JP2002051221A - Device, system and method for encoding and decoding image and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To change an encoding parameter for each block without the designation of a user by encoding each of blocks while using the encoding parameter based on flag data showing an attribute for each block and to perform decoding while using a decoding parameter for each block when decoding each of blocks. SOLUTION: In a step S901, the attribute of a tile is judged on the basis of inputted attribute flag data and when a character is contained in the tile, a quantizing matrix is set to M1. When no character is contained, on the other hand, the quantizing matrix is set to M2. In a step S903, the tile is quantized while using the set quantizing matrix.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image coding apparatus for dividing image data into blocks having a predetermined size and coding the blocks, and a block included in a data structure input from the outside. Encoded image data for each, an image decoding device for decoding the encoding flag data,
The present invention relates to a system including the image encoding device and the image decoding device, a method thereof, and a storage medium.

[0002]

2. Description of the Related Art Conventionally, compression methods for color still images include:
JPEG method using discrete cosine transform, Wave
A method using let conversion is often used. In this type of coding system, basically, the entire image is uniformly encoded. Therefore, when the coding system is changed for each partial region of the image, a region for identifying the region is separately provided. I need information.

The purpose of dividing the area is to coarsen the quantization step of a photographic area where image quality deterioration is relatively inconspicuous, and to finely quantize a character area where image quality deterioration is relatively inconspicuous.

Similarly, by discriminating between a natural image portion and a computer graphics portion, a quantization step for a natural image region where image quality degradation is relatively inconspicuous is coarsened, and a computer graphics region where image quality degradation is relatively inconspicuous is quantized. The finer things were conceived.

[0005]

However, the area information for switching the quantization step is processed by the user designating a rectangular area using some kind of designating means, or by automatically cutting out the rectangular area where the photograph data exists. In other words, switching can be performed only in a relatively large area unit.

The present invention has been made in view of the above-mentioned conventional problems, and encodes each block using an encoding parameter based on flag data indicating an attribute of each block, thereby enabling a user to specify It is an object of the present invention to provide an image coding apparatus that changes a coding parameter for each block without any change.

It is another object of the present invention to provide an image decoding apparatus for decoding each block using a decoding parameter for each block.

[0008]

In order to achieve the object of the present invention, for example, an image coding apparatus of the present invention has the following arrangement. That is, an image coding apparatus that divides image data into blocks having a predetermined size and performs coding on the blocks, wherein the image data and flag data corresponding to each pixel of the image data are input. Inputting means, storage and holding means for storing and holding a plurality of encoding parameters, generating means for generating flag data representative of each block based on flag data corresponding to each pixel of the image data, When encoding, based on the flag data representing the block of interest generated by the generating means, selecting means for selecting one of the encoding parameters from the storage and holding means, The encoding process is performed on the image data of the block of interest by using the Performs coding processing on Gudeta, to form a data structure including the coded image data and coded flag data, and outputs to the outside.

In order to achieve the object of the present invention, for example, an image decoding apparatus of the present invention has the following arrangement. That is, an image decoding apparatus that decodes encoded image data for each block and encoding flag data included in a data structure input from the outside, based on specific data included in the data structure. Means for specifying a decoding parameter, and output means for outputting image data decoded using the decoding parameter specified by the specifying means as an image.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail according to preferred embodiments with reference to the accompanying drawings.

[First Embodiment] FIG. 1 is a schematic configuration of a system including an image encoding apparatus for encoding an image and an image decoding apparatus for decoding an encoded image according to the present embodiment. It is a block diagram showing, using the figure,
This will be described below. In the figure, reference numeral 100 denotes an image input system (image scanner unit 150, page description language (hereinafter, PDL))
Selector for switching the rendering unit 151), 101
Reference numeral denotes a compression block line buffer for storing image data and attribute flag data input from the image input system determined by switching by the selector 100.

Reference numeral 102 denotes an attribute flag data encoding unit that encodes attribute flag data, and reference numeral 120 denotes a determination unit that determines a control method of an image encoding process in the image encoding unit 103 based on the attribute flag data.

Here, the attribute flag data encoding unit 102
Unlike the image encoding unit described below, well-known lossless encoding such as run-length encoding (so-called lossless encoding) is performed so that the attribute flag data after decoding becomes the same as that at the time of input.

[0014] 103 is based on the result of the determination unit 120,
An image encoding unit that encodes image data stored in the compression block line buffer 101; 104, encoded image data (encoded image data); encoded attribute flag data (encoded attribute Flag data).

Reference numeral 105 denotes an HDD (hard disk drive) as an external storage device for storing the encoded image data and the encoding attribute flag data stored in the compression memory 104; This is a compression memory for reading and storing flag data, and may be the same as the compression memory of 104.

Reference numeral 107 denotes an attribute flag data decoding unit for decoding the encoded attribute flag data. Reference numeral 121 denotes an image decoding unit in the image decoding unit 108 based on the attribute flag data decoded by the attribute flag data decoding unit 107. It is a determination unit that determines a control method of the conversion process.

108 is based on the result of the determination unit 121,
An image decoding unit that decodes the encoded image data stored in the compression memory 106.

Reference numeral 109 denotes an expansion block buffer for storing the image data decoded by the image decoding unit 108. Reference numeral 110 denotes an I / F with a printer or the like as an image generation unit (not shown).

The encoding process performed by the system according to the present embodiment having the above configuration will be described with reference to FIG. 7 which shows a flowchart of the encoding process. The program code according to the flowchart shown in the figure is stored in a memory such as a ROM or a RAM (not shown) of the system of the present embodiment, and is read and executed by a CPU (not shown).

First, attribute flag data is input together with image data from the image input system selected by the selector 100 (step S701).

As described above, the image input system includes 150 image scanners and 151 PDL rendering units. From 150 for a copier, to 1 for a printer.
The selectors of 100 are switched and used depending on the use, such as from 51. The image scanner unit 150 includes a well-known image area separation processing unit. For example, attribute flag data for identifying pixels constituting a black character portion in a document image can be generated in pixel units. Also, P of 151
The DL rendering unit interprets the PDL command to generate a print image. At this time, referring to the information indicating the type of the command, an attribute for identifying the pixels constituting the black character pixel as in the scanner unit 150 The flag data is generated for each pixel.

Here, the attribute flag data is not limited to data indicating a black character. For example, multi-bit information indicating various attributes such as a color character area, a halftone area, a vector graphics area, and the like is used as the attribute flag data. Can be used.

Next, the compressed block line buffer 101
The input image is divided into tiles (step S70).
2) The discrete cosine transform coding (JPEG), which is the coding of color information, is performed by the image coding unit 103 for each of the M × N pixels (assuming the tile size is M × N). Is performed by the attribute flag data encoding unit 102 (steps S703 and S704).

However, M and N must be multiples of the window size for discrete cosine transform coding. In the JPEG compression method used in the present embodiment, the window size for compression is 8 × 8 pixels, so for example, M = N =
Assuming 32, the 32 × 32 pixel tile is further divided into 16 8 × 8 pixels, and JPEG compression is performed in units of 8 × 8 pixels. (Hereinafter, the description will be made assuming that M = N = 32, but the value is of course not limited to this value.) The image encoding unit 103 calculates 16 8 × 8 pixel windows included in the tile image of 32 × 32 pixels. Well-known D
It is subjected to CT transformation and quantized. The quantization coefficient (called a quantization matrix) used at this time can be switched and set for each tile by a method described later. The attribute flag data is used as the switching signal, and is input to the attribute flag data encoding unit 102. Therefore, the encoding of the attribute flag data is performed at least after the encoding of the image data. And 32 × 3 corresponding to the image data
Referring to the attribute flag data of the two pixels, the determination unit 120 performs a determination process described later, generates a quantization coefficient selection signal, and sends it to the image encoding unit 103.

FIG. 9 is a flowchart of the quantization process in the image data encoding process of step S703.
And a specific process in the quantization process will be described. It is assumed that the processing according to the flowchart shown in FIG. 9 is performed for each tile.

In step S901, the determining unit 120 determines the attribute of the tile based on the input attribute flag data. Here, the attribute flag data is attached to each pixel. However, in the present embodiment, since the encoding method in the tile is fixed, the attribute flag data in the tile is analyzed by the determination unit 120, and the tile Is determined. Therefore, a quantization matrix corresponding to the attribute representing this tile is selected.

In this embodiment, when determining the attribute of a tile, it is determined whether or not a character is included in the tile.
If a character is included in the tile, the process proceeds to S902,
Set the quantization matrix to M1. On the other hand, if not included, the process shifts to step S904 to set the quantization matrix to M2. In step S901, in this embodiment, it is determined whether or not the attribute of the tile includes a character, and two quantization matrices are prepared in advance in each case. However, the present invention is not limited to this. For example, the attributes of tiles are determined in three stages (regions including characters, regions including graphics, and regions including photographic images), and three quantization matrices are prepared in advance according to each case. May be.

In step S903, the tile is quantized using the set quantization matrix.

As described above, the encoding process for the image data including the quantization process according to the flowchart shown in FIG. 9 is performed in step S703, and encoded image data is generated.

Next, the encoded image data and the encoded attribute flag data are transferred to the HDD 10 via the compression memory 104.
5 are stored as compressed image data and compression attribute flag data, respectively (step S705).

FIG. 4 is a flowchart showing a process for outputting encoded image data stored in the HDD 105 to a device such as an external printer via the image generation unit 110 as a decoded image. 8 will be described. Note that, like the program code according to the flowchart illustrated in FIG. 7, the program code according to the flowchart illustrated in FIG. 7 is stored in a memory such as a ROM or a RAM (not illustrated) included in the system according to the present embodiment. It is read and executed by the CPU.

First, data of M × N pixels of the encoded attribute flag data stored in the HDD 105 is read and decoded by the attribute flag data decoding unit 107 (step S801).

Next, the image decoding unit 108 decodes the image data by switching the decoding parameter (in this embodiment, the inverse quantization matrix) of the encoded image data based on the decoded attribute flag data (step S802). ), And decodes the decoded image data into a block buffer 109 for expansion.
Is output and stored (step S803).

At this time, first, in the decoded attribute flag data, the attribute flag data in M × N pixels is subjected to analysis and determination processing equivalent to that of the determination unit 120 by the determination unit 121. A decoding unit 107 sets and decodes an inverse quantization matrix for decoding M × N pixel image data to be decoded.

FIG. 10 shows a flowchart of the inverse quantization processing (the processing performed by switching the decoding parameters in the above description) in the decoding processing of the encoded image data in step S802, and a specific processing in the inverse quantization will be described. I do. The processing according to the flowchart shown in FIG. 10 is also performed for each tile (in the encoded image data), similarly to the processing shown in FIG.

In step S1001, as described above, the determination unit 121 performs the same analysis and determination processing as the determination unit 120 based on the attribute flag data. If the tile includes a character, the process proceeds to step S1002. An inverse quantization matrix N1 is set. On the other hand, if not included, the process shifts to step S1004 to set the inverse quantization matrix N2.

In step S1003, the tiles are subjected to inverse quantization using the set inverse quantization matrix.

As described above, the decoding process for the encoded image data including the inverse quantization process according to the flowchart shown in FIG. 10 is performed in step S802, and the image data is restored.

As described above, the determination unit 120 and the determination unit 121 make exactly the same determination, and the attribute flag data is compressed by a lossless compression method such as run-length encoding without data deterioration. The determination results based on the attribute flag data corresponding to the same tile at the time of encoding and at the time of decoding are completely equal. Therefore, even if quantization is performed with a different quantization coefficient for each tile, an inverse quantization coefficient corresponding to each tile is set at the time of decoding, so that the same image data as the image data before decoding can be obtained. Become.

FIG. 2 is a block diagram showing a schematic configuration of the image encoding unit 103 and the image decoding unit 108 according to the processing flow with the memory 15 for temporarily storing encoded image data interposed therebetween.

Reference numeral 200 denotes an image signal (image data) input from the above-mentioned image input system, and in the case of a color signal, three colors of red (R), green (G), and blue (B), 256 gradations Signal.

A color converter 11 converts an image signal 200 (for example, an RGB signal) into a luminance / color difference signal (YCbCr).

Reference numeral 12 denotes a discrete cosine transform (DCT) unit.
A spatial frequency transform (DCT transform) is performed on each of the luminance and chrominance signals in units of 8 × 8 pixels to generate DCT coefficients.

Numeral 13 denotes a quantizer which quantizes the DCT coefficient by the DCT unit 12 using a set quantization matrix (generates a quantized value), thereby reducing the data amount of the DCT coefficient.

A variable length encoder (VLC) 14 performs a Huffman encoding process on the quantized value (generates encoded image data) to further reduce the data amount of the quantized value.

The above is the schematic configuration of the image encoding unit 103, and the encoded image data is stored in the memory 15. The memory 15 corresponds to the HDD 105 in FIG. 1, for example.

Next, the schematic configuration of the image decoding unit 108 will be described.

A variable length decoder (VLD) 16 performs Huffman decoding on the coded image data and converts the coded image data into a quantized value.

Reference numeral 17 denotes an inverse quantizer which uses the set inverse quantization matrix to convert the restored quantized value into a DC value.
Restore the T coefficient value.

Reference numeral 18 denotes an IDCT unit which performs inverse DCT on the DCT coefficient value to restore a luminance / color difference signal.

Reference numeral 19 denotes a color converter for converting the luminance / color difference signals into RGB signals.
Return to signal.

Reference numeral 201 denotes a color image signal finally output from the image decoding unit 108,
Same as 0.

FIG. 3 is a diagram showing a schematic configuration of the attribute flag data encoding unit 102 that performs run-length encoding on attribute flag data as described above.

The determination section 310 determines whether the value of the previous pixel and the value of the current pixel corresponding to the input attribute flag data are the same, and if they are the same, the RL code generation section 311 is generated. The unit 312 is switched to send attribute flag data.

The RL code generation section 311 counts the number of times of the same case as the previous pixel data until different data comes out, and finally outputs the repeated data.

The LT part code generation 312 counts the number of cases where the data is different from the previous pixel, and outputs the code word corresponding to the count and the minimum number of constituent bits of the actual data by the count.

In the combining section 313, the RL code generating section 31
1 and the output data of the LT code generation unit 312 are combined and output as a code 315.

Here, a method of switching the quantization matrix by the attribute flag data will be described.

FIG. 4A shows an example of a document image in which a photograph area and a character area are mixed, and shows the configuration of the entire page. FIG. 4B shows attribute flag data generated for this document image, and here shows that only a character area is extracted.

FIG. 4C is a diagram showing a state in which the entire original image is divided into tiles of M × N pixels (in the present embodiment) 32 pixels × 32 pixels. Here, a quantization matrix can be set for each tile.

FIG. 4D shows an example in which the attribute is character and the tile is divided into tiles including the character and tiles not including the character by referring to the attribute flag data shown in FIG. 4B. In this drawing, the tiles indicated by the oblique lines are identified as tiles that do not include characters.

Here, it is determined whether or not a character is included in a tile. Pixels constituting even one pixel in a 32 × 32 pixel tile (attribute flag data whose attribute is a character) Is included, it can be determined that the character is included.Alternatively, if the number of pixels of the attribute flag data whose attribute is character is counted in the tile and exceeds a predetermined threshold, this tile is It can also be determined that the tile is a tile including.

When identification is performed as shown in FIG. 4D, different quantization matrices are set for tiles including characters and tiles not including characters, and image data is encoded.

FIG. 5 is an example of a quantization matrix for DCT coefficients of 8 × 8 pixels. FIG. 9A is an example of a quantization matrix T1 applied to a photograph area not including characters, and FIG. 9B is an example of a quantization matrix T2 applied to a tile including characters (shown in FIG. 9). The quantization matrices M1 and M2 in the flowchart correspond to T2 and T1, respectively.)

Normally, the upper left of the matrix is the quantization step for the DC component, and the quantization step for the high frequency component is shown toward the right or below. The smaller the numerical value is, the smaller the quantization step is, that is, the information of the original image is stored. T2 is set such that the numerical value in the upper left area is larger than T1, and the numerical value becomes smaller toward the right or downward. That is, the information of the high frequency component is stored while slightly sacrificing the low frequency component, so that the compression deterioration of the character image can be reduced.

When decoding the compressed data, first, the compressed attribute flag data is decoded, and the number of pixels of the character attribute in the tile is counted in the same manner as described above to determine whether or not the tile is a character area. If determined, an inverse quantization matrix (corresponding to N1 or N2 in the flowchart shown in FIG. 10) corresponding to T1 and T2 is set and decoding is performed.

In the above, the quantization matrices T1, T2
The inverse quantization matrices corresponding thereto are stored in advance in the quantization unit 13 and the inverse quantization unit 17 in FIG. 2, and the determination units 120 and 121 determine which to use according to the attribute of the image data, and Switch by unit.

As described above, the image coding apparatus and the image processing method according to the present embodiment can control the quantization for each local area of the image according to the attribute of the image, and can control the deterioration of the image quality due to the compression. .

In this embodiment, the program code according to the processing shown in FIGS. 7 to 10 is stored in a memory (not shown) inside the system, but the present invention is not limited to this. That is, the program code according to the flowchart of the process for encoding the image shown in FIGS. 7 and 9 is stored in a memory such as a ROM or a RAM (not shown) in the image encoding device, and is stored in FIGS. The program code according to the flowchart of the process for decoding the encoded image shown is stored in a memory such as a ROM or a RAM (not shown) in the image decoding device, and the CPU in each device is Alternatively, the program code may be read from the memory and executed.

The system according to the present embodiment operates as described above. In FIG. 1, image data attribute flags are input from the image scanner unit 150 or the page description language rendering unit 151, and these are encoded and stored in the HDD.
A device (image coding device) that inputs coded image data to the HDD 105 and a device (image decoding device) that reads coded image data from the HDD 105 and outputs the image data to the image generation unit 110 may be a single device. Operation is clear from the above description.

[Second Embodiment] In the first embodiment, the configuration in which the setting of the quantization matrix and the setting of the inverse quantization matrix are always switched with reference to the attribute flag data has been described. When decoding image data, it is necessary to decode attribute flag data first,
In addition, it is necessary to provide blocks for counting image area information in both the quantization unit and the inverse quantization unit.

Therefore, in the present embodiment, the image encoding unit 103
, The code information indicating which of the T1 and T2 quantization matrices is used by the quantizer 13 is stored in the header of each tile of the encoded image data.

When decoding the image data compressed in this way, only the header portion is referred to, and the inverse quantization matrix is specified based on the code specifying the used quantization matrix described in the header. Can be switched, so that it is not necessary to refer to the attribute flag data information.

FIG. 6 is a conceptual diagram showing the data structure when the encoded image data and the encoded attribute flag data are stored in the HDD 105. Header information of the first tile, DCT-coded image information, and run-length-coded attribute flag information are stored in order from the beginning of the data, and the second and third tiles have the same configuration. , And the information up to the last tile included in the entire page is written.

The header information of each tile records the data size of the compressed data, the tile number, and the like. At the same time, information for specifying whether T1 or T2 is used as the quantization matrix of the image data is also stored. be written.

Therefore, when decoding the coded image data which has been coded and recorded, the header information is referred to
What is necessary is just to read the information of T1 or T2, select the inverse quantization matrix corresponding to each, and execute the inverse quantization.

Therefore, the flowchart of the processing of the system according to the present embodiment is different from the flowcharts shown in FIGS. 7 to 10 in that step S1001 in FIG. 10 is performed when encoded image data is generated with reference to the above-mentioned header information. It is a flowchart in which it is specified whether the used quantization matrix is T1 or T2.

[Other Embodiments] Even if the present invention is applied to a system composed of a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), an apparatus (one device) For example, the present invention may be applied to a copying machine, a facsimile machine, and the like.

Further, an object of the present invention is to supply a storage medium (or a recording medium) in which a program code of software for realizing the functions of the above-described embodiments is recorded to a system or an apparatus, and a computer (a computer) of the system or the apparatus. It is needless to say that the present invention can also be achieved by a CPU or an MPU) reading and executing the program code stored in the storage medium. In this case, the program code itself read from the storage medium implements the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention. Also,
When the computer executes the readout program code, not only the functions of the above-described embodiments are realized, but also the operating system (OS) running on the computer based on the instructions of the program code.
It goes without saying that a case where the functions of the above-described embodiments are implemented by performing some or all of the actual processing, and the processing performs the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written in a memory provided in a function expansion card inserted into the computer or a function expansion unit connected to the computer, the program code is read based on the instruction of the program code. Needless to say, the CPU included in the function expansion card or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

When the present invention is applied to the storage medium, the storage medium includes the storage medium described above (shown in FIGS. 7 to 10).
The program code corresponding to the flowchart is stored.

[0082]

As described above, according to the present invention, each block is coded by using a coding parameter based on flag data indicating an attribute of each block, thereby enabling coding without user designation. Parameters can be changed for each block.

When decoding each block, decoding can be performed using the decoding parameter for each block.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a system according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a schematic configuration of an image encoding unit 103 and an image decoding unit 108 according to a processing flow, with a memory 15 for temporarily storing encoded image data interposed therebetween.

FIG. 3 is a diagram showing a schematic configuration of an attribute flag data encoding unit 102.

4A is a diagram illustrating an example of a document image in which a photograph area and a character area are mixed, and FIG. 4B is a diagram illustrating attribute flag data generated for the document image illustrated in FIG. Diagram,
(C) is a view showing a state in which the entire original image is divided into tiles of 32 pixels × 32 pixels, and (d) is a table in which the attribute is a character by referring to the attribute flag data shown in (c). It is a figure which shows the example divided | segmented into the tile which does not include this character, and the tile which does not contain it.

FIG. 5 is an example of a quantization matrix for DCT coefficients of 8 × 8 pixels.

FIG. 6 is a conceptual diagram showing a data structure when coded image data and coded attribute flag data are stored in an HDD 105.

FIG. 7 is a flowchart of an encoding process performed by the system according to the first embodiment of the present invention.

FIG. 8 is a flowchart of a process when outputting encoded image data stored in the HDD 105 to a device such as an external printer via the image generation unit 110 as a decoded image.

FIG. 9 is a flowchart of a quantization process in the image data encoding process in step S703.

FIG. 10 is a flowchart of an inverse quantization process in the decoding process of the encoded image data in step S802.

Continued on front page F-term (reference) 5C059 MA23 MC14 ME05 PP01 PP15 PP20 RC11 RC40 SS15 SS20 SS28 TA47 TA53 TB08 TC00 TC02 TC06 UA02 UA05 5C078 AA09 BA57 CA02 DB07 5J064 AA01 BA08 BA09 BA13 BA15 BA16 BC01 BC02 BC14 BC25 BD03 BD07

Claims (16)

[Claims] 1. An image encoding apparatus which divides image data into blocks having a predetermined size and encodes the blocks, wherein the image data and a flag corresponding to each pixel of the image data are provided. Input means for inputting data, storage and holding means for storing and holding a plurality of encoding parameters, and generating means for generating flag data representing each block based on flag data corresponding to each pixel of the image data. Selecting a coding parameter from the storage unit based on the flag data representing the block of interest generated by the generating unit when coding the block of interest; The encoding process is performed on the image data of the block of interest using the encoding parameter selected by The performs encoding processing on the flag data, forming a data structure including the coded image data and coded flag data, the picture coding apparatus and outputs to the outside. 2. The image encoding apparatus according to claim 1, wherein the input unit includes an image scanner and a unit that renders a page description language. 3. The image coding apparatus according to claim 1, wherein the coding includes a discrete cosine transform. 4. The image coding apparatus according to claim 1, wherein the coding parameter includes a quantization coefficient. 5. The image according to claim 1, wherein the predetermined data structure further includes a code for specifying an encoding parameter selected by the selection unit. Coded storage. 6. The flag data corresponding to each pixel of the image data indicates an attribute of each pixel of the image data, and the flag data representative of each block by the generation unit includes:
The image encoding apparatus according to claim 1, wherein an attribute of each block is indicated. 7. An image decoding apparatus for decoding coded image data for each block and coded flag data included in a data structure input from the outside, wherein a specific code included in the data structure is included. Based on the data,
An image decoding device, comprising: a specifying unit that specifies a decoding parameter; and an output unit that outputs image data decoded using the decoding parameter specified by the specifying unit as an image. 8. The specific data includes a code for specifying an encoding parameter used when the encoded image data is encoded, and the identifying unit includes a decoding parameter based on the code. The image decoding apparatus according to claim 7, wherein 9. The method according to claim 7, wherein the specifying unit specifies a decoding parameter based on flag data obtained as a result of decoding the encoded flag data.
5. The image decoding device according to claim 1. 10. The method according to claim 7, wherein the decoding parameter includes an inverse quantization coefficient.
Item 7. The image decoding device according to Item 1. 11. An image decoding apparatus according to claim 7, wherein said output means includes a printer. 12. An image encoding device that divides image data into blocks having a predetermined size and encodes the blocks, and a block for each block included in a data structure input from the image encoding device. And a picture decoding apparatus for decoding the coding flag data, wherein the picture coding apparatus comprises: a flag corresponding to each of the image data and each pixel of the picture data. Input means for inputting data, storage and holding means for storing and holding a plurality of encoding parameters, and generating means for generating flag data representing each block based on flag data corresponding to each pixel of the image data. When encoding the block of interest, based on the flag data representative of the block of interest generated by the generation unit, Selecting means for selecting one of the coding parameters, performing coding processing on the image data of the block of interest using the coding parameter selected by the selecting means, and setting flag data of the block of interest. To form a data structure including encoded image data and encoding flag data, the image decoding device, based on the specific data included in the data structure,
A system comprising: a specifying unit that specifies a decoding parameter; and an output unit that outputs, as an image, image data decoded using the decoding parameter specified by the specifying unit. 13. An image encoding method for dividing image data into blocks having a predetermined size and encoding the blocks, wherein the image data and a flag corresponding to each pixel of the image data are provided. An input step of inputting data to a predetermined input unit; a storage and holding step of storing and holding a plurality of encoding parameters in a predetermined storage and holding unit; and each block based on flag data corresponding to each pixel of the image data. Generating a flag data representing the target block; and, when encoding the block of interest, encoding parameters from the predetermined storage unit based on the flag data representing the block of interest generated in the generation step. A selecting step of selecting one, and using the encoding parameter selected in the selecting step, the image data of the block of interest is Performs coding processing and performs encoding processing with respect to the flag data of the block of interest,
An image coding method comprising forming a data structure including coded image data and coding flag data, and outputting the data structure to the outside. 14. An image decoding step of decoding coded image data for each block and coded flag data included in a data structure input from the outside, wherein a specific code included in the data structure is included. Based on the data,
An image comprising: a specifying step of specifying a decoding parameter; and an output step of outputting image data decoded using the decoding parameter specified by the specifying step to a predetermined output unit as an image. Decryption method. When encoding the block of interest, a selection step of selecting one encoding parameter from the predetermined storage unit based on the flag data representing the block of interest generated in the generation step, and encoding the block of interest. A selecting step of selecting one encoding parameter from the predetermined storage unit based on the flag data representing the block of interest generated in the generating step. 15. A storage medium storing a program code that functions as an image encoding device that divides image data into blocks having a predetermined size and performs encoding on the blocks. A program code of an input step of inputting flag data corresponding to each pixel of the image data to a predetermined input unit; a program code of a storage holding step of storing a plurality of encoding parameters in a predetermined storage unit; Based on the flag data corresponding to each pixel of the image data, a program code of a generation step of generating flag data representative of each block, and, when encoding the block of interest, the block of interest generated by the generation step Based on the representative flag data, one encoding parameter is selected from the predetermined storage unit. A program code for the selecting step, performing encoding processing on the image data of the block of interest using the encoding parameter selected in the selecting step, and encoding the flag data of the block of interest. A storage medium for performing a process, forming a data structure including coded image data and coded flag data, and outputting the data structure to the outside. 16. A storage medium for storing coded image data for each block and a program code functioning as an image decoding device for decoding coded flag data, which are included in a data structure input from outside. Based on the specific data included in the data structure,
A program code for a specific step for specifying a decoding parameter; and a program code for an output step for outputting image data decoded using the decoding parameter specified in the specifying step to a predetermined output unit as an image. A storage medium characterized by the above-mentioned.