JP2003078767A - Image processing method and apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image processing method and apparatus by which encoding of an image with a better efficiency can be performed in encoding image data in which an area of a basic image is changed. SOLUTION: This invention provides the image processing method and apparatus for generating an image whose prescribed area is changed and encoding the image, a tile division section 102 divides a basic image into a plurality of tiles, a tile classification section 103 classifies the tiles into common tiles whose contents include no change areas subjected to contents change and change tiles including the revision areas, and first and second buffers 104, 105 store them respectively. A tile data encoding section 108 encodes image data of the common tiles and the first buffer 104 stores the encoded data, difference image data are attached (106) to the image data of the revision tiles stored in the second buffer 105 to obtain changed image data, the tile data encoding section 108 encodes the data to generate i-th derivative image encoded data in combination with the encoded image data of the common tiles. The processing above is executed for number of times corresponding to number of kinds of difference image data to generate a plurality of kinds of derivative images depending on number of kinds of the difference image data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing method and apparatus for encoding image data in which a predetermined area of image data of a basic image is changed.

[0002]

2. Description of the Related Art In recent years, with the spread of personal computers and mobile terminals, digital data communication (data communication) via the Internet has been widely performed. Still image data is a typical digital data distributed in this data communication. Since such still image data has a large data amount, it is usually encoded in advance to suppress the data amount of the still image data to be small at the time of transmission or storage. As a method of encoding such still image data, for example, ISO / iEC109
18-1 | iTU-TT. 81, JPEG
There is an encoding method. In this JPEG encoding method, a series of image data is converted by discrete cosine conversion.

At present, the discrete wavelet transform is drawing attention as a method for transforming a series of image data. This is because the decoded image of the image coded data generated by the discrete wavelet transform and the decoded image of the image coded data generated by the discrete wavelet transform tend to produce less noise. This is because there is an advantage.

Further, by encoding the image by the discrete wavelet transform, it is possible to perform a stepwise display (progressive display) of the decoded image so that the fineness and resolution of the decoded image are improved as the decoding progresses. become. With such a progressive display, a viewer who receives and views a still image can know rough information of the image at an early stage of receiving or decoding the image.

There are various possible applications of such image data encoded by the discrete wavelet transform capable of progressive display. One of them is the distribution of information from companies to customers according to the capacity of the communication line and the resolution of the data display device on the receiving side. In this information distribution, a company may send information to a large number of customers that has a partial area (changed area) that should be changed for each customer (FIGS. 2A to 2C).

[0006]

Conventionally, in such information distribution, if the information to be distributed is image data that has been discrete wavelet transformed and coded, it is common to recode all of the image data. was. But,
Such image data has a common basic image, and since the modified image data is added to each customer, the entire modified image is re-encoded and transmitted. Was not efficient.

The present invention has been made in view of the above-mentioned conventional example, and when encoding image data in which a certain area of a basic image has been changed, an image can be encoded more efficiently. An object is to provide a processing method and apparatus.

[0008]

In order to achieve the above object, the image processing apparatus of the present invention has the following configuration.
That is, an image processing apparatus that generates and encodes an image in which a predetermined area of the image is changed, the dividing unit dividing the image into a plurality of tiles, and each tile obtained by dividing the image by the dividing unit. Classifying means for classifying the divided tiles into a modified tile including a modified area whose content is modified and a common tile not including the modified area; a first coding means for coding image data of the common tile; Storage means for storing the coded image data coded by the coding means, data adding means for adding other image data to the image data of the changed tile and outputting the changed image data, and output by the data adding means Second encoding means for encoding the changed image data, the encoded image data stored in the storage means, and the image data encoded by the second encoding means And a code generation means for generating coded data of a derived image in which the above-mentioned modified image data is coded by the second coding means according to the type of image data added by the data adding means. It is characterized in that encoded data of the derived image is generated based on the encoded image data and the encoded image data stored in the storage means.

In order to achieve the above object, the image processing apparatus of the present invention has the following configuration. That is, an image processing device for encoding a derived image in which a predetermined area of the basic image is changed, the first conversion means for converting image data of the basic image into conversion coefficients of a plurality of frequency bands, and the first conversion device. First quantizing means for quantizing each of the transform coefficients obtained by the transforming means, and the transform coefficient of each frequency band quantized by the first quantizing means for the first code block having an arbitrary size First entropy coding means for entropy-encoding each of the first code blocks divided by the first code block division means, and first entropy encoding means. A basic image coded data generating means for generating coded data of the basic image from coded generated coded data; A calculating unit that calculates a pixel that generates a second code block relating to a change area having a pixel value different from that of the basic image, and a second converting unit that converts the pixel calculated by the calculating unit into coefficients in a plurality of frequency bands. A second quantizing means for quantizing the coefficient of each frequency band obtained by the second converting means; and a code of an arbitrary size for the coefficient of each frequency band quantized by the second quantizing means. Second code block dividing means for dividing into blocks, and second entropy encoding means for entropy encoding the code blocks divided by the second code block dividing means,
Code block coded data generation means for generating coded data of the second code block from coded data generated by being coded by the second entropy coding means, and generated by the code block coded data generation means The coded data of the second code block is used to replace the corresponding coded code blocks of the coded data of the basic image generated by the basic image coded data generation means, thereby coding the derived image. Derived image coded data generating means for generating encoded data.

In order to achieve the above object, the image processing method of the present invention comprises the following steps. That is, it is an image processing method for generating and encoding an image in which a predetermined area of an image is changed, the dividing step of dividing the image into a plurality of tiles, and each tile obtained by dividing the image by the dividing step. Classifying into a modified tile including a modified area whose content is modified and a common tile not including the modified area; a first coding step of coding image data of the common tile; A storage step of storing coded image data encoded in the encoding step in a memory; a data adding step of adding other image data to the image data of the changed tile and outputting the changed image data; and the data adding step. A second encoding step of encoding the modified image data output by the above, the encoded image data stored in the memory, and the image data encoded in the second encoding step. A code generation step of generating coded data of a derived image in which the modified image data by the second coding step is added according to the type of the image data added by the data adding step. The encoded data of the derived image is generated based on the encoded image data of 1. and the encoded image data stored in the memory.

In order to achieve the above object, the image processing method of the present invention comprises the following steps. That is, it is an image processing method for encoding a derived image in which a predetermined area of a basic image is changed, the first conversion step of converting image data of the basic image into conversion coefficients of a plurality of frequency bands, and the first conversion step. A first quantizing step of quantizing each of the transform coefficients obtained in the transforming step; and a first code block of an arbitrary size for the transform coefficient of each frequency band quantized in the first quantizing step. A first code block dividing step of dividing into
The first code block divided in the first code block dividing step
A first entropy coding step of entropy coding each of the code blocks, and basic image coded data for generating coded data of the basic image from the coded data coded and generated in the first entropy coding step A generation step, a calculation step of calculating a pixel for generating a second code block relating to a modified area having a pixel value different from that of the basic image in the derived image, and the pixel calculated in the calculation step in a plurality of frequency bands. A second transforming step of transforming into a coefficient; a second quantizing step of quantizing the coefficient of each frequency band obtained in the second transforming step;
A second code block dividing step of dividing the coefficient of each frequency band quantized in the quantizing step into code blocks of an arbitrary size, and entropy coding the code block divided in the second code block dividing step. The second entropy coding step and the second data from the coded data generated by being coded in the second entropy coding step.
In the basic image coded data generation step, the code block coded data generation step of generating the coded data of the code block and the coded data of the second code block generated in the code block coded data generation step are performed. Derived image coded data generating step of generating coded data of the derived image by replacing corresponding coded code blocks of the generated coded data of the basic image.

[0012]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

The image processing apparatus according to the present embodiment includes
For example, as shown in FIG. 1, image data of a basic image (basic image 1000) is input. Then, as shown in FIGS. 2A to 2C, different difference data 200 to 202 are added to predetermined areas of the basic image 1000 shown in FIG.
1003 is generated. These plural derived images 1001
Each of 1003 to 1003 is an image to be encoded. still,
The area to which such difference data is added is called a change area.

These plural derived images 1001 to 1003
In the image processing device according to the present embodiment that encodes the basic image 1000, the basic image 1000 is divided into four rectangular regions (tiles) 30 to 33, as shown in FIG. The respective tiles thus obtained are common tiles 30 to 32 common to the respective derived images.
In the example shown in FIGS. 2A to 2C, the difference data 200 to
A change tile 33 including a change area to which 202 is added is sorted. The common tiles 30-32 are then coded only once. Further, the changed tile 33 is encoded as many times as the number of derived image data added to the changed tile 33. In the present embodiment, the derived image data is M
It is assumed that there are types (M = 3 in the example of FIGS. 2A to 2C). In the example of FIG. 3, the changed tile is the lower right tile 33 of 2 × 2 tiles, but the position of the changed tile is not limited to this.

The details of the method will be described below.

The image data to be encoded in the still image in this embodiment is 8-bit monochrome image data. However, for example, a monochrome image represented by a bit number other than 8 bits, such as 4 bits, 10 bits, and 12 bits for each pixel, or a color that represents each color component (RGB / Lab / YCrCb) in each pixel with 8 bits. It is also possible to apply it to the case of multi-valued image data. The present invention can also be applied to the case where the image data is multivalued information indicating the state of each pixel forming the image, for example, a multivalued index value indicating the color of each pixel. When applied to these, each type of multivalued information may be used as monochrome image data described later.

FIG. 4 is a flowchart showing a process until basic image data is input to the image processing apparatus according to the present embodiment, encoded, and encoded data of M types of derivative images is output.

First, in step S1, the variable i is initialized to "1" and the image data of the basic image 1000 (basic image data) is input. Next, in step S2, the basic image data is divided into a plurality of tiles, and each of the plurality of tiles is classified into a common tile (a tile that is not changed) and a changed tile (a tile to which additional data is added). In step S3, processing corresponding to each of the common tile and the changed tile is assigned. In the case of the common tile, the process proceeds to step S4, the image data of the common tile (common tile data) is encoded, and the encoded common tile data is stored in the first buffer 104 (FIG. 5). If the image data of the changed tile (changed tile data), the process proceeds to step S6, and the changed tile data is output to the second buffer 105 (FIG. 5) as it is. In this state, the changed tile data is tile data obtained by dividing the basic image, and does not include the difference data as indicated by 200 to 202 in FIGS. 2A to 2C.

When the storage process of the encoded data of the common tile data and the changed tile data is completed in this way, the process proceeds to step S7, and the difference data added to the i-th derivative image (200 in the example of FIG. 2A). Equivalent) is acquired. This difference data may be stored in advance in a memory or the like, or may be generated appropriately. Next, in step S8, the changed tile data is copied from the second buffer 105 to the added changed tile data generation unit 106 (FIG. 5). Next, in step S9, the i-th difference data is added to the changed tile data to generate the i-th added changed tile data. This is executed by the added changed tile data generation unit 106. Next, in step S10, the i-th added changed tile data is encoded. Then, the procedure proceeds to step S11, and the i-th added modified tile data that has been encoded is combined with the encoded common tile data that has been stored in the first buffer in step S5, and the i-th derivative image code is obtained. Generate and output the digitized data. Next, the process proceeds to step S12, the variable i is compared with the value of M, and it is checked whether or not the generation process of the M types of derived image coded data is completed. Returning to S7, the above-mentioned processing is executed. When all the processes of generating the M types of derived image coded data are completed, this process is completed.

The following is a detailed description of the processing of the image processing apparatus according to the present invention.

FIG. 5 is a block diagram showing the configuration of the image processing apparatus according to the embodiment of the present invention.

In the figure, reference numeral 101 is a basic image data input section for inputting basic image data. A tile dividing unit 102 divides the input basic image data into a plurality of tiles. A tile classification unit 103 classifies each tile into a common tile and a changed tile. 104 is the first buffer,
The common tile data and encoded data obtained by encoding the common tile data are stored. 105 is a second buffer,
Store modified tile data. Reference numeral 106 denotes an added changed tile data generation unit that generates changed tile data by adding the difference data generated by the difference data generation unit to the changed tile data. The difference data generation unit 107 is, for example, as shown in FIG.
Difference data 200 to 202 as shown in (A) to (C)
To generate. A tile data encoding unit 108 inputs and encodes modified tile data to which common tile data and difference data are added. Reference numeral 109 denotes an i-th derivative image data encoding unit, which is the encoded data of the changed tile data encoded by the tile data encoding unit 108 and the encoded data of the basic image data stored in the first buffer 104. And are combined to generate encoded data of the derived image data. 110 is an i-th derivative image encoded image data output unit,
The i-th derivative image data encoding unit 109 encodes the i-th
Output the th derivative image coded image data.

First, in the M kinds of difference data, i = 1
A case will be described where the i = 1st derivative image data is generated and encoded using the th difference data. Then 1 <
The encoding of the i ≦ Mth derivative image data will be described. Note that the difference between i = 1 and other cases is 1
In the case of <i ≦ M, the image of the common tile is encoded and stored, so that the encoding process of the image data of the common tile is unnecessary.

[When i = 1] Basic image data input unit 1
The basic image data input to 01 is the tile dividing unit 10
At 2, it is divided into four tiles, as described above with reference to FIG. Each of the four tiles thus generated is classified into a common tile and a modified tile by the tile classification unit 103. Next, among these classified tiles, common tile data is stored in the first buffer 104, and changed tile data is stored in the second buffer 105. Then, the common tile data stored in the first buffer 104 is coded by the tile data coding unit 108 to become coded common tile data, which is returned to the first buffer 104 and stored again. The processing in the tile data encoding unit 108 will be described later.

The changed tile data stored in the second buffer 105 is added to the changed tile data generator 10
The first difference data copied to No. 6 and generated by the difference data generation unit 107 is added to the changed tile data to generate the first added changed tile data. The first added modified tile data is coded by the tile data coding unit 108 to become the coded first added modified tile data, and the i-th derivative image coded data generation unit 10
9 is output. I-th derivative image coded data generation unit 10
9 synthesizes the coded first added modified tile data and the coded image data of the common tile data stored in the first buffer 104, and further generates a header. Then, as shown in FIG. 6, the encoded data 603 of the first derived image is generated from the header 600, the encoded data 601 of the common tile data, and the encoded first added modified tile data 602. The header 600 contains information such as the size of the basic image input to the basic image data input unit 101, the type indicating whether the basic image is a binary image or a multi-valued image, and the image code to be transmitted. A character string indicating the encryption / transmission device, transmission date and time, and the like are written.

The coded data of the first derived image thus created is the i-th derived image coded data output unit 11
It is output from 0 to the outside.

Next, the tile data encoding unit 108 will be described.

FIG. 7 is a block diagram showing the configuration of tile data encoding section 108 according to the first embodiment.

In the figure, reference numeral 201 denotes a tile data input section for inputting common tile data or first added modified tile data. Reference numeral 202 denotes a discrete wavelet transform unit, which performs a discrete wavelet transform on the tile data input from the tile data input unit 201. Reference numeral 203 denotes a buffer, which stores the transform coefficients subjected to the discrete wavelet transform by the discrete wavelet transform unit 202. Reference numeral 204 is a coefficient quantizer, which inputs and transforms these transform coefficients. Two
An entropy coding unit 05 entropy codes the coefficient values quantized by the coefficient quantization unit 204. 206
Is a tile encoded data output unit.

Common tile data or first added tile data is input to the tile data input unit 201. These tile data are supplied to the discrete wavelet transform unit 202, and the discrete wavelet transform unit 202
Performs a discrete wavelet transform on the input tile data, and decomposes the generated discrete wavelet transform coefficient into a plurality of frequency bands (subbands). In the present embodiment, the discrete wavelet transform for the image data string x (n) is performed based on the following equation.

D (n) = x (2n + 1) -floor {(x (2n) + x (2n + 2)) / 2} r (n) = x (2n) + floor {(d (n-1) + d (n + 1) +2) / 4} where r (n) and d (n) are conversion coefficients and r
(N) is a low frequency subband, and d (n) is a high frequency subband. In the above equation, floor {X} represents the maximum integer value that does not exceed X. This conversion formula is for one-dimensional data. By applying this conversion in the horizontal direction and the vertical direction in order to perform the two-dimensional conversion, LL, HL, LH, as shown in FIG. It can be divided into four HH subbands. Here, L is a low frequency subband and H is a high frequency subband. Then LL
Similarly, the subband is divided into four subbands (see FIG. 8).
(B)), and the LL subband therein is further divided into 4 subbands (FIG. 8C) to make a total of 10 subbands. Each of these 10 subbands will be referred to as HH1, HL1, ..., HH3, as shown in FIG. Here, the number in the name of each subband is the level of each subband. That is, the level 1 subbands are HL1, HH1, LH1 and the level 2 subbands are HL2, HH2, LH2. LL
The subband is a level 0 subband. Also, the decoded data obtained by decoding the subbands up to level n is referred to as the level n decoded data. A decoded image obtained from the decoded data of level n is called a decoded image of level n. Here, the higher the level of the decoded image, the higher the resolution.

It is assumed that the image coded data transmitted to the decoding apparatus according to this embodiment has 10 subbands as described above.

Decoded data obtained by decoding all of these subbands is called complete decoded data. A decoded image obtained by displaying this completely decoded data on an image display device is called a completely decoded image. In the present embodiment, the level 3 decoded image is a complete decoded image.

The 10 sub-bands are temporarily stored in the buffer 20.
3 stored in LL, HL1, LH1, HH1, HL
2, LH2, HH2, HL3, LH3, HH3 in that order,
That is, the sub-bands having a low level are output to the coefficient quantizing unit 204 in order from the sub-band having a high level. The coefficient quantization unit 204 quantizes the wavelet transform coefficient of each subband supplied from the buffer 203 in a quantization step determined for each frequency component, and entropy-encodes the quantized value (coefficient quantized value). Output to the unit 205. Here, when the coefficient value is X and the quantization step value for the frequency component to which this coefficient belongs is q, the quantized coefficient value Q (X) is obtained by the following equation.

Q (X) = floor {(X / q) +0.5} In the above equation, floor {X} represents the maximum integer value that does not exceed X.

FIG. 9 is a diagram for explaining an example of correspondence between each frequency component and the quantization step in this embodiment. As shown in the figure, the high frequency subbands (HL1, LH1, HH1, etc.) are given a larger quantization step than the low frequency subbands (LL, etc.).

The entropy coding unit 205 entropy codes the input coefficient quantized value by arithmetic coding to generate an entropy coded value. The entropy coded value is output to the tile coded data output unit 206. In the tile encoded data output unit 206, FIG.
As shown in 0, the input entropy coded values are arranged in subband units, and a tile header is added to the head of the entropy coded values to generate tile coded data.

FIG. 11 is a diagram for explaining an array of three common tile encoded data.

In this way, the tile encoded data output unit 206
From, the encoded common tile data is sent to the first buffer 104 and stored. In the case of the encoded first added tile data, the i-th derivative image data encoding unit 109
Is output to.

[1 <i ≦ M] When the derived image data is encoded in the case of 1 <i ≦ M, the common tile data has already been encoded and the first buffer 104 has been processed.
Remembered in. Further, the added changed tile data generation unit 106 adds the i-th difference data to the changed tile data to generate the i-th added tile data, and the i-th added tile data is added to the tile data encoding unit 108.
It is encoded by. Then, the i-th derivative image encoded data generation unit 109 inputs the encoded common tile data stored in the first buffer 104 and the encoded first added tile data from the tile data encoding unit 108. Then, the i-th derivative image encoded data is generated and output from the i-th derivative image encoded data output unit 110 to the outside.

As described above, according to the image processing apparatus of the first embodiment, the basic image data is divided into a plurality of tiles, the obtained tiles are divided into common tiles and modified tiles, and the tiles are independently coded. Turn into. At this time, common tile data is encoded only once, and changed tile data is encoded only a number of times according to the type of image data added to the tile data. By doing so, efficient encoding can be achieved without encoding all data of the derived image data including the changed tile data.

[Second Embodiment] In the first embodiment, the basic image data is divided into a plurality of tiles, the obtained tiles are classified into a common tile and a modified tile, and the common tile data is encoded only once. As for the changed tile data, only the type of derived image was encoded.

On the other hand, in the second embodiment, the basic image is encoded without being divided into a plurality of tiles. However, in the second embodiment, as shown in FIG.
In the encoding process, each subband obtained by subjecting the image data to discrete wavelet transform is divided into code blocks, and then entropy encoded. Furthermore, after determining where to add the difference data in the basic image, the pixel (change code block generation pixel) that generates the code block (change code block) related to the change region of each derived image is calculated, and the change is calculated. Encode the generated pixels of the code block. The coded data of the changed code block thus generated and the coded data of the corresponding code block, which is the coded data of the code block spatially corresponding to the code block (corresponding code block), are replaced. Thereby, a plurality of derived images are generated.

The operation of the image processing apparatus according to the second embodiment will be described in detail below.

FIG. 13 is a block diagram showing the structure of the image processing apparatus according to the second embodiment.

In the figure, reference numeral 1801 is a derived image data encoding unit, 1802 is an external output unit, and 1803 is a control unit. Here, the plurality of derivative images are encoded by the derivative image data encoding unit 1801 and then output to the external output unit 1802.
It is temporarily saved in and output to the outside. Control unit 1803
Controls the output of the derived image coded data accumulated in the external output unit 1802 to the outside.

FIG. 14 is a block diagram showing the structure of the derivative image data encoding unit 1801 in the image processing apparatus according to the second embodiment.

In the figure, 1701 is a basic image input unit,
1702 is a buffer, 1703 is a basic image data encoding unit, 1704 is a buffer, 1705 is a difference data position determination unit, 1706 is a change code block generation pixel calculation unit,
1707 is an i-th difference data generation unit, 1708 is an i-th changed code block generation pixel coding unit, 1709 is a code block replacement unit, 1710 is an i-th derivative image coded data output unit, and 1711 is a difference data deletion unit.

FIG. 15 is a flowchart showing the processing in the image processing apparatus according to the second embodiment.

In the figure, first, in step S21, basic image input section 1701 inputs basic image data.
At this time, the variable i is initialized to "1". Step S22
Then, the input basic image data is stored in the buffer 170.
Send to 2 and save temporarily. Next, in step S23,
The basic image data stored in the buffer 1702 is supplied to the basic image data encoding unit 1703. As a result, in step S24, the basic image data encoding unit 1703 encodes the basic image data to generate basic image encoded data. Next, in step S25, the basic image encoded data is output to the buffer 1704 and temporarily stored.

Next, in step S26, the i-th difference data generation unit 1707 generates the i-th difference data (i-th difference data) and sends the area information to the difference data position determination unit 1705. As a result, the difference data position determination unit 1705 determines the position of the difference data in the basic image data from the area information, as shown in FIG. The position information thus determined is sent to the changed code block generation pixel calculation unit 1706, and the changed code block (the code block including the difference data) is calculated as shown in FIG. 22 (step S27). A method of calculating the change code block generation pixel will be described in detail later.

Next, in step S28, step S2
Based on the calculation result of No. 7, the pixel of the basic image data determined to be the generation pixel of the change code block is read from the buffer 1702, and the i-th difference data is read from the i-th difference data generation unit 1707. It is output to the i-change code block generation pixel encoding unit 1708. Next, proceeding to step S29, the i-th change code block generation pixel encoding unit 1708 encodes the generation pixel of the change code block to generate the encoded data of the i-th change code block. After that, the process proceeds to step S30, the coded data of the i-th modified code block and the coded data of the code block corresponding to the i-th code in the basic image coded data are replaced, and the i-th derivative image Generates encoded data and outputs the i-th derivative image encoded data output unit 171.
Enter 0. As a result, the encoded data of the i-th derivative image is output to the external output unit 1802 (FIG. 13) via the i-th derivative image encoded data output unit 1710. Further proceeding to step S31, the difference data deleting unit 1711 deletes the i-th difference data existing in the i-th difference data generating unit 1707. Then, in step S32, the variable i is compared with the value M indicating the number of types of difference data,
It is checked whether or not the processing of the M kinds of difference data is completed. If not completed, the variable i is incremented by 1 and the process returns to step S26.
The above process is repeated for the i-th difference data. In this way, when the processing of the M types of difference data is completed, this processing is completed.

FIG. 16 is a block diagram showing the structure of the basic image data coding unit 1703 according to the second embodiment.

In the figure, 1301 is a basic image data input unit, 202 is a discrete wavelet transform unit, 203 is a buffer, 204 is a coefficient quantization unit, 1305 is a code block division unit, 1306 is an entropy coding unit, and 130 is a unit.
Reference numeral 7 is a basic image coded data output unit. Note that, in FIG. 16, portions common to FIG. 7 according to the above-described first embodiment are denoted by the same symbols, and description thereof will be omitted.

FIG. 23 shows the i-th embodiment according to the second embodiment.
In the block diagram showing the configuration of the modified code block generation pixel encoding unit 1708, the portions common to FIG. 7 according to the first embodiment described above are denoted by the same symbols, and the description thereof will be omitted.

In FIG. 23, 1901 is an i-th change code block generation pixel input unit, 1305 is a code block dividing unit, 1306 is an entropy coding unit, and 1902 is an i-th change code block coded data output unit.

Hereinafter, the basic image data coding unit 1703 (FIG. 16), the modified code block generation pixel calculation unit 1706, the i-th modified code block generation pixel coding unit 1708 (FIG. 23) and the code block replacement unit shown in FIG. 170
The process of the ninth and i-th derivative image encoded data output unit 1710 will be described.

[Basic Image Data Encoding Unit 1703] FIG. 1
6, the basic image data is the basic image data input unit 1
The discrete wavelet transform unit 20 receives the input from 301.
2, the buffer 203, and the coefficient quantization unit 204 sequentially process. Discrete wavelet transform unit 202, buffer 20
3. Since the processing in the coefficient quantization unit 204 is the same as the processing in the above-described first embodiment, the description of those processing units will be omitted.

The coefficient values quantized by the coefficient quantization unit 204 are code block division unit 13 in the form of each subband.
It is input to 05 and is divided into rectangular code blocks as shown in FIG. As the size of this code block, 2n × 2m (where n and m are positive constants, and n = m = 4 in FIG. 12) can be considered.

The code block thus generated is input to the entropy coding unit 1306 and is entropy coded. Then, the encoded value obtained by this entropy encoding is the basic image encoded data output unit 13
07 is output to the buffer 1704 (FIG. 14) and is temporarily stored.

[Changed Code Block Generation Pixel Calculation Unit 17
06] The processing in the changed code block generation pixel calculation unit 170 will be described with reference to FIGS. 17 to 22.
Here, the description is simplified by using a one-dimensional pixel data string.

FIG. 17 shows how the derived image is subjected to discrete wavelet transform to generate the low frequency component L2 and further the low frequency component L1 of the low frequency component L2. Here, as shown in FIG. 18, when the black-painted pixel is the change area, the coefficient of each subband generated from this change area is the coefficient indicated by 1900 to 1904 in FIG. From now on, code block division is further performed as shown in FIG. The resulting modified code block is as shown in FIG. From there,
As shown in FIG. 22, pixels 1900 to 1904
Is determined as the modified code block generation pixel.

[I-th Modification Code Block Generation Pixel Encoding Unit 1708] Referring to FIG. 23, the i-th modification code block generation pixel encoding unit 1708 performs the i-th modification code block generation pixel input unit 1901 with the i-th modification code. In addition, the block generation pixel is input, and further, the encoded data output unit 1902 of the i-th change code block outputs the encoded data of the i-th change code block, and the basic image data encoding unit 1703 ( It is different from the processing of FIG. However, other processing is the same as that of the basic image data encoding unit 1703 (FIG. 16) described above.

[Code Block Replacement Unit 1709] The code block replacement unit 1709 is the code block replacement unit 17
In the working buffer existing in 09, the buffer 1704
Copy the encoded data of the basic image stored in.
Further, the coded data of the corresponding code block in the coded data of the basic image is replaced with the coded data of the i-th modified code block input from the i-th modified code block generation pixel coding unit 1708. Further, the entropy-coded subbands are arranged in units of code blocks as shown in FIG. 24 to generate quasi-i'th derivative image encoded data, and output to the i'th derivative image encoded data output unit 1710.

[I-th Derived Image Encoded Data Output Unit 171
0] The i-th derivative image coded data output unit 1710 is configured as shown in FIG.
As shown in FIG. 5, a header is added to the beginning of the input quasi-i-th derivative image encoded data to generate the i-th derivative image encoded data. The header includes information such as the size of the image input to the basic image input unit 1701 and the type indicating whether the image is a binary image or a multi-valued image.
In addition, a character string indicating the image processing apparatus to be transmitted, transmission date and time, etc. are written. The i-th derivative image coded data generated in this way is output to the external output unit 1802 (FIG. 13).

As described above, the image processing apparatus according to the second embodiment divides the subband of the image data subjected to the discrete wavelet transform into code blocks.
Then, the modified code block of each derived image is encoded.
By doing so, it is possible to efficiently encode the derived image data.

[Third Embodiment] The encoding method according to the second embodiment described above not only enables efficient generation of derived image data, but also in the entropy encoding unit 1306 by processing in code block units. Achieved memory saving. However, memory saving in the entire coding has not been achieved.

On the other hand, in the third embodiment, a method for efficiently generating the derivative image data while saving the memory of the entire encoding will be described.

FIG. 26 is a block diagram showing the structure of the image processing apparatus according to the third embodiment. This is the derivative image data encoding unit 1 in the image processing apparatus of the second embodiment.
801 (FIG. 13) is replaced with a derived image data encoding unit 2201.

FIG. 27 is a block diagram showing the structure of the derived image data coding unit 2201 according to the third embodiment. This is a replacement of the basic image data coding unit 1703 (FIG. 14) in the derived image data coding unit 1801 according to the second embodiment with a basic image data coding unit 2301.

FIG. 28 is a block diagram of the basic image data coding unit 2301 according to the third embodiment. This is because the tile division unit 1501 is provided between the basic image data input unit 1301 and the discrete wavelet transform unit 1302.
, And the basic image encoded data output unit 1 of FIG.
307 is replaced with the basic image encoded data output unit 1502.

The basic image data encoding unit 2301 (see FIG. 2)
When basic image data is input to the basic image data input unit 1301 in 7), the basic image data is divided by the tile dividing unit 1501 into tiles (tiles 0 to 3) as shown in FIG. Then, each tile is independently encoded as in the second embodiment.

The basic image coded data output unit 150
As shown in FIG. 30, No. 2 arranges encoded tile data to generate basic image encoded data, and outputs the basic image encoded data to the buffer 1704. The basic image encoded data is the buffer 17
Since the processing after being output to 04 is the same as that of the above-described second embodiment, the description of the corresponding processing will be omitted.

As described above, according to the image processing apparatus in the third embodiment, the image data is divided into a plurality of tiles, and each tile is coded in the same manner as the coding method in the second embodiment. Turn into. By doing so, it is possible to efficiently generate the derived image data while saving the memory of the entire encoding.

In each of the above-mentioned embodiments, the image data is orthogonally transformed by the discrete wavelet transform, but the present invention is not limited to this. For example, the image data is hierarchized according to the resolution. The encoding method is also included in the scope of the present invention.

Even when the present invention is applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), a device including one device (for example, a copying machine, a facsimile device, etc.) ) May be applied.

Another object of the present invention is to supply a storage medium (or recording medium) recording a program code of software for implementing the functions of the above-described embodiments to a system or apparatus, and to supply a computer (or computer) of the system or apparatus. It is also achieved by the CPU or MPU) reading and executing the program code stored in the storage medium. In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the storage medium storing the program code constitutes the present invention. Further, by executing the program code read by the computer, not only the functions of the above-described embodiment are realized, but also an operating system (OS) running on the computer is executed based on the instruction of the program code. This also includes a case where a part or all of the actual processing is performed and the processing realizes the functions of the above-described embodiments.

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

As described above, according to this embodiment, one image can be efficiently subjected to various change processes and encoded.

[0080]

As described above, according to the present invention, it is possible to more efficiently encode an image when encoding image data in which a certain area of a basic image is changed. There is.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a basic image according to the present embodiment.

FIG. 2 is a diagram showing an example of a derived image according to the present embodiment.

FIG. 3 is a diagram showing an example of tile division of a basic image according to the present embodiment.

FIG. 4 is a flowchart showing a process of generating encoded data of a plurality of types of derivative images in the image processing device according to the first embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of an image processing apparatus according to the first embodiment of the present invention.

FIG. 6 is a diagram illustrating encoded data of a first derivative image.

FIG. 7 is a tile data encoding unit 1 according to the first embodiment.
It is a block diagram which shows the structure of 08.

FIG. 8 is a diagram illustrating a conversion result by discrete wavelet conversion.

FIG. 9 is a diagram illustrating a relationship between a frequency component of a transform coefficient and a quantization step according to the present embodiment.

FIG. 10 is a diagram illustrating tile encoded data according to the present embodiment.

FIG. 11 is a diagram illustrating quasi-image coded data that is composed of coded data obtained by coding common tile data.

FIG. 12 is a diagram illustrating an example of division of code blocks according to the second embodiment of the present invention.

FIG. 13 is a block diagram showing a configuration of an image processing apparatus according to a second embodiment.

FIG. 14 is a block diagram showing a configuration of a derivative image data encoding unit 1801 in the image processing apparatus according to the second embodiment.

FIG. 15 is a flowchart showing a process of generating encoded data of a derivative image in the image processing device according to the second embodiment. Illustration of derived image

FIG. 16 is a block diagram showing a configuration of a basic image data encoding unit 1703 according to the second embodiment.

FIG. 17:

FIG. 18:

FIG. 19:

FIG. 20:

FIG. 21:

FIG. 22 is a diagram illustrating a modified code block generation pixel according to the second embodiment.

FIG. 23 is a block diagram showing a configuration of an i-th changed code block generation pixel encoding unit 1708 according to the second embodiment.

[Fig. 24] Fig. 24 is a diagram for describing quasi-i-th derivative image encoded data according to the second embodiment.

FIG. 25 is a diagram illustrating i-th derivative image encoded data according to the second embodiment.

FIG. 26 is a block diagram showing a configuration of an image processing apparatus according to a third embodiment of the present invention.

FIG. 27 is a block diagram showing the configuration of a derivative image data encoding unit 2201 according to the third embodiment.

FIG. 28 is a diagram showing a block diagram of a basic image data encoding unit 2301 according to the third embodiment.

FIG. 29 is a diagram showing an example of division of a basic image according to the third embodiment.

FIG. 30 is a diagram illustrating basic image encoded data according to the third embodiment.

Continued front page    F-term (reference) 5C059 KK06 KK36 MA24 MC12 MC38                       ME11 PP01 SS06 TA00 TB00                       TC02 TC43 TD05 UA02 UA32                 5C076 AA14 AA36 BA09                 5C078 AA04 BA42 BA53 CA14 CA31                       DA01 DB19                 5J064 AA02 BA09 BA16 BC01 BC16

Claims (18)

[Claims] 1. An image processing apparatus for generating and encoding an image in which a predetermined area of an image has been changed, the dividing means dividing the image into a plurality of tiles, and dividing the image by the dividing means. A classification unit that classifies each tile into a modified tile that includes a modified region whose content is modified and a common tile that does not include a modified region; and a first coding unit that codes the image data of the common tile. Storage means for storing the coded image data coded by the first coding means, data adding means for adding other image data to the image data of the changed tile and outputting the changed image data, and the data addition Second encoding means for encoding the modified image data output from the means, the encoded image data stored in the storage means, and the second encoding means A code generation unit that generates coded data of a derived image that is a combination of image data, and the changed image by the second coding unit according to the type of image data added by the data addition unit. An image processing apparatus, wherein coded data of the derived image is generated based on coded image data of data and the coded image data stored in the storage means. 2. Each of the first and second encoding means includes a conversion means for converting the image data into coefficients of a plurality of frequency bands, and a conversion coefficient corresponding to the frequency band obtained by the conversion means. The image processing apparatus according to claim 1, further comprising: a quantizing unit that quantizes the image, and an entropy encoding unit that entropy-encodes the quantized coefficient quantized by the quantizing unit. 3. The transforming means obtains the coefficient by performing a discrete wavelet transform.
The image processing device according to item 1. 4. The image processing apparatus according to claim 3, wherein the conversion means recursively converts the low frequency band. 5. An image processing apparatus for encoding a derived image in which a predetermined area of a basic image has been changed, the first conversion means converting image data of the basic image into conversion coefficients of a plurality of frequency bands, First quantizing means for quantizing each of the transform coefficients obtained by the first transforming means; and the transform coefficient of each frequency band quantized by the first quantizing means having an arbitrary size First code block dividing means for dividing into one code block, first entropy encoding means for entropy encoding each of the first code blocks divided by the first code block dividing means, and the first entropy code Basic image coded data generation means for generating coded data of the basic image from coded data coded and generated by the coding means; Calculation means for calculating a pixel for generating a second code block relating to a change area having a pixel value different from that of the basic image in the image; and second for converting the pixel calculated by the calculation means into a plurality of frequency band coefficients. Transforming means; second quantizing means for quantizing the coefficient of each frequency band obtained by the second transforming means; and coefficient of each frequency band quantized by the second quantizing means to an arbitrary size Second code block dividing means for dividing into code blocks, second entropy encoding means for entropy encoding the code blocks divided by the second code block dividing means, and encoding by the second entropy encoding means A code block coded data generator for generating coded data of the second code block from the coded data generated And corresponding coded data of the basic image coded data generated by the basic image coded data generation means by the coded data of the second code block generated by the code block coded data generation means. Derived image coded data generating means for generating coded data of the derived image by replacing the code blocks
An image processing apparatus comprising: 6. The image processing apparatus according to claim 5, wherein the first and second transforming means include a discrete wavelet transform. 7. The image processing apparatus according to claim 6, wherein the first and second conversion means recursively divides a low frequency band. 8. The apparatus further comprises a dividing unit that divides the image data of the basic image into a plurality of tiles, and the first converting unit converts the image data of each tile divided by the dividing step. The image processing apparatus according to claim 5. 9. An image processing method for generating and encoding an image in which a predetermined area of an image is changed, the method comprising: a dividing step of dividing the image into a plurality of tiles; and a dividing step obtained by the dividing step. A classification step of classifying each tile into a modified tile including a modified area whose content is modified and a common tile not including the modified area; a first coding step of coding image data of the common tile; A storage step of storing coded image data encoded by the first encoding step in a memory; a data addition step of adding other image data to the image data of the changed tile and outputting the image data as changed image data; A second encoding step of encoding the modified image data output in the data adding step, the encoded image data stored in the memory, and the encoding in the second encoding step A code generation step of generating coded data of a derived image that is a combination of the generated image data, and the second coding step according to the type of the image data added in the data adding step. An image processing method, wherein encoded data of the derived image is generated based on the encoded image data of the modified image data and the encoded image data stored in the memory. 10. Each of the first and second encoding steps includes a conversion step of converting image data into a coefficient of a plurality of frequency bands, and a conversion coefficient corresponding to the frequency band obtained by the conversion step. 10. The image processing method according to claim 9, further comprising: a quantization step of quantizing the image data, and an entropy coding step of entropy coding the quantized coefficient quantized by the quantization step. 11. The image processing method according to claim 10, wherein in the transforming step, the coefficient is obtained by performing a discrete wavelet transform. 12. The image processing method according to claim 11, wherein in the converting step, a low frequency band is converted recursively. 13. An image processing method for encoding a derived image in which a predetermined area of a basic image is changed, the first conversion step of converting image data of the basic image into conversion coefficients of a plurality of frequency bands, A first quantizing step of quantizing each of the transform coefficients obtained in the first transforming step; and transforming the transform coefficient of each frequency band quantized in the first quantizing step into an arbitrary size A first code block dividing step of dividing into one code block, and the first code block dividing in the first code block dividing step
A first entropy coding step of entropy coding each of the code blocks, and basic image coded data for generating coded data of the basic image from the coded data coded and generated in the first entropy coding step A generation step, a calculation step of calculating a pixel that generates a second code block relating to a changed area having a pixel value different from that of the basic image in the derived image, and the pixel calculated in the calculation step in a plurality of frequency bands. A second transforming step of transforming into a coefficient, a second quantizing step of quantizing the coefficient of each frequency band obtained in the second transforming step, and a second quantizing step of each frequency band quantized in the second quantizing step. A second code block dividing step of dividing the coefficient into code blocks of arbitrary size; and a code block divided in the second code block dividing step. Second entropy coding step for entropy coding a clock, and code block coding for generating coded data of the second code block from coded data generated by being coded in the second entropy coding step. The encoded data of the second code block generated in the code block encoded data generating step corresponds to the encoded data of the basic image generated in the basic image encoded data generating step. A derivative image coded data generating step of generating coded data of the derivative image by replacing coded code blocks. 14. The image processing method according to claim 13, wherein the transform coefficients are obtained by discrete wavelet transform in the first and second transform steps. 15. The image processing method according to claim 14, wherein the low frequency band is recursively divided in the first and second conversion steps. 16. The method further comprises a dividing step of dividing the image data of the basic image into a plurality of tiles, and the first converting step converts the image data of each tile divided in the dividing step. The image processing method according to claim 13. 17. A storage medium storing a program for executing the image processing method according to claim 9. Description: 18. A program for executing the image processing method according to claim 9. Description: