FIG. 2, the binary image compression / decompression device 20 includes a decoding unit 220,
Processing unit 240, generation unit 260, and I / O register group 2
80 is provided.

The decoding section 22 inputs the data to be processed (code data at the time of expansion processing, image data at the time of compression processing) via the system bus 22, and decodes the contents of the data. The decoding circuit 222 , A pointer 224, a byte counter 226, and a register 228 are provided.

The decoding circuit 222 inputs the code data at the time of image expansion and the image data at the time of image compression to decode the data. At the time of decompression processing, if the decoding result is a code word in the vertical mode, position data δ (relative position between a1 point and b1 point) is output to the processing unit 240 (others, horizontal mode, pass mode, one-dimensional code). The corresponding data is output). During compression processing, a
One point is detected and output to the processing unit 240. Further, the decoding circuit 222 outputs the code length of the decoded code data and updates the value of the pointer 224 during the expansion processing.

The pointer 224 is a register for storing data indicating the position where the decoding circuit 222 starts decoding, and indicates the starting position of decoding start for the code data at the time of decompression processing and the position of a0 point at the time of compression processing. The data of the pointer 224 is updated according to the processing by the decoding circuit 222.

The byte counter 226 has a decoding circuit 222.
It counts the number of bytes of data input to. The register 228 stores color data decoded by the decoding circuit 222 (corresponding to white “0” and black “1”).

Next, the processing section 240 detects point b1 (color change point) from the reference line image data, and a change point detection circuit 241, a calculation circuit 242, a run length counter 244, and a line counter 255 are provided. Has been.

The change point detection circuit 241 detects a change point (point b1) from the image data of the line (reference line) immediately before the line to be compressed or expanded, which is stored in the reference line image memory. Is.

During the decompression process, the arithmetic circuit 242 uses the position of the point a0 indicated by the pointer 243 as a starting point, and the point b1 detected by the change point detection circuit 241 and the decoding section 220.
The a1 point, that is, the length (run length) of the image to be generated is obtained from the position data (δ) obtained by. Further, at the time of compression processing, from the b1 point detected by the change point detection circuit 241 and the a1 point obtained by the decoding unit 220,
The relative position (δ) between the points a1 and b1 is obtained (vertical mode). This position data δ is used by the generation unit 260 to specify the corresponding code data.

The pointer 243 is a change point detection circuit 24.
1, which is referred to in the processing in the arithmetic circuit 242,
Data indicating the position of point a0 is stored. The run length counter 244 counts the run length from the start position of the generated run.

The line counter 255 counts up to the number of lines n which defines the divided area set in the I / O register group 280 every time the image compression / expansion process is executed for one line of the image. The number of lines in a divided area obtained by dividing the entire image by a predetermined number of lines is counted.

Next, the generation unit 260 generates image data at the time of image expansion processing and code data at the time of image compression processing based on the a1 point (run length) or position data (δ) detected by the processing unit 240. Is generated and image data is generated at the time of image expansion processing, and a generation circuit 262, a pointer 264, and a byte counter 266 are provided.

At the time of image compression, the generation circuit 262 obtains a code according to the position data (δ) detected by the processing unit 240 (others, horizontal mode, pass mode, one-dimensional code) and connects the codes. It also generates code data. Also, during the image expansion processing,
According to the a1 point (run length) detected by the processing unit 240, data of white “0” or black “1” are connected to generate image data.

The pointer 264 is used for the image compression processing.
The bit position of the head to which the code in the code data is to be connected is shown to the generation circuit 262, and the position of a0 point is shown at the time of the image expansion processing. Pointer 26
4 is updated with the code length of the code that has been joined together during the image compression processing, and is updated with the a1 point (run length) output by the arithmetic circuit 242 of the processing unit 240 during the image expansion processing.

The byte counter 266 counts the byte length of the code data created by the generation circuit 262 during the image compression processing, and the byte length of the image data created by the generation circuit 262 during the image expansion processing by I.
The number of dots is counted up to the number of dots m that defines the divided area set in the / O register group 280.

The I / O register group 280 holds various data used for compression / expansion processing in the same apparatus. In the I / O register group 280, the number of lines n (in the horizontal direction) for dividing an image into a plurality of divided areas is included. It includes a register for setting the division) and the number of dots m (division in the vertical direction).

Next, the data structure in this embodiment will be described. FIG. 3 shows a conceptual diagram of the image data 30 corresponding to the entire original image. FIG. 4 is a conceptual diagram of the horizontal intermediate start table 40 used when partial image clipping is performed, and FIG. 5 is a conceptual diagram of the vertical intermediate start table 50 used when partial image clipping is performed. The horizontal intermediate start table 40 and the vertical intermediate start table 50 are generated during the first compression processing or decompression processing (details will be described later).

The image data 30 shown in FIG. 3 is divided into a plurality of regions in the horizontal direction for every n lines and further into a plurality of regions in the vertical direction for every m dots.
It is divided into 0-2, ....

In the horizontal intermediate start table 40 shown in FIG. 4, the reference line corresponding to the head line of each horizontally divided area (see FIG. 4A) in the image data 30 shown in FIG. Image data (reference line image data)
Is stored. In the reference line image data corresponding to the first line (encoding line) of the area 0 shown in FIG. 4A, all bits are “0” indicating white.

The vertical intermediate start tables 50-0, 50-1, ... Shown in FIG. 5 have the image data 3 shown in FIG.
Vertically divided areas in 0 (see FIG. 5 (a))
At the division position (position 0, position 1, ...) Of each region up to one dot before the next change pixel and the start position of the code corresponding to the change pixel (coding start pixel a0 point) , And the color of the image to be generated are stored in association with each line.

The horizontal intermediate start table 40 stores reference line image data which is referred to in order to expand each area (area shown in FIG. 4A) in the image data 30, and the vertical intermediate start data 50. -0, 50-1,
Stores information referred to in order to extend from the division position (position 0, position 1, ...) Of each area. Therefore, for example, when partially cutting out an image from the code data corresponding to all images, areas 30-1, 30-2, ... Including the partial image to be cut out in the image data 30 shown in FIG.
, The information for expanding the corresponding divided area in the code data is provided to each of the intermediate start tables 40, 50-.
By referring from 0, 50-1, ..., If the decompression process is started from the address and the decoding of the required number of dots and lines is completed, the decoding is aborted there to improve the efficiency of the required image. It is possible to cut out.

Next, the operation of this embodiment will be described.
First, the horizontal intermediate start table 40 and the vertical intermediate start table 50-0, shown in FIGS.
The procedure for creating 50-1, ... Will be described. The intermediate start tables 40, 50-0, 50-1, ... Are used when the image data of the image input by the image input device 16 (or image data given from the outside) is first compressed. In addition, necessary data is acquired and generated during the compression process. Alternatively, when the code data obtained by the compression process is given from the outside, when the decompression process is performed on the entire image first, necessary data is acquired and generated in the decompression process. Each intermediate start table 40, 50-0, 50-
After the creation of 1, ...

First, regarding the table creation processing when the given original data is image data (image compression processing),
This will be described with reference to the flowchart shown in FIG. First, the CPU 10 accesses the I / O register group 280 and sets the number of lines n and the number of dots m that define the divided area in the image data 30 (step A).
1).

The CPU 10 transfers the image data to be compressed to the decoding circuit 222 of the binary image compression / decompression device 20 via the system bus 22, and also transfers the reference line image data to the processing unit 240 for compression processing. Is started (step A2).

The binary image compression / expansion device 20 sequentially performs image compression processing on input data. At this time, the number of dots of the image data processed by the byte counter 226 is counted, and it is determined whether or not the processing for m dots set in the I / O register group 280 has been executed (step A3).

When the count value of the byte counter 226 reaches a predetermined value (m) (when the processing for m dots is executed), the binary image compression / decompression device 20 generates a CPU interrupt.

Here, the CPU 10 runs the fractional run length beyond the position defining the divided area (run length up to one dot before the next change pixel) and the color data of this run (white "0" or black). "1") is read from the register 228,
It is registered in the vertical intermediate start table of the memory 12 (corresponding to the corresponding position).

The CPU 10 also determines the code position (byte position, bit position) starting from the dot next to the fractional run,
It is read from the byte counter 266 and the pointer 264, respectively, and registered in the vertical start table in the memory 12 at the position (position 0, 1, ...) That defines the divided area (steps A3, A4).

The above registration in the vertical intermediate start table is performed at the position (position 0, 1,
...) for each line. As a result, vertical intermediate start tables 50-1, 50-1, ... Corresponding to the respective positions are created (see FIG. 5).

On the other hand, every time the processing for one line is executed,
The line counter 255 counts the number of lines of the processed image (step A5). When the count value of the line counter 255 reaches a value indicating that the processing for the preset number of lines (n) is completed, the binary image compression / decompression device 20 generates a CPU interrupt.

The CPU 10 registers the image data of the last line of the divided area (reference line image data for the divided area of the next stage) in the horizontal intermediate start table 40 of the memory 12 (step A6).

Targeting the above processing for image compression processing 1
This is performed for the entire image for pages (step A7).
And the horizontal intermediate start table 4 for one page
0 and vertical intermediate start tables 50-1, 50-
When 1, ... Are stored in the memory 12, the CPU 10 registers the contents of each table in the external storage device 14 (step A8).

Next, a table creating process when the given original data is code data (image expansion process) will be described. The table is created by the same procedure as the image compression processing described above. However, the number of dots of the image data processed by the byte counter 266 is counted, and it is determined whether or not the processing for m dots set in the I / O register group 280 has been executed.

When the count value of the byte counter 266 reaches a predetermined value (m), the byte counter 226,
The code position is read from the pointer 224 and the memory 12
Registered in the vertical start table inside. In addition, as for the run length of the fraction, the count value of the byte counter 266 is m.
Is a fraction of the run length indicated by the run length counter 244.

Next, the intermediate start table (horizontal direction,
A specific operation of performing a partial decompression process (partial image cutout) using the vertical direction) 40, 50-0, 50-1, ... Will be described with reference to the flowchart shown in FIG.

When the image is cut out, the decompression processing is started from the nearest divided area (start area) closest to the desired cut-out area. Therefore, first, before starting the decompression process,
A binary image compression / decompression device that determines the number of lines (vertical size) and the number of bytes (horizontal size) indicating the range (size of the image to be cut) that is the target of decompression processing from the partial area (start area) where decompression processing starts 20 I / O register groups 280 are set (step B1).

Next, the reference line image data corresponding to the start area is read from the horizontal intermediate start table 40 of the image to be expanded and set in the reference line image memory (the reference line image data is stored in the processing unit 240). It is given to the change point detection circuit 241) (step B2).

Next, of the vertical intermediate start table of the image to be decompressed, the run length from the vertical intermediate start table at the position corresponding to the start area is calculated.
The code position and color data are read. Then, the run length is set in the run length counter 244, the bit position of the code position is set in the pointer 224, the byte position of the code position is set in the byte counter 226, and the color data is set in the register 228 (step B3).

After the setting of each data is completed, the image expansion processing of the partial image is started (step B4). First, an image with a run length of a fraction set in the run length counter 244 from the start position is generated. The generated image data is transferred to and stored in the bitmap memory 18 via the image bus 24.

On the other hand, the decoding circuit 222 of the decoding unit 220 is supplied with the code data to deal with the image expansion processing. The decoding unit 220 includes a byte counter 226 and a pointer 22.
4. Decode the code data according to the contents of the register 228 (color data). The processing unit 240 also detects a change point from the reference line image data stored in the reference line image memory. According to the result of this decoding, the generation unit 26
0 generates image data. The image data is sequentially stored in the bitmap memory 18 via the image bus 24.

The byte length of the generated image data is counted by the byte counter 266 (step B5). When the number of bytes reaches the number of bytes set in step B1, the process for the currently targeted line is completed, and the binary image compression / decompression device 20 generates a CPU interrupt. As a result, the process for the next line starts. At the start position of the next line, the run length, code position, and color data are set in the same manner as described above, and the image data is generated by decoding from the code data corresponding to that position.

Thereafter, image data is sequentially generated from the input code data. The image expansion processing here is performed only on the divided areas including the partial image to be cut out. Further, the number of lines of the generated image data is counted by the line counter 255 (step B6). When the number of lines reaches the number of lines set in step B1, the generation of the image data of the desired partial image is completed, and the binary image compression / decompression device 20 generates a CPU interrupt. That is, if the image decompression processing for the required number of lines is completed even in the middle of one divided area, the decompression processing is terminated there.

In this way, with respect to a plurality of divided areas obtained by dividing the image in the horizontal and vertical directions for every n lines and m dots, each of the areas obtained by dividing the image in the horizontal direction corresponds to the leading line. The reference line image data to be created is created as the horizontal intermediate start table 40, and the fractional run length, the code position, and the color data are associated with each other for each position that defines an area obtained by dividing the image in the vertical direction. Horizontal intermediate start tables 50-0, 50-1, ... Are created for each line.

Therefore, each intermediate start table 40, 5
By setting the data registered in 0-0, 50-1, ... In a predetermined portion of the binary image compression / expansion circuit 20, image data of only a desired partial image in the entire image is generated. Image expansion processing becomes possible.

In this method, since the expansion processing is not performed on a large number of images that are not directly related to each other, the partial images can be cut out efficiently, and a huge image memory capacity is not required.

[0070]

As described above, according to the present invention, the reference line image corresponding to each area obtained by horizontally dividing the image data for each predetermined line at the time of the compression processing or the expansion processing of the image. This information is used because the data, the run length of the fraction, the code position, and the color data for each line for each position that divides the area obtained by dividing in the vertical direction for each predetermined dot are stored in association with each other. As a result, the image can be partially cut out at high speed.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a binary image compression / expansion processing system to which a binary image data cutout method according to an embodiment of the present invention is applied.

FIG. 2 is a block diagram showing a detailed configuration of a binary image compression / decompression device 20 shown in FIG.

FIG. 3 is a conceptual diagram of image data corresponding to an original image.

FIG. 4 is a conceptual diagram for explaining a horizontal intermediate start table 40 in the present embodiment.

FIG. 5 is a conceptual diagram for explaining vertical intermediate start tables 50-0, 50-1, ... In the present embodiment.

FIG. 6 is a flowchart for explaining a procedure of table creation processing in this embodiment.

FIG. 7 is a flowchart for explaining a procedure of a process of cutting out a partial image using the intermediate start table in the present embodiment.

[Explanation of symbols]

10 ... CPU, 12 ... Memory, 14 ... External storage device, 1
6 ... Image input device, 18 ... Bitmap memory, 20 ...
Binary image compression / decompression device, 21 ... Display device, 22 ... System bus, 24 ... Image bus, 220 ... Decoding unit, 222
... Decoding circuit, 224 ... Pointer, 226 ... Byte counter, 228 ... Register, 240 ... Processing section, 241 ... Change point detection circuit, 242 ... Operation circuit, 244 ... Run length counter, 255 ... Line counter, 260 ... Generation section,
262 ... Generation circuit, 264 ... Pointer, 266 ... Byte counter, 280 ... I / O register group.

Claims (4)

[Claims] 1. A binary image compression / expansion processing system for compressing / expanding a binary image, wherein the binary image is obtained by dividing the binary image by a predetermined number of lines in a horizontal direction and a predetermined number of dots in a vertical direction. For a plurality of areas, the image data of the reference line corresponding to the start line of the horizontally divided area and the run up to one dot before the next change pixel based on the division position of the vertically divided area A length, a start position of a code corresponding to the change pixel,
And a table creating unit that creates a table in which color data indicating the color of the image generated from the start position is registered, and a portion in the binary image based on the contents of the table created by the table creating unit. Partial image generating means for generating a specific image from the corresponding code data in the code data corresponding to the entire binary image, and a binary image compression / decompression processing system. 2. The binary image compression / expansion processing system according to claim 1, wherein the table creation means creates the table when performing expansion processing or compression processing for the entire binary image. 3. A decoding circuit for decoding code data obtained by compressing a binary image, instruction means for indicating a code decoding position of the decoding circuit, and the decoding circuit from the position instructed by the instruction means. Decoding means having a color designating means for designating the color of the code to be decoded by the deciphering means, and detecting a change point from the reference line image data corresponding to the code data decoded by the deciphering means. A binary image compression / decompression device provided with processing means for setting a run length of image data to be generated based on a decoding result, and generation means for generating image data according to the run length set by the processing means. And when performing compression processing or decompression processing for the entire binary image,
A reference line corresponding to the start line of each region divided in the horizontal direction for a plurality of regions obtained by dividing the binary image in the horizontal direction by a predetermined number of lines and in the vertical direction by a predetermined number of dots. Of the image data, the run length up to one dot before the next change pixel based on each division position of the vertically divided area, the start position of the code corresponding to the change pixel, and the start position. Table creating means for creating a table in which color data indicating the color of the image is registered for each line for each of the division positions; and the processing means for processing the run length registered in the table created by the table creating means. In addition, the start position of the code is set in the indicating means, the color data is set in the color indicating means, and the image data of the reference line is given to the processing means. A binary image compression, wherein the table data setting means sets data corresponding to a partial image in the binary image to perform decompression processing only on the partial image. Extension processing system. 4. A plurality of regions obtained by dividing the binary image by a predetermined number of lines in the horizontal direction and by a predetermined number of dots in the vertical direction during compression or expansion of the entire binary image. On the other hand, the image data of the reference line corresponding to the start line of each area divided in the horizontal direction and the run length up to one dot before the next change pixel based on each division position of the area divided in the vertical direction , A starting position of a code corresponding to the changed pixel and color data indicating a color of an image generated from the starting position are registered in advance for each line for each division position, and the entire binary image is created. When decompressing the partial image based on the code data corresponding to, the decompression process is started from the table by using each data corresponding to the start position of the partial image, and the partial image is generated. Binary image extraction method, characterized by terminating the decompression processing at point.