JPH07298260A - Compressor for image data, compression method for image data, expansion device for image data, image data expansion method and compression expansion system for image data - Google Patents

Abstract

PURPOSE:To implement efficiently compression and expansion of image data. CONSTITUTION:A CPU 1 receives sequentially an image data string of a transfer object from an image memory 3a to discriminate whether or not same image data are consecutive, and outputs the image data discriminated not consecutive as they are without conversion and counts consecutive number of image data groups discriminated to be consecutive and outputs the data to be converted into two data comprising image data and consecutive number data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for compressing / decompressing image data to be transferred in a data processing device.

[0002]

2. Description of the Related Art As conventional image data compression / expansion methods, there are PackBits encoding method used for storing image data in a host device and MH encoding method used in G3 facsimile. . These methods compress data by encoding a binary image data in order to reduce the amount of memory used in a storage device such as a magnetic disk and the data transfer time.

Here, the outline of a conventional image data compression / decompression method will be described by taking the PackBits encoding method as an example. Note that the PackBits encoding method is used when the same color data such as white data and black data is continuous.
This is a coding method that enables data compression because the continuous length is calculated and the amount is expressed by a code.

First, compression / expansion of image data will be described with reference to FIGS. 9, 10 and 11. The ninth
The figure shows an example of image data compression by the PackBits encoding method. In the data shown in this example, 20-byte data is compressed to 11 bytes. FIG. 10 shows an example of a program for decompressing compressed data. FIG. 11 shows the structure of image data compressed / uncompressed by the PackBits encoding method.

As shown in FIGS. 9 and 11, PackB
In the its encoding method, a code called "TAG" is always added before image data, and in the case of continuous image data, the amount of continuous data (continuous number) is indicated by 1-byte "TAG", and then It means that the 1-byte image data following is continued for the continuous number. Even if the image data is not continuous, calculate the discontinuous image data amount and set the discontinuous data length (discontinuous number) to 1
It is indicated by a byte “TAG”, which means that image data for the discontinuous data amount follows.

However, regardless of compression / non-compression, "TA
Since "G" data is 1 byte, "TAG" must be added to the image data after a maximum of 127 bytes. In the case of the continuous / discontinuous number of data exceeding 127 bytes, the data starts again from the "TAG" data. Note that compression and decompression are performed by, for example, P shown in FIG.
It can be realized relatively easily by software, like the ackBits decompression program.

[0007]

However, in the above-described conventional image data compression / decompression method, the above-mentioned "TAG" data is always required before the continuous / discontinuous image data, and therefore, extra data is required. There was a problem that the amount would increase. For example, when all are discontinuous data, a certain amount of "TAG" data is added in addition to the normal image data, so that not only the data compression is not performed, but also the data amount becomes large. Will occur.

Further, in the conventional image data compression / decompression method, since the above-mentioned "TAG" data represents a continuous number / a discontinuous number in 1 byte, a maximum of 12 is actually used.
This means that only 7 bytes of image data can be handled by one "TAG" data, and if 128 or more 1 byte of the same image data continues and the image data to be compressed is 128 bytes or more, this compression method Then, there is a drawback that overflow occurs, and it is necessary to generate data including "TAG" again. That is, in the conventional image data compression, there has been a problem that the numerical overflow of the data to be compressed must be always taken into consideration, and the upper limit of the compression rate is also determined.

The present invention has been made under such a background, and a first object thereof is to enable efficient compression / expansion of image data.

A second object of the present invention is to enable efficient compression / decompression of image data, and to perform compression with no upper limit of compression ratio without considering numerical overflow of the data to be compressed. It is to be.

[0011]

In order to achieve the first object, the image data compression apparatus according to claim 1,
A storage means for storing discontinuous image data in the image data string to be transferred without replacement, and an image data group in which the same image data is continuous are replaced with one of the image data and the continuous number data of the image data. And a replacement means for performing the replacement.

In order to achieve the first object, the sixth aspect is provided.
The image data compression apparatus described above includes a determination unit that sequentially captures image data strings to be transferred and determines whether or not the same image data is continuous, and an image determined by the determination unit as not continuous. First output means for outputting the data as it is, counting means for counting the number of consecutive image data discriminated as being consecutive by the discriminating means, one of the continuous image data and the counting means. And second output means for outputting the continuous number data counted by.

In order to achieve the first object, the first aspect
In the image data compression method described in 1, the discontinuous image data of the image data string to be transferred is stored as it is, and the image data group in which the same image data is continuous is replaced with one of the image data and the continuous number data. Is configured to.

In order to achieve the above-mentioned first object, claim 1
In the image data compression method described in 6, the image data string to be transferred is sequentially captured to determine whether or not the same image data is continuous, and the image data that is determined to be not continuous is not replaced. The image data group is output as it is, and the continuous number of the image data group determined to be continuous is counted, and the image data group is output after being replaced with two data, one of the image data and the continuous number data. .

In order to achieve the above-mentioned second object, claim 2
The image data compressing apparatus described in No. 1 is a storage unit for directly storing the discontinuous image data without replacing the discontinuous image data in the transfer target image data string, and an image data group in which the same image data is continuous is one of the image data. And a replacement unit for replacing the continuous number data expressed in the variable length data format of the image data with the length data of the continuous number data.

In order to achieve the second object, the second aspect
The image data compression apparatus described in No. 6 determines a non-continuous determination unit that sequentially captures image data strings to be transferred and determines whether the same image data is continuous, and the determination unit. First output means for outputting image data as it is, counting means for counting the number of consecutive image data discriminated by the discriminating means as continuous, one of the continuous image data and the counting It is provided with a second output means for outputting the continuous number data counted by the means and expressed in the variable length data format and the length data of the continuous number data.

In order to achieve the second object, claim 3
In the image data compression method described in 1, the discontinuous image data of the transfer target image data string is stored as it is without being replaced, and the continuous image data group is a continuous image data represented in the variable length data format. The number data and the length data of the continuous number data are replaced.

In order to achieve the second object, claim 3
In the image data compression method described in 6, the image data string to be transferred is sequentially captured to determine whether or not the same image data is continuous, and the image data that is determined to be not continuous is not replaced. For the image data group that is output as it is and is determined to be continuous, the continuous number is counted, one of the image data, the continuous number data expressed in the variable length data format, and the length of the continuous number data. The data is replaced with three data and output.

In order to achieve the above-mentioned first object, claim 4
In the image data decompression device described in 1, the discontinuous image data is not replaced, and the continuous image data group is compressed and transferred by replacing one of the image data and the continuous number of the image data. An image data decompression device for decompressing a compressed image data string, wherein the transferred compressed image data string is stored as it is without replacing the image data transferred without replacement, The replaced and transferred image data includes a replacement means for replacing the image data with the continuous number of image data strings.

In order to achieve the first object, it is preferable that:
The image data decompression device described in 6 does not replace discontinuous image data, but replaces an image data group in which the same image data is continuous with one of the image data and the continuous number data of the image data. An image data decompression device for decompressing a compressed and transferred compressed image data sequence, wherein it is determined whether or not the transferred compressed image data sequence is sequentially captured and is a target of compression. Determining means, first output means for directly outputting the image data determined as image data that cannot be compressed by the determining means, and image data that can be compressed by the determining means. The determined image data is the image data corresponding to the continuous number data. And a second output means for force.

In order to achieve the above-mentioned first object, claim 5
In the image data decompression method described in 1, the discontinuous image data is not replaced, and the image data group in which the same image data is continuous is replaced by one of the image data and the continuous number data of the image data. With respect to the compressed image data string that has been compressed and transferred, the image data that has been transferred without replacement is stored as it is without being replaced, and the image data that has been transferred after replacement has the continuous image data. The image data string for the number data is replaced.

In order to achieve the second object, the invention according to claim 5
In the image data decompression device described in 6, the discontinuous image data is not replaced, and the image data group in which the same image data is continuous is represented by one of the image data and the variable length data format of the image data. With respect to the compressed image data string transferred after being replaced by the number data and the length data of the continuous number data, the image data transferred without replacement is stored as it is without being replaced, and And a replacement unit that replaces the transferred and transferred image data with an image data string for the continuous number of data by referring to the length data.

In order to achieve the second object, the invention according to claim 6
In the image data decompression device described in 1, the discontinuous image data is not replaced, and an image data group in which the same image data is continuous is represented by one of the image data and a variable length data format of the image data. An image data decompression device for decompressing a compressed image data sequence compressed and transferred by replacing the number data and length data of the continuous number data, wherein the transferred compressed image data sequence is sequentially Discriminating means for discriminating whether or not the image data can be taken in and compressed, and first output means for directly outputting the image data discriminated by the judging means as image data that cannot be compressed. And the image determined to be image data that can be compressed by the determination means. It said Jideta with reference to the length data and a second output means for outputting only the consecutive number data minute.

In order to achieve the above-mentioned second object, claim 6
In the image data decompression method described in 6, the discontinuous image data is not replaced, and the image data group in which the same image data is continuous is represented by one of the image data and the variable length data format of the image data. Regarding the compressed image data string that has been compressed and transferred by replacing the number data and the length data of the continuous number data, the image data that has been transferred without compression is stored as it is without being replaced, and It is configured to replace the compressed and transferred image data with an image data string for the continuous number of data by referring to the length data.

In order to achieve the first object, the invention as set forth in claim 7,
The image data compression / decompression system described in No. 1 includes a first storage unit that stores the discontinuous image data of the transfer target image data string as it is without replacing it, and an image data group in which the same image data is continuous. First replacing means for replacing one of the image data with continuous number data of the image data, and the image data transferred without compression of the transferred compressed image data string is stored without replacement. And a second replacing means for replacing the image data transferred by the compression with the continuous number of image data strings.

In order to achieve the first object, claim 7
The image data compression / decompression system described in No. 6 sequentially captures the image data sequence to be transferred and determines whether or not the same image data is continuous, and a first determination unit that is continuous by the determination unit. First output means for directly outputting the image data determined to be not present, counting means for counting the number of consecutive image data determined to be continuous by the determining means, and continuous image data No. 1 and a second output means for outputting the continuous number data counted by the counting means, and whether or not it is image data which can be compressed by sequentially taking in the transferred compressed image data sequence. Second discriminating means for discriminating and image data discriminated by the discriminating means as image data which cannot be compressed. Is output as it is, and third output means for outputting the image data for which the determination is made by the determination means that the image data has been determined to be the image data that can be compressed by the continuous number data. Is equipped with.

In order to achieve the above-mentioned second object, claim 8
The image data compression / decompression system described in No. 1 includes a first storage unit that stores the discontinuous image data of the transfer target image data string as it is without replacing it, and an image data group in which the same image data is continuous. A first replacing means for replacing the image data, the continuous number data of the image data with the length data of the continuous number data, and the image data transferred without being replaced without being replaced. 2 storage means and 2nd replacement means for replacing the transferred and transferred image data by referring to the length data with the image data string for the continuous number data.

In order to achieve the above-mentioned second object, claim 8
The image data compression / decompression system described in No. 6 sequentially captures the image data sequence to be transferred and determines whether or not the same image data is continuous, and a first determination unit that is continuous by the determination unit. First output means for directly outputting the image data determined to be not present, counting means for counting the number of consecutive image data determined to be continuous by the determining means, and continuous image data , A second output means for outputting the continuous number counted by the counting means and the length data of the continuous number data, and the compressed image outputted and transferred from the first and second output means. Second determination means for determining whether the image data is image data that can be sequentially compressed by sequentially fetching data strings, and compression target by the determination means. Refer to the length data for the third output means for directly outputting the image data determined to be the image data that cannot be changed, and the image data determined to be the image data that can be compressed by the determination means. And a fourth output means for outputting only the continuous number data.

[0029]

According to another aspect of the present invention, in the image data compressing device, the storing means stores the discontinuous image data in the image data string to be transferred without replacing the same image data. The continuous image data group is replaced with one of the image data and the continuous number data of the image data so that the data amount is not increased and the image data is compressed / decompressed. Be able to do it efficiently.

In the image data compression apparatus according to the present invention, the discriminating means sequentially captures the image data string to be transferred and discriminates whether or not the same image data is continuous, and then the first output. The means outputs the image data, which is discriminated by the discriminating means as being not continuous, as it is. Then, the counting means counts the number of consecutive image data which is determined to be continuous by the determining means, and the second output means counts one of the continuous image data and the counting means. By outputting the continuous number data counted by, the data amount is not increased with respect to the uncompressed data, and the image data can be efficiently compressed / decompressed.

In the image data compression method according to the eleventh aspect, the discontinuous image data of the image data string to be transferred is stored as it is, and the image data group in which the same image data is continuous is continuous with one of the image data. By configuring the data to be replaced with the number data, the data amount is not increased with respect to the data that is not compressed, and the image data can be efficiently compressed / decompressed.

In the image data compressing method according to the sixteenth aspect, image data strings to be transferred are sequentially taken in and it is determined whether or not the same image data is continuous.
The image data determined to be non-continuous is output as it is without replacement, and the continuous number of image data groups determined to be continuous is counted, and one of the image data and the continuous number data are counted. By replacing the two data with the data and outputting the data, the data amount is not increased with respect to the data that is not compressed.
To enable efficient compression / decompression of image data.

According to a twenty-first aspect of the present invention, in the image data compression device, the storage means stores the discontinuous image data of the image data string to be transferred without replacement, and the replacement means stores the same image data. The image data group in which the image data is consecutive is replaced with one of the image data, the continuous number data expressed in the variable length data format of the image data, and the length data of the continuous number data, thereby compressing / decompressing the image data. It is possible to perform compression efficiently, and to perform compression without an upper limit of the compression rate without considering the numerical overflow of the data to be compressed.

According to a twenty-sixth aspect of the present invention, in the image data compression apparatus, the discriminating means sequentially takes in the image data sequence to be transferred and discriminates whether or not the same image data is continuous, and then the first output. The means outputs the image data, which is discriminated by the discriminating means as being not continuous, as it is. Then, the counting means counts the number of consecutive image data which is discriminated by the discriminating means, and the second output means,
Efficient compression / expansion of image data by outputting one of continuous image data, continuous number data counted by the counting means and expressed in a variable length data format, and length data of the continuous number data. Well done,
In addition, it should be possible to perform compression with no upper limit of the compression rate without considering the numerical overflow of the data to be compressed.

In the image data compression method according to the thirty-first aspect, the discontinuous image data of the image data string to be transferred is stored as it is, and the continuous image data group is represented by one of the image data and a variable length data format. By replacing the continuous number data and the length data of the continuous number data, the image data can be efficiently compressed / decompressed, and the upper limit of the compression rate can be achieved without considering the numerical overflow of the data to be compressed. It is possible to compress without any form.

A method of compressing image data according to a thirty-sixth aspect of the present invention is to sequentially fetch image data strings to be transferred and determine whether or not the same image data is continuous.
Image data that is determined not to be continuous is output without replacement, and the number of consecutive image data that is determined to be continuous is counted, and one of the image data and the variable length data format are used. By replacing the expressed continuous number data and the length data of the continuous number data with three data and outputting the data, the image data can be compressed / decompressed efficiently and the numerical overflow of the compressed data can be prevented. It should be possible to compress without any consideration of the upper limit of the compression rate.

In the image data decompression apparatus according to the forty-first aspect, the discontinuous image data is not compressed, and the image data group in which the same image data is continuous includes one of the image data and the continuous number data of the image data. In order to decompress the transferred compressed image data string by replacing the compressed image data string, the storing means replaces the transferred compressed image data string with the image data transferred without replacement. Instead of storing the compressed image data, the replacement means replaces the compressed and transferred image data with the image data string for the continuous number of data, so that the compressed data is not compressed. The image data can be compressed and expanded efficiently without increasing the amount of data. Unisuru.

According to the 46th aspect of the present invention, in the image data decompressing device, the discontinuous image data is not replaced, and the image data group in which the same image data is continuous includes one of the image data and the continuous number data of the image data. In order to decompress the compressed image data sequence that has been compressed and transferred by replacing the transferred compressed image data sequence with the above, the determination means sequentially captures the transferred compressed image data sequence and determines whether the image data can be compressed. The first output unit determines whether or not the image data is determined to be image data that cannot be compressed by the determination unit and outputs the image data as it is. And
The second output means outputs the image data determined to be the image data that can be compressed by the determination means as uncompressed data by outputting the image data corresponding to the continuous number data. On the other hand, the amount of data is not increased so that image data can be compressed and expanded efficiently.

According to the 51st aspect of the present invention, the discontinuous image data is not replaced, and the image data group in which the same image data is continuous is replaced with the image data and the continuous number of the image data. With respect to the compressed image data string that has been compressed and transferred as a result, the image data that has been transferred without replacement is stored as it is without being replaced, and the image data that has been replaced and compressed is the image data. Is replaced with the image data string for the continuous number of data so that the data amount is not increased with respect to the uncompressed data, and the image data can be efficiently compressed / decompressed.

According to the 56th aspect of the present invention, in the image data decompressing device, the discontinuous image data is not replaced, and the image data group in which the same image data is continuous includes one of the image data and a variable length data format of the image data. For the compressed image data string transferred after being replaced with the continuous number data represented by and the length data of the continuous number data, the storage means replaces the image data transferred without being replaced. Instead, the replacement unit replaces the transferred and transferred image data with the image data string for the continuous number of data by referring to the length data, thereby compressing the image data. The decompression can be performed efficiently, and the compression ratio can be increased without considering the numerical overflow of the data to be compressed. To be compressed in the form of free.

According to the 61st aspect of the present invention, in the image data decompressing device, the discontinuous image data is not replaced, and the image data group in which the same image data is continuous includes one of the image data and the variable length data of the image data. In order to expand the compressed image data string that has been compressed and transferred by substituting the continuous number data expressed in the format and the length data of the continuous number data, the determining means is configured to perform the transfer compression. The image data sequence is sequentially fetched to determine whether or not the image data can be a compression target, and the first output unit is an image determined to be an image data that cannot be a compression target by the determination unit. Output the data as it is. Then, the second output means outputs the image data determined by the determination means as image data that can be a target of compression by the continuous number data by referring to the length data, The image data can be compressed / decompressed efficiently and can be compressed without an upper limit of the compression rate without considering the numerical overflow of the compressed data.

According to the 66th aspect of the present invention, in the image data expansion method, the discontinuous image data is not replaced, and the image data group in which the same image data is continuous includes one of the image data and the variable length data of the image data. Regarding the compressed image data string that is compressed and transferred by replacing the continuous number data expressed in the format and the length data of the continuous number data, the image data that is transferred without replacement is not replaced. , The image data transferred after being replaced is replaced with an image data string for the continuous number of data by referring to the length data, whereby the image data can be efficiently compressed / decompressed, In addition, without considering the numerical overflow of the data to be compressed, the compression rate has no upper limit. It can be so.

Compression of image data according to claim 71
In the decompression system, the first storage means stores the discontinuous image data of the transfer target image data string as it is without replacing it, and the first replacement means stores the image data in which the same image data is continuous. The group is replaced with one of the image data and continuous number data of the image data. Then, the second storage unit stores the transferred compressed image data sequence without replacing the transferred image data without replacement, and the second replacement unit replaces the replaced image data with the replaced image data. The transferred image data is replaced with the image data string for the continuous number so that the data amount is not increased with respect to the uncompressed data and the compression / decompression of the image data is efficiently performed. Try to do well.

Compression of image data according to claim 76
In the decompression system, the first discriminating unit sequentially captures the image data string to be transferred and discriminates whether or not the same image data is continuous, and the first output unit is continuously discriminated by the discriminating unit. The image data that is determined not to be output is output as it is, and the counting unit counts the number of consecutive image data that is determined to be continuous by the determination unit, and the second output unit is One of the continuous image data and the continuous number data counted by the counting means are output.

Then, the second discriminating means discriminates whether or not the transferred compressed image data sequence is sequentially taken in and discriminates whether or not the image data can be the object of compression, and the third output means, The image data that has been determined by the determining means to be image data that cannot be compressed is output as is, and the fourth output means is determined to be image data that can be compressed by the determining means. By outputting the image data for the continuous number of data, the amount of image data is not increased with respect to the uncompressed data, so that the image data can be compressed and expanded efficiently.

The compression of image data according to claim 81
In the decompression system, the first storage means stores the discontinuous image data of the transfer target image data string as it is without replacing it, and the first displacement means stores an image in which the same image data is continuous. The data group is replaced with one of the image data, continuous number data of the image data, and length data of the continuous number data.
The second storage unit stores the transferred image data without replacement, without replacing the image data, and the second replacement unit stores the replaced and transferred image data with the length. By referring to the data and replacing it with the image data string for the continuous number of data, the image data can be efficiently compressed / decompressed, and the upper limit of the compression ratio can be achieved without considering the numerical overflow of the data to be compressed. It is possible to compress without any form.

Compression of image data according to claim 86
In the decompression system, the first discriminating unit sequentially captures the image data string to be transferred and discriminates whether or not the same image data is continuous, and the first output unit is continuously discriminated by the discriminating unit. The image data that is determined not to be output is output as it is, and the counting unit counts the number of consecutive image data that is determined to be continuous by the determination unit, and the second output unit is One of the continuous image data, the continuous number data counted by the counting means, and the length data of the continuous number data are output.

The second discriminating means discriminates whether or not the transferred compressed image data sequence is sequentially fetched, and discriminates whether or not the image data can be compressed. The image data that has been determined by the determination means to be image data that cannot be compressed is output as is, and the fourth output means is an image that has been determined to be image data that can be compressed by the determination means. By outputting the data for the continuous number of data with reference to the length data, the image data can be efficiently compressed / decompressed, and the compression rate can be achieved without considering the numerical overflow of the data to be compressed. Allows compression in a form that has no upper limit.

[0049]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An image data compressing device, a decompressing device and the like according to the first and second embodiments of the present invention will be described below with reference to FIGS.

The image data compressing device and decompressing device according to the first and second embodiments are examples applied to a printing system, and the printing system will be described.

This printing system, as shown in FIG.
It has a host device H and a printer device P, which are connected by a cable C. The host device H is C
It has PU1, ROM2 and RAM3, and CPU1
According to the program preset in ROM2,
While using the RAM 3 as a work area, various processes such as data compression described later are performed. An image memory 3a for storing the generated image data is formed in the RAM 3.

Further, the printer device P has a CPU 21, RO
It has an M22 and a RAM 23, and the CPU 21
RAM according to the program preset in M22
While using 23 as a work area, various processes such as data decompression described later are performed. A print memory 23a for storing the image data transferred from the host device H is formed in the RAM 23.

The host device H generates image data to be printed, stores it in the image memory 3a, compresses the data, and transfers it to the printer device P via the cable C.
On the other hand, the printer device P stores the transferred compressed image data in the print memory 23a, sequentially expands the data, and prints. An interface such as parallel or serial is used as the cable C.

[First Embodiment] The first embodiment uses PackB.
Similar to the its encoding method, when the same color data such as white data or black data is continuous, the continuous length (continuous number) is calculated, and the amount (called “counter”) is indicated by 1 byte It is an encoding method that enables compression.

The image data compression / decompression method according to the first embodiment will be described in detail below.

First, the image data compression processing performed by the host device H will be described with reference to the flowchart of FIG. The CPU 1 of the host device H first reads 1-byte image data from the image memory 3a according to the compression processing program preset in the ROM 2 (step S201).

Next, the read image data is "0".
It is determined whether or not it is "0h" (white data) (step S202), and if it is not "00h", it is further determined whether or not it is "FFh" (black data) (step S20).
3). If it is not "FFh", that is, neither "00h" nor "FFh", it means that the same image data is not continuous. Therefore, the read image data is output as it is so as not to be compressed. (Step S204), the process ends. That is, discontinuous image data is output as it is without compression.

When it is determined in step S202 that the read data is "00h", a counter C for counting the continuous number (continuous length) of the same image data.
(Initial state is "0") is incremented by 1 (step S2
05). Then, the next 1-byte image data is read (step S206). It is determined whether the read image data is "00h" (step S20).
7) If it is "00h", it means that "00h" is continuous, so the process returns to step S205, and "00h" is returned.
Continue counting the number of consecutive "h".

On the other hand, if it is not "00h", it means that the continuation of "00h" has been interrupted at this point, so at this point, "00h" should be set to end the compression of "00h".
(1 byte) and the value of the counter C (1 byte), a total of 2 bytes are output (step S208). Then, the counter C is cleared to "0" (step S209), and the process returns to step S203.

When the read data is "FFh" in step S203, the counter C for counting the continuous number of the same image data is incremented by 1 (step S210). Then, the next 1-byte image data is read (step S211). It is determined whether the read image data is "FFh" (step S2).
12), "FFh" means that "FFh" is continuous, so the process returns to step S210 and "Fh" is returned.
Continue counting the number of consecutive "Fh".

On the other hand, if it is not "FFh", it means that the continuation of "FFh" has been interrupted at this point, so at that point, "FFh" should be set so as to end the compression of "FFh".
(1 byte) and the value of the counter C (1 byte), a total of 2 bytes are output (step S213). Then, the counter C is cleared to "0" (step S214), and the process returns to step S202.

As described above, in this embodiment, the data compression is performed only on the continuous image data, and the data compression is not performed on the discontinuous image data. As a result, since the amount of data is not increased with respect to the data that is not compressed, for example, the 20-byte data shown in FIG. 9 could be compressed to 11 bytes in the past, as shown in FIG. As described above, it can be compressed to 10 bytes, and the compression rate can be improved. Therefore, the compressed data generated according to the present embodiment can reduce the data transfer time and the amount of use of the storage device such as a disk. Moreover, it can be easily compressed by software.

Next, the image data decompression process performed by the printer P will be described with reference to the flowchart of FIG. The CPU 21 of the printer device P first follows the decompression processing program preset in the ROM 22.
One-byte image data is read from the print memory 23a (step S301).

Next, the read image data is "0".
0h "(white data) is determined (step S
302), if it is not "00h", it is further determined whether it is "FFh" (black data) (step S303).
If it is not "FFh", that is, even if "00h", "FFh"
If it is not "h", it means that the image data is not compressed, so the read image data is output as it is (step S304), and the process is ended. That is, if it is not the target of expansion, no processing is performed.

When it is determined in step S302 that the read image data is "00h", the next 1-byte data required for the decompression process, that is, the consecutive number of "00h" is read (step S305). . Then, decompression is performed by generating "00h" data for the continuous number, the decompressed image data is output (step S306), and the process ends.

If it is determined in step S303 that the read image data is "FFh", the next 1-byte data required for the decompression process, that is, the consecutive number of "FFh" is read (step S307). . Then, decompression is performed by generating "FFh" data for the continuous number, the decompressed image data is output (step S308), and the process is ended.

As described above, it is possible to easily decompress with software. Moreover, since the compressed data to be expanded is efficiently compressed and the amount of data is reduced, the expansion process can be performed quickly.

[Second Embodiment] The second embodiment uses PackB.
Similar to the its encoding method, when the same color data such as white data “00h” and black data “FFh” are continuous, the continuous length (continuous number) is calculated, and the amount (called “counter”) is calculated. The number of bytes (called "counter length") is 1
It is an encoding method that enables data compression by indicating in bytes and then converting to a form with a counter added.

That is, in the case of image data that can be compressed (white data “00h” or black data “FFh”),
Image data (1 byte) as shown in Fig. 5 (a)
Compressed data is represented by + counter length (1 byte) + counter (number of bytes indicated by counter length: 1 to 256 bytes, initial value is "-1").

The first image data is 1-byte compressed original data of "00h" or "FFh". The counter length indicates the number of bytes of the counter located next. A counter that indicates the number of times image data is repeated (continuous number) has an indefinite length (1 byte at the beginning), and carry is allowed. As a result, a maximum of 256 ^ 256 (256 of 2
A counter that can count up to the 56th power is realized. However,
“00h” of the length counter indicates 256. Also,
The counter is (the number of repetitions of the original data shown at the beginning −
Represents 1).

In the case of uncompressed image data (1 byte data other than white data “00h” and black data “FFh”), it is not subject to compression as shown in FIG. 5B, and image data (1 byte) + Image data (1
(Bytes) + image data (1 byte) + ... The data structure is as it is, and there is no limitation on the data length of uncompressed data.

By constructing the compressed data in this way, it is not necessary to generate the data including the "TAG" again when the "TAG" data overflows as in the conventional compression method. By doing so, it is not necessary to alternately generate "TAG" and 1-byte image data, and the compression efficiency can be improved.

Next, the image data compression processing according to the second embodiment performed by the host device H will be described with reference to the flowchart of FIG. The CPU 1 of the host device H
According to the compression processing program preset in the OM2, first, 1-byte image data is read from the image memory 3a (step S601).

Next, the read image data is "0".
0h "(white data) is determined (step S
602), if it is not "00h", it is further determined whether it is "FFh" (black data) (step S603).
If it is not "FFh", that is, even if "00h", "FFh"
If it is not “h”, it means that the same image data is not continuous. Therefore, the read image data is output as it is so as to be excluded from the compression target (step S6).
04), and ends. That is, the discontinuous image data is output without being compressed.

When it is determined in step S602 that the read data is "00h", the counter C (the initial state is "-1") for counting the continuous number of the same image data is incremented by 1 ( Step S605). At this time, if the counter C has a carry, the counter length C
L is updated (+1) and 1 byte is added as a counter C.

Then, the next 1-byte image data is read (step S606). It is determined whether the read image data is "00h" (step S6).
07), "00h" means that "00h" is continuous, so the process returns to step S205, and "0h" is returned.
Continue counting the number of consecutive "0h".

On the other hand, if it is not "00h", it means that the continuation of "00h" is interrupted at this point, so that the compression of "00h" is finished at that point and "00h" (1 byte) is written. A counter length CL (1 byte) representing the number of bytes required by the counter C and a counter C (the byte length is arbitrary within 1 to 256 bytes) are output (step S608). Then, the counter C is initialized to "-1" and the counter length CL is initialized to "1" (step S609), and the process returns to step S603.

When the read image data is "FFh" in step S603, the counter C for counting the continuous number of the same image data is incremented by 1 (step S610). At this time, if there is a carry in the counter C, the counter length CL is updated (+1) and 1 byte is added as the counter C.

Then, the next 1-byte image data is read (step S611). It is determined whether the read image data is "FFh" (step S6).
12), "FFh" means that "FFh" is continuous, so the process returns to step S610, and "Fh" is returned.
Continue counting the number of consecutive "Fh".

On the other hand, if it is not "FFh", it means that the continuation of "FFh" is interrupted at this point, so that the compression of "FFh" is terminated at that point and "FFh" (1 byte) is written. A counter length CL (1 byte) representing the number of bytes required by the counter C and a counter C (the byte length is arbitrary within 1 to 256 bytes) are output (step S613). Then, the counter C is initialized to "-1" and the counter length is initialized to "1" (step S614), and the process returns to step S602.

As described above, by expressing the continuous number data of the image data in the variable length data format and indicating the data length of the continuous number data, the conventional PackBits
It is possible to solve the problem that the upper limit of the compression ratio and the overflow processing in the encoding method is determined, and the image data can be compressed more efficiently.

Moreover, such image data compression processing can be easily performed by software.
Further, as described above, since the image data can be compressed efficiently, the compressed data generated by this embodiment is
It is possible to shorten the data transfer time and reduce the amount of storage devices such as disks used.

Next, the image data decompression process according to the second embodiment performed by the printer P will be described with reference to the flowchart of FIG. CPU 21 of printer device P
Reads out 1-byte image data from the print memory 23a according to the decompression processing program preset in the ROM 22 (step S701).

Next, the read image data is "00".
h ”(white data) is determined (step S7).
02), if it is not "00h", it is further determined whether it is "FFh" (black data) (step S703).
If it is not "FFh" (also not "00h"), the read data is output as it is because it is not the target of decompression (step S704). That is, if it is not the target of expansion, no processing is performed.

If the result of determination in step S702 is that the read image data is "00h", it is compressed image data and is subject to decompression, so the next 1-byte data required for decompression processing. Is read (step S705). The read 1-byte data is the counter length CL, and the data for the number of bytes indicated by this value is continuously read (step S706).

Then, (00h) data of (the number indicated by the newly read data + 1) is generated (this corresponds to the decompression process), the decompressed data is output (step S707), and the process ends.

If the result of determination in step S703 is that the read image data is "FFh", it is compressed image data and is subject to decompression, so the next 1-byte data required for decompression processing. Is read (step S708). The read 1-byte data is the counter length CL, and the data for the number of bytes indicated by this value is continuously read (step S709).

Then, (FFh) data corresponding to (the number indicated by the newly read data + 1) is generated (this corresponds to the decompression process), the decompressed data is output (step S710), and the process ends.

Thus, also in the second embodiment, it is possible to easily decompress with software. Moreover,
Since the compressed data to be expanded is efficiently compressed and the data amount is reduced, the expansion process can be performed quickly.

FIG. 8 shows an example in which image data is compressed using the processing method of FIG. In FIG. 8, for example, the image data composed of 3 bytes “00h”, “00h”, and “00h” is shown as “00 × 3”.
As shown, for example, as the original image data,
Even if "00h" data continues 100,000 (bytes), it can be compressed to 5 bytes. As can be inferred from this example, the more consecutive "00h" or "FFh" data is, the higher the compression rate is.

The present invention is not limited to the above-described embodiment, and for example, transmission / reception of image data such as a facsimile, a host device and a storage device, a scanner device and a host device, application software and the like. It can be applied to all devices and software to be performed. Also,
The medium to be transferred may be wired or wireless.

[0092]

As described above, according to the present invention,
Data compression is performed only on continuous image data, and data compression is not performed on discontinuous image data, so that the amount of data is not increased with respect to data that is not compressed.
The image data can be compressed and expanded more efficiently than the kBits encoding method.

Further, by expressing the continuous number data of the image data in a variable length data format and indicating the data length of the continuous number data, the upper limit of the overflow process and the compression rate in the conventional PackBits encoding system etc. is determined. By solving the problem, the image data compression / expansion method can be performed more efficiently.

Moreover, such image data compression / expansion processing can be easily performed by software. Further, since the image data can be compressed efficiently as described above, the compressed data generated according to the present invention can reduce the data transfer time and the amount of storage devices such as disks used.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a printing system to which an image data compression device, an expansion device, and the like according to first and second embodiments of the present invention are applied.

FIG. 2 is a flowchart showing a compression process of image data according to the first embodiment of the present invention.

FIG. 3 is a flowchart showing an image data decompression process according to the first embodiment of the present invention.

FIG. 4 is a diagram showing an example of a compression processing result of image data according to the first embodiment of the present invention.

FIG. 5 is a diagram showing a structure of compressed / uncompressed data according to a second embodiment of the present invention.

FIG. 6 is a flowchart showing a compression process of image data according to the second embodiment of the present invention.

FIG. 7 is a flowchart showing image data decompression processing according to the second embodiment of the present invention.

FIG. 8 is a diagram showing an example of a compression processing result of image data according to the second embodiment of the present invention.

[Fig. 9] Fig. 9 is a diagram showing an example of compression of image data by a conventional PackBits encoding method.

FIG. 10 is a diagram showing an example of a conventional decompression processing program.

FIG. 11 is a diagram showing a structure of compressed / uncompressed data according to a conventional PackBits encoding method.

[Explanation of symbols]

 1 ... CPU 2 ... ROM 3 ... RAM 3a ... Image memory 21 ... CPU 22 ... ROM 23 ... RAM 23a ... Print memory H ... Host device P ... Printer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H04N 1/417

Claims (90)

[Claims] 1. A storage unit for storing discontinuous image data in a transfer target image data sequence without replacing the image data, and an image data group in which the same image data is continuous includes one of the image data and a sequence of the image data. An image data compression apparatus, comprising: a replacement unit that replaces the number data. 2. The image data compression apparatus according to claim 1, wherein the image data string to be transferred is an image data string transferred from a host device to a printer device. 3. The image data compressing apparatus according to claim 1, wherein the image data string to be transferred is an image data string transferred for storage in a storage unit in a host device. 4. The image data compression apparatus according to claim 1, wherein the image data string to be transferred is an image data string transferred for transmission and reception between application software. 5. The image data compression apparatus according to claim 1, wherein the image data string to be transferred is an image data string transferred from a scanner device to a host device. 6. A discriminating means for sequentially taking in image data strings to be transferred and discriminating whether or not the same image data is continuous, and the image data discriminated as non-continuous by the discriminating means is outputted as it is. First output means, counting means for counting the number of consecutive image data discriminated as being consecutive by the discriminating means, and one of the consecutive image data counted by the counting means. A second output means for outputting continuous number data, and an image data compression apparatus, comprising: 7. The image data compression apparatus according to claim 6, wherein the image data string to be transferred is an image data string transferred from a host device to a printer device. 8. The image data compression apparatus according to claim 6, wherein the image data string to be transferred is an image data string transferred for storage in a storage unit in a host device. 9. The image data compression apparatus according to claim 6, wherein the image data string to be transferred is an image data string transferred for transmission and reception between application software. 10. The image data string to be transferred is,
7. The image data compression device according to claim 6, wherein the image data sequence is an image data string transferred from the scanner device to the host device. 11. A non-contiguous image data of a transfer target image data string is stored as it is without being replaced, and an image data group in which the same image data is continuous is replaced with one of the image data and a continuous number data. Image data compression method characterized by. 12. The image data string to be transferred comprises:
The image data compression method according to claim 11, wherein the image data string is transferred from the host device to the printer device. 13. The image data string to be transferred comprises:
12. An image data string transferred for storage in storage means in a host device.
Image data compression method described. 14. The image data string to be transferred is,
The image data compressing method according to claim 11, wherein the image data string is an image data string transferred for transmission and reception between application software. 15. The image data string to be transferred comprises:
12. The image data compression method according to claim 11, wherein the image data sequence is an image data string transferred from the scanner device to the host device. 16. An image data sequence to be transferred is sequentially fetched to determine whether or not the same image data is continuous, and the image data determined not to be continuous is output as it is without replacement, and continuous. For the image data group that is determined to be, counting the continuous number,
A method for compressing image data, which comprises replacing and outputting two pieces of data, one of the image data and the continuous number data. 17. The image data string to be transferred is,
17. The image data compression method according to claim 16, wherein the image data string is transferred from the host device to the printer device. 18. The image data string to be transferred comprises:
17. An image data string transferred for storage in storage means in a host device.
Image data compression method described. 19. The image data string to be transferred is
17. The method of compressing image data according to claim 16, wherein the image data string is an image data string transferred for transmission and reception between application software. 20. The image data string to be transferred is,
17. The image data compression method according to claim 16, wherein the image data string is an image data string transferred from the scanner device to the host device. 21. A storage unit for storing discontinuous image data in a transfer target image data string without replacing the image data, and an image data group in which the same image data is continuous is one of the image data and the image data of the image data. An image data compression apparatus comprising: a replacement unit that replaces continuous number data expressed in a variable length data format with length data of the continuous number data. 22. The image data string to be transferred is,
22. The image data compression device according to claim 21, wherein the image data sequence is an image data string transferred from a host device to a printer device. 23. The image data string to be transferred is
22. An image data string transferred for storage in storage means in a host device.
Image data compression device described. 24. The image data string to be transferred is,
22. The image data compressing device according to claim 21, wherein the image data string is an image data string transferred to be exchanged between application software. 25. The image data string to be transferred is,
22. The image data compressing device according to claim 21, wherein the image data string is an image data string transferred from the scanner device to the host device. 26. A discriminating means for sequentially taking in image data strings to be transferred and discriminating whether or not the same image data is continuous, and outputting the image data discriminated as non-continuous by the judging means as it is. First output means, counting means for counting the number of consecutive image data discriminated as being consecutive by the discriminating means, and one of the continuous image data and the counting means for varying. Second output of continuous number data expressed in a long data format and length data of the continuous number data
An image data compression device, comprising: 27. The image data string to be transferred is
27. The image data compressing device according to claim 26, which is an image data string transferred from a host device to a printer device. 28. The image data string to be transferred is,
27. An image data string transferred for storage in a storage means in a host device.
Image data compression device described. 29. The image data string to be transferred is,
27. The image data compression apparatus according to claim 26, which is an image data string transferred to be exchanged between application software. 30. The image data string to be transferred is,
27. The image data compression device according to claim 26, which is an image data string transferred from the scanner device to the host device. 31. The discontinuous image data of an image data string to be transferred is stored as it is without being replaced,
A method of compressing image data, characterized in that an image data group in which the same image data is continuous is replaced with one of the image data, continuous number data expressed in a variable length data format, and length data of the continuous number data. . 32. The image data string to be transferred is,
The image data compression method according to claim 31, wherein the image data string is an image data string transferred from the host device to the printer device. 33. The image data string to be transferred is
32. An image data string transferred for storage in a storage device in a host device.
Image data compression method described. 34. The image data string to be transferred is,
32. The method of compressing image data according to claim 31, wherein the image data string is an image data string transferred for transmission and reception between application software. 35. The image data string to be transferred is,
32. The image data compression method according to claim 31, wherein the image data sequence is an image data string transferred from the scanner device to the host device. 36. A sequence of image data to be transferred is sequentially fetched to determine whether or not the same image data is continuous, and the image data determined to be not continuous is output as it is without replacement, and continuous. For the image data group that is determined to be, counting the continuous number,
A method for compressing image data, which comprises replacing one of the image data, three pieces of continuous number data expressed in a variable-length data format, and three pieces of length data of the continuous number data and outputting the data. 37. The image data string to be transferred is
37. The image data compression method according to claim 36, which is an image data string transferred from a host device to a printer device. 38. The image data string to be transferred is,
37. An image data string transferred for storage in a storage means in a host device.
Image data compression method described. 39. The image data string to be transferred is,
The method of compressing image data according to claim 36, wherein the image data string is an image data string transferred for transmission and reception between application software. 40. The image data string to be transferred is
The image data compression method according to claim 36, which is an image data string transferred from a scanner device to a host device. 41. Discontinuous image data is not replaced, and an image data group in which the same image data is continuous is compressed and transferred by replacing with one of the image data and continuous number data of the image data. An image data decompression device for decompressing a compressed image data string that has been transferred, the storage device storing the transferred compressed image data string as it is without replacing the image data that has been transferred without replacement. The decompressing device for image data, wherein the replaced and transferred image data includes a replacement unit that replaces the image data with an image data string of the continuous number data. 42. The image data decompression device according to claim 41, wherein the compressed image data sequence is transferred from a host device to a printer device. 43. The image data decompression device according to claim 41, wherein the compressed image data sequence is transferred for storage in a storage device in a host device. 44. The image data decompression device according to claim 41, wherein the compressed image data sequence has been transferred to be exchanged between application software. 45. The image data decompression device according to claim 41, wherein the compressed image data sequence is transferred from the scanner device to the host device. 46. The discontinuous image data is not replaced, and an image data group in which the same image data is continuous is compressed and transferred by replacing with one of the image data and the continuous number data of the image data. An image data decompressing device for decompressing the compressed image data sequence that has been received, and a determination unit that determines whether or not the transferred compressed image data sequence is image data that can be subject to compression by being sequentially captured, First output means for directly outputting the image data which has been determined to be image data that cannot be compressed by the determination means, and image data which has been determined to be image data that can be compressed by the determination means Is a second output device that outputs the image data corresponding to the continuous number data. An image data decompressing device, characterized by comprising steps and. 47. The image data decompression device according to claim 46, wherein the compressed image data sequence is transferred from a host device to a printer device. 48. The image data decompression device according to claim 46, wherein the compressed image data string has been transferred for storage in a storage device in a host device. 49. The image data decompression apparatus according to claim 46, wherein the compressed image data string is transferred for transmission and reception between application software. 50. The image data decompression device according to claim 46, wherein the compressed image data sequence is transferred from the scanner device to the host device. 51. Discontinuous image data is not replaced, and an image data group in which the same image data is continuous is compressed and transferred by replacing with one of the image data and continuous number data of the image data. For the compressed image data sequence that has been transferred, the image data that has been transferred without replacement is stored without replacement, and the image data that has been transferred after replacement has the image data corresponding to the continuous number of data. A method for decompressing image data, characterized by replacing with a data string. 52. The image data decompression method according to claim 51, wherein the compressed image data string is transferred from the host device to the printer device. 53. The image data decompression method according to claim 51, wherein the compressed image data sequence is transferred for storage in a storage unit in a host device. 54. The method of decompressing image data according to claim 51, wherein the compressed image data string is transferred for transfer between application software. 55. The method of decompressing image data according to claim 51, wherein the compressed image data string is transferred from the scanner device to the host device. 56. An image data group in which the same image data is continuous without replacing the discontinuous image data is one of the image data, continuous number data represented in a variable length data format of the image data, and the continuous image data. Regarding the compressed image data string transferred after being replaced with the length data of the number data, the storage means for storing the image data transferred without replacement as it is without replacement, and the replacement after transfer An image data decompression device, comprising: a replacement unit that replaces the received image data with an image data string of the continuous number data by referring to the length data. 57. The decompression method of image data according to claim 56, wherein the compressed image data string is transferred from the host device to the printer device. 58. The method of decompressing image data according to claim 56, wherein the compressed image data string has been transferred for storage in a storage device in a host device. 59. The method of decompressing image data according to claim 56, wherein the compressed image data string is transferred to be exchanged between application software. 60. The image data decompression method according to claim 56, wherein the compressed image data string is transferred from the scanner device to the host device. 61. An image data group in which the same image data is continuous without replacing the discontinuous image data is one of the image data, a continuous number data represented in a variable length data format of the image data, and the continuous image data. An image data decompression device for decompressing a compressed image data sequence that has been compressed and transferred by substituting length data for number data, and is a target for compression by sequentially fetching the transferred compressed image data sequence. Discriminating means for discriminating whether or not the image data can be the image data, first output means for directly outputting the image data discriminated as the image data which cannot be compressed by the discriminating means, and the judging means. The image data determined to be image data that can be compressed by An image data decompression device comprising: a second output unit that refers to the data and outputs only the continuous number data. 62. The image data decompression device according to claim 61, wherein the compressed image data string is transferred from a host device to a printer device. 63. The image data decompression device according to claim 61, wherein the compressed image data sequence is transferred for storage in a storage device in a host device. 64. The image data decompression device according to claim 61, wherein the compressed image data sequence has been transferred to be exchanged between application software. 65. The decompression device for image data according to claim 61, wherein the compressed image data string is transferred from the scanner device to the host device. 66. An image data group in which the discontinuous image data is not replaced and the same image data is continuous includes one of the image data, continuous number data represented in a variable length data format of the image data, and the continuous image data. Regarding the compressed image data string that has been compressed and transferred by replacing it with the length data of the number data, the image data that has been transferred without replacement is stored as it is without being replaced, and the image data that has been replaced is transferred. A method for decompressing image data, wherein the received image data is replaced with an image data string for the continuous number of data by referring to the length data. 67. The image data decompression method according to claim 66, wherein said compressed image data string is transferred from a host device to a printer device. 68. The method of decompressing image data according to claim 66, wherein the compressed image data string has been transferred for storage in a storage device in a host device. 69. The method of decompressing image data according to claim 66, wherein the compressed image data string has been transferred to be exchanged between application software. 70. The image data decompression method according to claim 66, wherein the compressed image data string is transferred from the scanner device to the host device. 71. A first storage means for storing discontinuous image data in a transfer target image data string as it is without replacing it, and an image data group in which the same image data is continuous is regarded as one of the image data. First replacing means for replacing the image data with the continuous number data, second storing means for storing the image data transferred without replacement, and the transferred data after replacement. An image data compression / expansion system, wherein the image data comprises second replacement means for replacing the image data with an image data string for the continuous number of data. 72. The image data string to be transferred is
The image data compression / expansion system according to claim 71, which is an image data string transferred from a host device to a printer device. 73. The image data string to be transferred is
72. An image data string transferred for storage in storage means in a host device.
Image data compression / decompression system described. 74. The image data string to be transferred is,
72. The image data compression / expansion system according to claim 71, wherein the image data string is an image data string transferred for transmission and reception between application software. 75. The image data string to be transferred is,
72. The image data compression / expansion system according to claim 71, which is an image data string transferred from the scanner device to the host device. 76. First discriminating means for sequentially taking in image data strings to be transferred and discriminating whether or not the same image data is continuous; and image data discriminated by the discriminating means as not being continuous. Is output as it is, a counting means for counting the number of consecutive image data discriminated as being continuous by the discriminating means, and one of the continuous image data and the counting means. Second output means for outputting the counted continuous number data, and image data that can be a target for compression by sequentially taking in the compressed image data strings output and transferred from the first and second output means. A second discriminating unit for discriminating whether or not there is an image; and an image discriminated by the discriminating unit as image data that cannot be compressed. Third output means for outputting the data as it is, and third output means for outputting the image data for which the determination is made by the determination means as the image data that can be compressed, by the continuous number data. An image data compression / expansion system characterized by having and. 77. The image data string to be transferred is
77. The image data compression / decompression system according to claim 76, which is an image data string transferred from a host device to a printer device. 78. The image data string to be transferred is,
77. An image data string transferred for storage in a storage device in a host device.
Image data compression / decompression system described. 79. The image data string to be transferred is
77. The image data compression / decompression system according to claim 76, which is an image data string transferred for transfer between application software. 80. The image data string to be transferred is,
77. The image data compression / expansion system according to claim 76, which is an image data string transferred from the scanner device to the host device. 81. A first storage unit for storing discontinuous image data of an image data string to be transferred as it is without replacing the image data, and an image data group in which the same image data is continuous is regarded as one of the image data. First replacing means for replacing the continuous number data of the image data with length data of the continuous number data; and second storing means for storing the image data transferred without replacement without replacing the image data. A second replacing unit that replaces the replaced and transferred image data with an image data string corresponding to the continuous number data by referring to the length data. Compression / expansion system. 82. The image data string to be transferred is
The image data compression / expansion system according to claim 81, which is an image data string transferred from the host device to the printer device. 83. The image data string to be transferred is
81. An image data string transferred for storage in a storage device in a host device.
Image data compression / decompression system described. 84. The image data string to be transferred is,
The image data compression / expansion system according to claim 81, which is an image data string transferred for transfer between application software. 85. The image data string to be transferred is,
The image data compression / decompression system according to claim 81, which is an image data string transferred from the scanner device to the host device. 86. First discriminating means for sequentially taking in image data strings to be transferred and discriminating whether or not the same image data is continuous; and image data discriminated as non-continuous by the discriminating means. Is output as it is, a counting means for counting the number of consecutive image data discriminated as being continuous by the discriminating means, and one of the continuous image data and the counting means. Second output means for outputting the counted continuous number data and the length data of the continuous number data, and sequentially taking in the compressed image data string outputted and transferred from the first and second output means. Second discriminating means for discriminating whether or not the image data can be a compression target, and an image which cannot be a compression target by the discriminating means. Third output means for outputting the image data determined to be data as it is, and image data determined to be image data that can be compressed by the determination means by referring to the length data and the continuous data. An image data compression / expansion system comprising: a fourth output means for outputting only the number data. 87. The image data string to be transferred is
87. The image data compression / expansion system according to claim 86, which is an image data string transferred from a host device to a printer device. 88. The image data string to be transferred is,
87. The image data string transferred for storage in the storage means in the host device.
Image data compression / decompression system described. 89. The image data string to be transferred is,
87. The image data compression / expansion system according to claim 86, which is an image data string transferred for transfer between application software. 90. The image data string to be transferred is,
87. The image data compression / decompression system according to claim 86, which is an image data sequence transferred from the scanner device to the host device.