JP3075935B2 - Still image coding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a still image encoding method for compressing information of a still image using an encoding method, and which requires a still image information compression process such as a facsimile or an electronic still camera. Can be used for

[0002]

2. Description of the Related Art Encoding methods often used as techniques for efficiently compressing still images include MH, MR, MMR and JBIG if the images are all characters, and JPEG if all images are natural images. .

[0003] However, if an attempt is made to compress a mixed image of a natural image and characters by the above-described JPEG, JBIG and other encoding methods, the encoding efficiency in the natural image portion is low in MH, MR, MMR and JBIG. Become. JPE
In G, mainly the high frequency component data is deleted, so that the outline of the character is blurred.

[0004] An encoding method for improving those methods is introduced in a paper (Shirasawa, Imao, Yamada: "Adaptive encoding method of mixed images of characters and pictures", 1991, 22nd Image Engineering Conference). In addition, the mixed image is separated into image areas such as a natural image part and a character part, and compressed by an encoding method suitable for the natural image part and the character part in the encoding processing, and each code is encoded in the decoding processing. There is known a technique of decompressing an image by decompressing the image by a decoding method performed in the processing and combining the images.

[0005]

However, in the above-mentioned conventional encoding method, the MH, MR, MMR,
Since a plurality of code data such as JBIG and JPEG are generated, handling of the code data is very inconvenient. Also,
A large amount of memory is required when synthesizing the decoded image data, resulting in a cost burden, and when decoding and displaying the image data, it is displayed in separate image units, which makes it visually difficult to see. There was something.

Accordingly, the present invention has been made in view of the above, and has made it easier to handle code data.
It is an object of the present invention to provide a still image encoding method capable of reducing a required memory amount and further improving display.

[0007]

A still image encoding method according to claim 1 divides one still image into a plurality of images, further divides the plurality of separated images into images of a predetermined data unit, The divided images are encoded by an encoding method suitable for each image, and each code data created thereby is used as a unit, and these are regularly assembled to create one code data.

[0008] A still image encoding method according to a second aspect comprises:
One still image is separated into a plurality of images, and the separated plurality of images are further divided into images in units of a fixed number of lines, and the divided images are encoded by an encoding method suitable for each image, Each of the created code data is used as a unit, and these are assembled in the sub-scanning direction to create one code data.

A still image encoding method according to a third aspect of the present invention comprises:
One still image is divided into a plurality of images, the plurality of separated images are further divided into images in units of a fixed resolution, and the divided images are encoded by an encoding method suitable for each image, thereby being created. Each of the obtained code data is used as a unit, and these are assembled in the order of the low resolution to create one code data.

[0010] A still image encoding method according to claim 4 is as follows.
One still image is divided into a plurality of images, the plurality of separated images are further divided into images in units of a fixed amount, and the divided images are encoded by an encoding method suitable for each image. Each of the created code data is used as a unit, and these are assembled in the sub-scanning direction to create one code data.

[0011] A still picture encoding method according to claim 5 is as follows.
One still image is separated into a plurality of images, and the separated plurality of images are coded by a coding method suitable for each image, and each code data created thereby is used as a unit. One code data is created.

[0012] The still picture encoding method according to claim 6 comprises:
One still image is separated into a plurality of images, and the separated plurality of images are coded by a coding method suitable for each image, and each coded data generated thereby is further divided into a predetermined data unit. It is divided into code data, and the code data is regularly assembled to create one code data.

[0013] A still image encoding method according to claim 7 is as follows.
One still image is separated into a plurality of images, and the separated plurality of images are coded by a coding method suitable for each image. , And assembles the code data in the sub-scanning direction to create one code data.

[0014]

According to the first aspect, one still image is divided into a plurality of images, the plurality of separated images are further divided into images of a predetermined data unit, and the divided images are encoded by a code suitable for each image. New code data can be generated by encoding the data in accordance with the conversion scheme, using each of the code data generated thereby as a unit, and assembling them regularly.

According to a second aspect of the present invention, one still image is divided into a plurality of images, and the plurality of separated images are further divided into images of a fixed number of lines, and the divided images are suitable for each image. One new code data can be created by encoding the data by the encoding method and assembling each of the created code data in the sub-scanning direction.

According to a third aspect of the present invention, one still image is divided into a plurality of images, the plurality of separated images are further divided into images of a fixed resolution unit, and the divided images are encoded by a code suitable for each image. New code data can be generated by encoding the data in accordance with the conversion method, and assembling the code data generated thereby as a unit, in ascending order of resolution.

According to a fourth aspect of the present invention, one still image is divided into a plurality of images, and the plurality of separated images are further divided into images in units of a fixed ratio, and the divided images are suitable for each image. One new code data can be created by encoding the data by the encoding method and assembling each of the created code data in the sub-scanning direction.

According to a fifth aspect of the present invention, one still image is separated into a plurality of images, and the plurality of separated images are coded by a coding method suitable for each image. By assembling as a unit, one code data can be created.

According to a sixth aspect of the present invention, one still image is separated into a plurality of images, and the plurality of separated images are coded by a coding method suitable for each image. In contrast, by further dividing into code data of a predetermined data unit and assembling the code data regularly, it is possible to create one new code data.

According to a seventh aspect of the present invention, one still image is separated into a plurality of images, and the plurality of separated images are coded by a coding method suitable for each image, and each coded data generated by the coding is generated. In contrast, one code data can be created by further dividing the code data into units of a fixed code amount and assembling the code data in the sub-scanning direction.

[0021]

Next, a still picture encoding method according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a hardware configuration diagram for realizing a still image encoding method according to an embodiment of the present invention.

In the present embodiment, an image in which a natural image and characters are mixed, which is a general mixed image, will be described.

In FIG. 1, 1 is an input section for inputting an image, 2 is an output section for outputting an image, 3 is a memory for temporarily holding certain input image data in an encoding process, and a predetermined data in a decoding process. A block line memory unit for temporarily holding output image data decoded for each unit;
Is a separation processing unit that separates a mixed image into images such as a natural image portion and a character portion in the encoding process, and 5 is an image in a predetermined number of data units that is separated and expanded into a natural image portion and a character portion in the decoding process. The synthesizing processing unit 6 performs the coding of the image of the natural image portion divided into the image of a predetermined number of data in the encoding process by the main control unit 11 described later, and the decoding process described later in the decoding process. A JPEG processing unit that decodes JPEG code data divided into predetermined data units input from a division processing unit 9 that performs a decoding operation. The image of the divided character portion is encoded, and in the decoding process, JBIG code data divided into predetermined data units input from the division processing unit 9 described later is decoded. A BIG processing unit 8 is a combining processing unit that combines the respective coded data output by the JPEG processing unit 6 and the JBIG processing unit 7 in units of a predetermined number of data in the encoding process in units of a predetermined number of data. A division processing unit that divides combined code data AiBi (see FIG. 6 described later), which is combined in a predetermined number of data units input from the memory unit 10, into JPEG code data Ai and JBIG code data Bi. The code memory unit to be held, 11 is an input unit 1, an output unit 2, a block line memory unit 3, a separation processing unit 4, a synthesis processing unit 5,
JPEG processing unit 6, JBIG processing unit 7, combining processing unit 8,
The main control unit controls the division processing unit 9, the code memory unit 10, and the like.

First, an outline of the encoding process will be described with reference to FIG.

FIG. 2 is a schematic flowchart of an encoding process in the still image encoding method according to the embodiment of the present invention, which is program-controlled by the main control unit 11.

First, in step S 1, a fixed amount of original image formed of a natural image and characters is read by the input unit 1 and stored in the block line memory unit 3.

In step S2, the original image stored in the block line memory unit 3 in step S1 is sent to the separation processing unit 4 and separated into a natural image portion, a character portion, and the like. (Not shown).

In step S3 or step S4, the main controller 11 reads only a predetermined number of data units of image data from the natural image portion original image and the character portion original image stored in step S2. And stored in a memory (not shown) managed by the JBIG processing unit 7.

In step S5, the natural image portion original image data stored in the memory managed by the JPEG processing section 6 in units of a predetermined number of data in step S3 is JPEG-encoded, and in step S7 the predetermined image generated in step S5 is generated. The JPEG code data in units of data is stored in a memory (not shown) managed by the JPEG processing unit 6.

In step S6, the character part original image data stored in the memory managed by the JBIG processing unit 7 in the predetermined number of data units in step S4 is subjected to the JBIG encoding process. JBIG code data of a predetermined number of data units
It is stored in a memory (not shown) managed by the processing unit 7.

In step S9, the JP stored in units of a predetermined number of data in steps S7 and S8
The EG code data and the JBIG code data are combined by the combination processing unit 8, and the combined code data that has been subjected to the encoding process and the combining process in units of a predetermined number of data in step S 10 is stored in the code memory unit 10.

Here, although not described in FIG. 2,
Since the unit of the original image reading process in step S1 is a certain fixed amount, if image data for one screen cannot be read, steps S1 to S10 are performed until reading of image data for one screen is completed. It is necessary to perform the processing a plurality of times, so that the encoded data of each screen is sequentially combined and stored in the code memory unit 10 in step S10 in the order of creation in order to generate code data for one screen. Keep it.

In the above-described embodiment, the processing for dividing the data into units of a predetermined number of data is performed in steps S3 and S4.
Has been performed using the counter of the main control unit 11, but the present invention is not limited to this.
The present invention is also applicable to a case where the main control unit 11 divides the code data generated by the encoding processing by the PEG processing unit 6 and the JBIG processing unit 7 into a predetermined number of data units and outputs the divided data to the combination processing unit 8. Still image coding method can be realized.

At this time, in the encoding process, JPE
The G processing unit 6 and the JBIG processing unit 7 do not encode the natural image part image and the character part image that are divided and input by the main control unit 11 in units of a predetermined number of data from the separation processing unit 4 as described above. Then, the image data of a certain fixed number of data input from the separation processing unit 4 is encoded, and then the generated code data is divided by the main control unit 11 into units of a predetermined number of data. Output to

In the above-described embodiment, the data is divided by a predetermined number of data. However, if the data is not divided, the JPEG processing unit 6 and the JPEG
The BIG processing unit 7 does not encode the natural image part image and the character part image divided and input by the predetermined number of data units from the separation processing unit 4 by the main control unit 11 as described above. , The image data for one screen is input at a time, and then the generated code data is output to the combination processing unit 8 without division.

Here, the combining process in the embodiment of the present invention will be described in detail with reference to FIGS. 3 (a) and 3 (b).

FIG. 3A is a processing diagram in the combination processing unit 8 of the present invention.

FIG. 3B is a processing diagram for performing processing for sequentially combining the combined code data AiBi combined in a predetermined data unit in the combining processing unit 8 in the code memory unit 10 and combining the combined code data AiBi into one screen of code data AB. is there.

In FIG. 3A, reference numerals 21 and 22 denote JP.
The JPEG code data Ai and the JBIG code data Bi in predetermined data units output from the EG processing unit 6 and the JBIG processing unit 7 are combined code data 23 obtained by combining the JPEG code data Ai and the JBIG code data Bi.
iBi.

In FIG. 3 (b), reference numeral 24 is already in FIG.
Combined code data AB that is regularly assembled and combined by the combined code data AiBi according to the method (b),
Reference numeral 25 denotes combined code data AiBi in FIG. 3A combined by the combining processing unit 8, and reference numeral 26 designates combined processing of the combined code data 24 and 25 by the method shown in FIG. This is combined code data AB.

(1) When the division unit is a fixed number of lines, JPEG divided by a fixed number of lines in the sub-scanning direction
The combined code data AiBi23 is created by combining the code data Ai21 and the JBIG code data Bi22, and the combined code data AiBi23 is further combined in the sub-scanning direction to create combined code data AB26 for one screen.
This is an embodiment according to claim 2.

(2) When the division unit is a fixed resolution, JPEG code data Ai21 and JBIG code data Bi22 divided at a fixed resolution in the order of lower resolution are combined to create combined code data AiBi23. AiBi23 is further combined in the order of lower resolution to create combined code data AB26 for one screen. This is an embodiment according to claim 3.

(3) When the division unit is a fixed rate, the JPEG code data Ai21 and the JBIG code data Bi22 divided by the fixed rate in the sub-scanning direction are combined to create combined code data AiBi23. The combined code data AiBi23 is further combined in the sub-scanning direction to create combined image data AB26 for one screen. This is an embodiment according to claim 4.

(4) When the division is not performed, the JPEG code data Ai21 and the JBIG code data Bi22 are combined in units of code data to create combined code data AB26. This is an embodiment corresponding to claim 5, which corresponds to the special case of claim 2.

(5) When the division unit is a fixed code amount, JPEG code data Ai21 and JBIG code data Bi22 divided by a constant code amount in the sub-scanning direction are combined to create combined code data AiBi23. The combined code data AiBi23 is further combined in the sub-scanning direction to create combined image data AB26 for one screen. This is an embodiment of the present invention.

Here, assuming that the code data 21 and 22 are variable-length codes, the delimiter between the code data and the code data cannot be recognized if they are combined as they are. Therefore, in order to clarify the delimiter between the code data Ai and the code data Bi, it is necessary to add data serving as a mark by some method. The method will be described with reference to FIG.

FIG. 4A is a diagram showing a combined code data structure in which a header is added to the head of all the code data constituting the combined code data AB created in the embodiment of the present invention.
FIG. 4B shows the combined code data A according to the embodiment of the present invention.
FIG. 9 is a diagram showing a combined code data structure when a header is added only to the head of B.

In FIG. 4A, the combined code data AB
Are encoded and added to the beginning of all the code data that constitutes the code data, such as the coding method and the code data length.

In FIG. 4B, the combined code data A
Code data information such as a coding method and a code data length of all the code data constituting B are collectively added to the head of the combined code data AB and combined.

Here, the header adding method will be described. When a header is added to all the code data constituting the combined code data AB as shown in FIG. 4 (a), the JPEG processing unit 6 and the JBIG processing unit 7 create the data by the main control unit 11 after the coding is completed. A header of each code data is added to the head of each code data, and FIG.
When the header is added only to the head of the combined code data AB as in (b), the main control unit 11 transmits the combined code data AB temporarily stored in the memory in the main control unit 11.
The header information of each code data, which is a component of the above, is combined into one header, and this is added to the head of the combined code data AB stored in the code memory unit 10. By adding a header in this manner, the delimiter between the code data Ai and the code data Bi becomes clear, and the division process in the decoding process can be executed without error.

In this embodiment, the code data Ai
A1, B1, A2, B
2,..., AN, BN,
.., N are fixed in order, but the order of combining code data A and code data B is arbitrary.
, B2, A2,..., BN, AN, A1, B1,.
B2, A2,..., AN, BN may be used.

Next, an outline of the decoding process will be described with reference to FIG.

FIG. 5 is a schematic flowchart of a decoding process in the still image encoding method according to the embodiment of the present invention, which is program-controlled by the main control unit 11.

In FIG. 5, in step S31, the header of the combined code data AB stored in the code memory unit 10 is analyzed, and the combined code data AB is constructed based on the analyzed encoding method and encoded data length. One set of the combined code data AiBi is read and output to the division processing unit 9.

In step S 32, the division processing section 9 sets the combined code data A inputted from the code memory section 10.
The iBi is divided into JPEG code data Ai and JBIG code data Bi based on the header information analyzed in step S31, and stored in a memory (not shown) managed by the division processing unit 9.

In steps S33 and S34,
JPEG coded data Ai divided in step S32
(Not shown) for managing the JBIG code data Bi by the JPEG processing unit 6 and the JBIG processing unit 7, respectively.
To be stored.

In step S35, the JPEG code data Ai in the predetermined data unit stored in step S33 is subjected to JPEG decoding by the JPEG processing unit 6, and in step S37, the natural image portion image decoded in step S35 is decoded. Is stored in a memory (not shown) managed by the JPEG processing unit 6.

In step S36, step S3
In step S38, the JBIG processing unit 7 performs JBIG decoding on the JBIG code data Bi in the predetermined data unit stored in step 4, and in step S38, the JBIG processing unit 7 manages the character part image decoded in step S36. (Not shown).

In step 39, the natural image portion image and the character portion image in a predetermined data unit stored in step S37 and step S38 are synthesized into a mixed image by the synthesis processing section 5,
It is stored in the block line memory unit 3, and the process proceeds to step S
At 40, the output unit 2 outputs the mixed image data in a predetermined data unit stored in the block line memory unit 3,
Obtain the decoded image.

Although not described in FIG. 5,
In the combined code data reading process of step S31, since the unit to be read is a set of combined code data AiBi constituting the combined code data AB, if the code data for one screen cannot be read, the code data for one screen is read. It is necessary to perform the processing from step S31 to step S40 a plurality of times until the reading of the image data is completed.
0, it is added that image data for one screen can be output by sequentially outputting.

Here, the division processing in the embodiment of the present invention will be described in detail with reference to FIGS. 6 (a) and 6 (b).

FIG. 6A is a processing diagram for dividing the combined code data AB stored in the code memory unit 10 into combined code data AiBi in units of a predetermined number of data.

FIG. 6B is a processing diagram in the division processing section 9 of the present invention.

In FIG. 6A, reference numeral 51 denotes combined code data AB stored in the code memory unit 10;
Is the code data AiBi extracted from the combined code data AB based on the analysis of the header of the combined code data AB and the analyzed encoding method and the encoded data length.
Is the remaining combined code data AB. Note that this division process is a process of dividing the combined code data AB stored in the code memory unit 10 in units of combination in order from the beginning.

In FIG. 6B, reference numeral 54 denotes the i-th combined code data obtained by dividing the combined code data AB in order from the beginning of the combined code data AB in FIG. I-th JPE divided by the division processing by
G code data Ai and JBIG code data Bi.

(1) When the unit of connection is a fixed number of lines,
From the combined code data AB51 to the combined code data AiBi5
4 is read and is divided into code data Ai55 and code data Bi56 for a fixed number of lines, which is a unit of connection. As a result, each process after the division process can also be performed in units of a fixed number of lines, so that it is only necessary to prepare memories for the fixed number of lines. In addition, the image can be sequentially displayed by dividing and expanding the image in the sub-scanning direction.

(2) When the combination unit has a fixed resolution, the combination code data AB51 to the combination code data AiBi54
Is read and divided into code data Ai55 and code data Bi56 for a fixed resolution, which is a unit of connection. Accordingly, each process after the division process can be performed in a unit of a fixed resolution. In addition, it is possible to display progressively by dividing and decompressing in units of a certain resolution.

(3) When the combination unit has a fixed ratio, the combination code data AB51 to the combination code data AiBi54
Is read and divided into a fixed ratio of code data Ai55 and code data Bi56, which are the unit of connection. As a result, each process after the division process can also be processed in units of a fixed ratio, so that it is only necessary to prepare a memory for the fixed ratio. In addition, the image can be sequentially displayed by dividing and expanding the image in the sub-scanning direction.

(4) When the combination unit is a code unit, all the combined code data AB51 are read, and this is divided into code data Ai55 and code data Bi56 in a code data unit which is a combination unit. At this time, normal code data may be decoded.

(5) When the combination unit has a fixed code amount, the combination code data AB51 to the combination code data AiBi54
Is read and divided into code data Ai55 and code data Bi56 having a fixed code amount as a unit of connection. As a result, each process after the division process can also be processed in units of a fixed code amount, so that it is only necessary to prepare a memory for the fixed code amount. In addition, the image can be sequentially displayed by dividing and expanding the image in the sub-scanning direction.

As described above, in the present embodiment, in encoding, one still image is divided into a plurality of images, and the plurality of separated images are encoded by an encoding method suitable for each image. A plurality of pieces of code data further divided into predetermined data units can be combined into one piece of code data for each piece of the obtained code data, and one still image is separated into a plurality of images, and the separated Can be further divided into images of a predetermined data unit, and a plurality of code data obtained by encoding the divided images by an encoding method suitable for each image can be combined into one code data. A still image is separated into a plurality of images, and the code data obtained by coding the separated images by a coding method suitable for each image is divided into a plurality of code data. Can Mel, thereby is facilitated handling of the code data.

Further, when the unit of connection is a fixed number of lines, a fixed code amount, and a fixed ratio, the unit of code data is not a single screen unit but a small code amount unit. Encoding and decoding can be performed with an image memory and a code memory having smaller capacities than when encoding is performed.
In the case where the unit of connection is a fixed number of lines, a fixed resolution, a fixed code amount, and a fixed ratio amount, an image area for alternately expanding and displaying a natural image portion and a character portion for each combined code data,
Since the character areas can be displayed almost simultaneously, it is easy to see.

The embodiments of the present invention have been described on the assumption that the above (1) to (5) are provided independently of each other. However, when the present invention is implemented, the above (1) to (5) will be described. It is more effective to prepare the processing method of (1) and select the most suitable processing.

[0075]

As described above, in the still image encoding method according to the first aspect, one still image is separated into a plurality of images, and the separated plurality of images are further divided into images of a predetermined data unit. Since the divided images are encoded by an encoding method suitable for each image, and each of the encoded code data is regularly assembled to form one code data, one still image is generated. A plurality of code data is divided into a plurality of images, the separated image is further divided into images of a predetermined unit, and a plurality of code data is generated by compressing the image by a coding method suitable for each image. It can be combined into one code data, and the handling of the code data becomes easy.

When the unit of connection is a fixed number of lines and a fixed ratio, the unit of code data is not a single screen unit but a small code amount unit. The encoding and decoding processes can be performed with a smaller-capacity image memory and code memory, and the encoding and decoding apparatus can be less expensive. In particular, since the process of dividing the image into a predetermined unit is performed by the main control unit between the separation processing unit and the JPEG processing unit and between the separation processing unit and the JBIG processing unit, the memory managed by the JPEG processing unit and the JBIG processing unit is , The capacity of a predetermined unit to be divided is sufficient. When the unit of connection is a fixed number of lines, a fixed resolution, and a fixed amount, the image area and the character area can be displayed almost simultaneously, so that it is easy to see.

According to the still image encoding method of the present invention, one still image is divided into a plurality of images, and the plurality of separated images are further divided into images of a fixed number of lines. Since each encoded image is encoded by an encoding method suitable for each image and each encoded data is assembled in the sub-scanning direction to generate one encoded data, one still image is separated into a plurality of images. Then, the separated image is further divided into a predetermined unit of image, and a plurality of code data are created by compressing the image by a coding method suitable for each image. They can be put together and the handling of the code data can be facilitated.

Also, since the unit of code data is not a single screen unit but a small code amount unit, the coding data can be encoded with a smaller capacity image memory and code memory than when encoding and decoding are performed in a single screen unit. And the decoding process can be performed, and the apparatus for encoding and decoding becomes inexpensive. In particular, since the process of dividing the image into units of a fixed number of lines is performed by the main control unit between the separation processing unit and the JPEG processing unit and between the separation processing unit and the JBIG processing unit 7, the JPEG processing unit and the JBIG processing unit manage the image. The memory to be divided may have a capacity corresponding to a certain number of divided lines. Since the image area and the character area can be displayed almost simultaneously, it is easy to see. In the case of decoding, each process of the division process shift can also be processed in units of a fixed number of lines, so that it is only necessary to prepare memory for a fixed number of lines. In addition, the image can be sequentially displayed by dividing and expanding the image in the sub-scanning direction.

In the still picture encoding method of the present invention, one still picture is divided into a plurality of pictures, and the plurality of separated pictures are further divided into pictures of a unit of a fixed resolution. Is encoded by an encoding method suitable for an image, and each encoded data is assembled in order of low resolution to create one encoded data, so that one still image is separated into a plurality of images, Dividing the separated image into images of a predetermined unit and compressing a plurality of code data into one code data for a plurality of code data created by compressing the image by an encoding method suitable for each image. And it is easy to handle the code data.

Further, since the image area and the character area can be displayed almost simultaneously, it is easy to see. In the case of decoding, each process after the division process can also be processed in units of a fixed resolution. In addition, it can be displayed progressively by decompressing in units of a fixed resolution.

In the still picture encoding method according to the fourth aspect, one still picture is divided into a plurality of pictures, and the plurality of separated pictures are further divided into pictures in a unit of a fixed ratio. Since each encoded image is encoded by an encoding method suitable for each image and each encoded data is assembled in the sub-scanning direction to generate one encoded data, one still image is separated into a plurality of images. Then, the separated image is further divided into a predetermined unit of image, and a plurality of code data are created by compressing the image by a coding method suitable for each image. They can be put together and the handling of the code data can be facilitated.

Further, since the unit of code data is not a single screen unit but a small code amount unit, it is possible to perform encoding using a small-capacity image memory and code memory as compared with the case of performing encoding and decoding in one screen unit. And the decoding process can be performed, and the apparatus for encoding and decoding becomes inexpensive. In particular, since the main control unit performs the process of dividing the image into units of a fixed amount between the separation processing unit and the JPEG processing unit and between the separation processing unit and the JBIG processing unit, the JPEG processing unit and the JBIG processing unit manage the processing. The memory may be of a fixed percentage capacity to be divided. Since the image area and the character area can be displayed almost simultaneously, it is easy to see. In the case of decoding, each process after the division process can also be processed in a fixed ratio unit, so that it is only necessary to prepare a memory for a fixed ratio amount. In addition, the image can be sequentially displayed by dividing and expanding the image in the sub-scanning direction.

In the still picture encoding method according to the fifth aspect, one still picture is separated into a plurality of pictures, and the plurality of separated pictures are coded by a coding method suitable for each picture and coded. In this case, a single still image is separated into a plurality of images, and a plurality of images are created by compressing the images by a coding method suitable for each image. , A plurality of code data can be combined into one code data, and it is easy to handle the code data. In the case of decoding, decoding may be performed in a normal code data unit.

In the still image encoding method according to the sixth aspect, one still image is divided into a plurality of images, and the plurality of separated images are encoded by an encoding method suitable for each image, and are encoded. Each code data is further divided into code data of a predetermined data unit, and the code data is regularly assembled to generate one code data. Therefore, one still image is converted into a plurality of images. Encode the separated images using an encoding method suitable for each image,
A plurality of code data can be combined into one code data for a plurality of code data created by further dividing each encoded data into code data of a predetermined data unit. Data handling becomes easier.

Further, when the combination unit is a fixed code amount, the unit of code data is not a single screen unit but a small code amount unit. Encoding and decoding processes can be performed with a large-capacity image memory and code memory, and the cost of the encoding and decoding apparatus is reduced. When the combination unit has a fixed code amount, the image area and the character area can be displayed almost simultaneously, so that it is easy to see.

[0086] Regarding the processing speed, since the division processing is performed after the generation of the code data, the operation of transferring the image data from the division processing section to the JPEG processing section is performed even if the JPEG encoding is in progress. If there is free space in the memory managed by the processing unit, the JPEG processing unit and JB
The data can be transferred to the memory managed by the IG processing unit at any time, and the processing speed is increased.

In the still picture encoding method of the present invention, one still picture is separated into a plurality of pictures, and the plurality of separated pictures are coded by a coding method suitable for each picture, and are coded. Each code data is further divided into code data in units of a fixed code amount, and the code data is assembled in the sub-scanning direction to create one code data. A plurality of code data created by coding an image separated into images by a coding method suitable for each image, and further dividing each of the coded code data into code data of a predetermined data unit. In contrast, a plurality of code data can be combined into one code data, and the handling of the code data can be facilitated.

Further, since the unit of code data is not a single screen unit but a small code amount unit, it is possible to perform encoding using a smaller capacity image memory and code memory than when encoding and decoding are performed in one screen unit. And the decoding process can be performed, and the apparatus for encoding and decoding becomes inexpensive. Since the image area and the character area can be displayed almost simultaneously, it is easy to see. In the case of decoding, each process subsequent to the division process can also be processed in a fixed code amount unit, so that it is only necessary to prepare a memory for a fixed code amount. Also,
By dividing and expanding in the sub-scanning direction, display can be performed sequentially.

Since the division processing is performed after the generation of the code data with respect to the processing speed, the image data transfer operation from the division processing section to the JPEG processing section is performed even if the JPEG encoding is in progress. If there is free space in the memory managed by the processing unit, the JPEG processing unit and JB
The data can be transferred to the memory managed by the IG processing unit at any time, and the processing speed is increased.

[Brief description of the drawings]

FIG. 1 is a hardware configuration diagram for realizing a still image encoding method according to an embodiment of the present invention.

FIG. 2 is a schematic flowchart of an encoding process in a still image encoding method according to an embodiment of the present invention.

FIG. 3A is an explanatory diagram of the combination in the combination processing unit of the present invention, and FIG. 3B is a code memory unit for combining code data AiBi combined in a predetermined data unit in one screen by the code memory unit; FIG. 9 is an explanatory diagram of a combining process for performing a combining process on code data AB.

FIG. 4A is a diagram showing a combined code data structure when a header is added to the head of all divided code data in the embodiment of the present invention, and FIG. 4B is a diagram in which a header is added only to the head of the combined code data. FIG. 6 is a diagram showing the configuration of combined code data when it is set.

FIG. 5 is a schematic flowchart of a decoding process in the still image encoding method according to the embodiment of the present invention.

FIG. 6A is an explanatory view of division processing for dividing the combined code data AB stored in the code data section into combined code data AiBi in units of a predetermined number of data, and FIG. 6B is a division processing section of the present invention. It is explanatory drawing of division | segmentation in.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Input part 2 Output part 3 Block line memory part 4 Separation processing part 5 Synthesis processing part 6 JPEG processing part 7 JBIG processing part 8 Coupling processing part 9 Separation processing part 10 Code memory part 11 Main control part

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-144485 (JP, A) JP-A-6-3344872 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04N 1/41-1/419 H04N 7/24-7/68

Claims (7)

(57) [Claims] 1. A single still image is separated into a plurality of images, the plurality of separated images are further divided into images of a predetermined data unit, and the divided images are encoded by an encoding method suitable for each image. A still image encoding method characterized by regularly assembling and encoding each encoded data to form one encoded data. 2. The method according to claim 1, wherein the predetermined data unit is a unit of a fixed number of lines, and each piece of code data encoded by an encoding method is assembled in a sub-scanning direction to create one piece of code data. Still picture encoding method. 3. The code data according to claim 1, wherein the predetermined data unit is a fixed resolution unit, and each code data coded by a coding method is assembled in order of low resolution to form one code data. Still image coding method. 4. The method according to claim 1, wherein the predetermined data unit is a fixed ratio unit, and each code data encoded by an encoding method is assembled in a sub-scanning direction to generate one code data. Still picture encoding method. 5. A single still image is separated into a plurality of images, the plurality of separated images are coded by a coding method suitable for each image, and each coded code data is assembled to form one code. A still image encoding method comprising creating encoded data. 6. A single still image is separated into a plurality of images, and the plurality of separated images are coded by a coding method suitable for each image. 1. A still image encoding method, comprising dividing code data into units of code data and regularly assembling the code data divided into predetermined data units to generate one code data. 7. The code data unit according to claim 6, wherein the predetermined data unit is a fixed code amount unit, and the code data divided into the fixed code amount unit is assembled in the sub-scanning direction to generate one code data. Still image encoding method.