JPH10304352A - Coded noise elimination device and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate block distortion of a reproduced image without losing a substantial image component possessed in a reproduced image in the coding decoding system by using a discrete cosine transformation(DCT) processing. SOLUTION: A device divides an image into a plurality of coding blocks to eliminate coded noise in a reproduced image through coding/decoding by applying conversion coding/decoding to the coded blocks. In this case, a DCT section 4a divides a reproduced image into a plurality of post-processing blocks having a block border different from the coded block, and conversion coding is conducted in the post processing block; a decision section 6 for coefficient amplitude suppression characteristics determines the amplitude suppression characteristics of the transformation coefficients in the post processing block; based on the result of the decision section 6, a coefficient amplitude suppression section 5 executes amplitude suppression to the transformation coefficients, that is, output of the DCT section 4a, and an IDCT section 7a applies conversion decoding to the transformation coefficients produced by amplitude suppression. Then the frequency component possessed by the image is estimated from the transformation coefficients in a video stream and the band is limited by using the DCT again.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to coding noise elimination, and more particularly to block DCT (Discrete Cosine Transform).
The present invention relates to a coding noise elimination device and a coding noise elimination method for removing coding noise of a reproduced image coded and decoded by a coding and decoding method using block transform coding such as rm).

[0002]

2. Description of the Related Art FIG. 11 is a block diagram showing a configuration of a conventional coding noise removing apparatus. In the figure, 1a is an input terminal, 3 is a stream combining unit, 8 is a low-pass filter,
2a is an output terminal.

[0003] The video stream 1101 input from the input terminal 1a is decoded by the stream decoding unit 3. The decoded image signal 1102 is band-limited by the low-pass filter 8 and output from the output terminal 2a.

FIG. 12 is a diagram showing a schematic configuration of an encoding portion in an encoding / decoding device using DCT. In the figure, 1b is an input terminal, 4b is a DCT unit, 9 is a quantization unit, and 2b is an output terminal. The image 1201 input from the input terminal 1b is output from the output terminal 2b as a quantized transform coefficient 1203 after passing through the DCT unit 4b and the quantization unit 9.

FIG. 13 is a diagram showing a schematic configuration of a decoding part in an encoding / decoding device using DCT. In the figure, 1c is an input terminal, 10 is an inverse quantization unit, and 7b is an ID.
The CT unit and 2c are output terminals. The quantized transform coefficient 1301 input from the input terminal 1c is
0 and the reproduced image 1303 after passing through the IDCT unit 7b.
Is output from the output terminal 2c. FIG. 14 is a diagram showing an encoding block.

Next, the operation will be described. Currently, MPE
G2 (ISO / IEC 13818-2) and other general-purpose video encoding / decoding methods are based on block DCT (Discrete Cosine T
ransform). FIGS. 12 and 13 show schematic configurations of an encoding portion and a composite portion in this system, respectively. In this method, encoding and decoding are performed in the following procedure.

[0007] In encoding, first, the screen is divided into block units (hereinafter, referred to as encoded blocks) composed of N (pixels) x N (lines) as shown in FIG. Next, FIG.
As shown in (2), the DCT unit 4b assigns 2
Perform a dimensional DCT. At this time, data compression can be performed by expressing the transform coefficients after the two-dimensional DCT with a small number of bits. Hereinafter, in the present application, the expression with this small number of bits is referred to as quantization (see the quantization unit 9 in FIG. 12).

In an actual system, the actually quantized transform coefficients are further subjected to another encoding method such as entropy encoding. However, they are not involved in the present application and will not be described here.

In the decoding, as shown in FIG. 13, the inversely quantized transform coefficients are inversely quantized by the inverse quantizer 10, and then the two-dimensional inverse DCT (IDCT) is performed by the IDCT unit 7b.
To obtain a decoded image.

In the video encoding / decoding method, when decoding is performed at a high compression rate, that is, when the transform coefficient is expressed with a very small number of bits, noise in a decoded image increases. At this time, noise recognized in a block shape is called block distortion. Block distortion occurs when DCT is performed and quantized for each block. This block distortion greatly impairs the image quality of the decoded image.

FIG. 11 shows a conventional coding noise eliminator for removing the above block distortion. In the figure, an encoded stream input from an input terminal 1b is decoded by a stream decoding unit 3. This decoded image is band-limited in the low-pass filter 8. By limiting the band, block distortion can be removed. This is because block distortion is caused by discontinuity of pixel values at block boundaries, that is, high frequency components.

[0012]

As described above, in the conventional coding noise elimination apparatus, low-pass filtering is simply performed, and the band limitation is performed without particularly considering the frequency band of the original image signal. Had been given. Therefore, the frequency component originally owned by the encoded stream is damaged,
There has often been the problem of losing image definition.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a coding noise elimination apparatus and a coding noise elimination method for removing block distortion in consideration of a frequency band of an original image signal. The purpose is to:

[0014]

SUMMARY OF THE INVENTION In view of the above objects, a first aspect of the present invention is to divide an image into a plurality of coding blocks and perform transform coding and decoding in the coding blocks. What is claimed is: 1. An encoding noise elimination device for removing encoding noise of an encoded and decoded reproduced image, comprising: dividing the reproduced image into a plurality of post-processing blocks having block boundaries different from the encoded blocks; Transform coding means for performing transform coding in the processing block, coefficient amplitude suppression characteristic determining means for determining the amplitude suppression characteristic of the transform coefficient in the post-processing block, and the conversion based on the determination result of the coefficient amplitude suppression characteristic determining means. A coefficient amplitude suppressing means for suppressing the amplitude of the transform coefficient output from the encoding means; and a transform decoding means for transforming and decoding the transformed coefficient whose amplitude has been suppressed. The coding noise removal device according to claim certain.

According to a second aspect of the present invention, the amplitude suppression characteristic of the transform coefficient in the coefficient amplitude suppression characteristic determining means is determined based on a horizontal maximum order and a vertical maximum order in the coding block. An encoding noise removing apparatus according to claim 1.

According to a third aspect of the present invention, in the coefficient amplitude suppression characteristic determining means, the maximum horizontal order and the maximum vertical order for each coding block are averaged for all coding blocks in the entire screen. 3. The apparatus according to claim 2, wherein the coding noise is eliminated.

According to a fourth aspect of the present invention, in the coefficient / amplitude suppression characteristic determining means, the horizontal maximum order and the vertical maximum order for each coding block are respectively equal to a predetermined number of coding blocks included in the post-processing block. 3. The coding noise eliminator according to claim 2, wherein the horizontal maximum order or the vertical maximum order is averaged.

According to a fifth aspect of the present invention, the post-processing block around the image is a block of the same size as the post-processing block in the screen by using a pixel value in the screen. Item 5 is the coding noise elimination device according to any one of Items 1 to 4.

According to a sixth aspect of the present invention, the post-processing block around the image is a block having a size different from that of the post-processing block in the screen. In the coding noise removing apparatus described above.

According to a seventh aspect of the present invention, an image is divided into a plurality of encoded blocks, and transform encoding is performed on the encoded blocks to encode a reproduced image encoded and encoded. What is claimed is: 1. A coding noise removing method for removing noise, comprising: a transform coding step of dividing the reproduced image into a plurality of post-processing blocks having block boundaries different from the coding blocks and performing transform coding in the post-processing blocks. A coefficient amplitude suppression characteristic determining step of determining an amplitude suppression characteristic of a transform coefficient in the post-processing block; and an amplitude suppression of a transform coefficient which is a result of the transform coding step based on a determination result of the coefficient amplitude suppression characteristic determining step. And a conversion decoding step of converting and decoding the amplitude-suppressed transform coefficients. That.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below according to each embodiment.

Embodiment 1 FIG. 1 is a block diagram showing a configuration of a coding noise elimination device according to an embodiment of the present invention. In the figure, 1a is an input terminal, 6 is a coefficient amplitude suppression characteristic determining unit, 3 is a stream combining unit, and 4a is a DCT.
Section, 5 is a coefficient amplitude suppression section, 7a is an IDCT section, and 2
a is an output terminal.

The video stream 101 input from the input terminal 1a is decoded by the stream decoding unit 3. The first output 102 of the stream decoding unit 3 is DC
The second output 104 is provided to the T unit 4a and to the coefficient amplitude suppression characteristic determining unit 6, respectively. Output 103 of DCT section 4a
Is given to the first input of the coefficient amplitude suppression unit 5, while
The output 105 of the coefficient amplitude suppression characteristic determination unit 6 is provided to a second input of the coefficient amplitude suppression unit 5. The output 106 of the coefficient amplitude suppression unit 5 is provided to the IDCT unit 7a. And I
The output 107 of the DCT unit 7a is output from the output terminal 2a.

FIG. 2 is a diagram showing an example of the coefficient amplitude suppression characteristic determining section 6 of FIG. In the figure, reference numeral 11 denotes a horizontal maximum order detection unit, 12 denotes a vertical maximum order detection unit, 13a and 13b denote full screen averaging units, and 14 denotes a suppression characteristic instructing unit.

DC output from the stream decoding unit 3
Information 104 on the distribution state of the T coefficient is given to the horizontal maximum order detection unit 11 and the vertical maximum order detection unit 12. The output 401 of the horizontal maximum order detector 11 is provided to a first input of the suppression characteristic instructor 14 via the full screen averaging unit 13a. Also, the output 4 of the vertical maximum order detection unit 12
03 is given to the second input of the suppression characteristic instructing unit 14 via the full screen averaging unit 13b. The output of the suppression characteristic instructing unit 14 is provided to the coefficient amplitude suppression unit 5 as an output 105 of the coefficient amplitude suppression characteristic determination unit 6.

It should be noted that the coefficient amplitude suppression characteristic deciding section 6 is a coefficient amplitude suppression characteristic deciding section, the DCT section 4a is a transform coding section,
The coefficient amplitude suppressing unit 5 is a coefficient amplitude suppressing unit, and the IDCT unit 7a
Constitutes the conversion compounding means.

Next, the operation will be described. As described above, in a video encoding / decoding system using DCT,
When encoding is performed at a high compression rate, block distortion often occurs. The block distortion is generated by performing DCT for each block and roughly quantizing, and is recognized as a reproduced image as if each block was divided by a boundary line.

In the conventional apparatus, the removal of block distortion is realized by using a low-pass filter. In the present invention, however, the block distortion is removed by performing DCT again without using the low-pass filter. Reduce.

In FIG. 1, a video stream 101 input from an input terminal 1a is decoded by a stream decoding unit 3. At this time, the video stream 10
1 is assumed to have been encoded by the video encoding / decoding system using DCT as described above.

The stream decoding unit 3 decodes the video stream 101 and sends out the decoded image data 102 to the DCT unit 4a, and supplies information 104 on the distribution state of the DCT coefficients to the coefficient amplitude suppression characteristic determining unit 6. I do. The transmission of the information on the distribution state of the DCT coefficient will be described later.

The DCT unit 4a performs DCT for the purpose of reducing block distortion. At this time, a block that performs DCT in the DCT unit 4a (hereinafter, referred to as a post-processing block)
Is obtained by shifting the position by N / 2 in the horizontal direction and the vertical direction on the screen with respect to the coding block of FIG. 14 as shown in FIG.

At this time, the coding block is usually
Since the post-processing blocks are arranged so as to cover the entire screen as shown in (1), the boundary between the screen and the post-processing block does not match around the screen. Therefore, a different process is performed between a post-processing block completely included in the screen and a post-processing block around the screen including the screen boundary. Hereinafter, first, the processing in the former will be generally described, and then, the processing in the latter will be described.

The transform coefficient 103, which is the output of the DCT unit 4a
In the coefficient amplitude suppression unit 5, the amplitude of the high frequency coefficient is suppressed for the purpose of reducing block distortion. FIG. 4 shows an example of this suppression characteristic. The magnification for suppression is shown in each square.

At this time, the suppression characteristic should not be uniquely determined, but needs to be determined based on the frequency characteristics of the original image and the local frequency characteristics of the original image. The determination of the suppression characteristic is performed by the coefficient amplitude suppression characteristic determination unit 6. Hereinafter, an example of the coefficient amplitude suppression characteristic determination unit 6 will be described.

In the example of the coefficient amplitude suppression characteristic determining section 6 shown in FIG. 2, a uniform amplitude suppression characteristic is given to all the post-processing blocks in the screen. Hereinafter, the procedure will be described.

In FIG. 2, the horizontal maximum order detector 11 calculates the maximum order in the horizontal direction of non-zero (not "0") transform coefficients in each coding block. FIG. 5 shows the concept of the maximum horizontal order. In this case, the maximum horizontal order is 5. Similarly, the vertical maximum order detecting unit 12 obtains the maximum order in the vertical direction of the non-zero transform coefficient in each coding block. FIG. 6 shows the concept of the maximum vertical order. In this case, the maximum vertical order is 4.

The horizontal maximum order 401 for each coding block obtained by the horizontal maximum order detection unit 11 is averaged by the full-screen averaging unit 13a. At this time, the averaging is performed on all the coded blocks in the entire screen. Thereby, the distribution of the horizontal frequency component of the entire encoded image is estimated.

Similarly, the vertical maximum order 403 for each encoded block obtained by the vertical maximum order detection unit 12 is averaged by the full screen averaging unit 13b. Also at this time, the averaging is performed on all the encoded blocks in the entire screen. As a result, the distribution of the vertical frequency components of the entire encoded image is estimated.

The horizontal maximum order 402 and the vertical maximum order 404 thus averaged over the entire screen are sent to the suppression characteristic instructing unit 14, respectively, and are offset to the horizontal maximum order and the vertical maximum order as follows. The values are added, and the horizontal suppression information and the vertical suppression information are output to the coefficient amplitude suppression unit 5. (Horizontal suppression information) = (horizontal maximum order averaged over all screens)
+ (Constant) (vertical suppression information) = (vertical maximum order averaged over the entire screen)
+ (Constant)

In this way, the coefficient amplitude suppression characteristic determining section 6
Based on the horizontal suppression information and the vertical suppression information 105 output from the

[0041]

(Equation 1)

Based on the above equation (1), the amplitude of the transform coefficient is suppressed as shown in FIG. At this time, U and V are constants,

[0043]

(Equation 2)

Corresponds to the horizontal suppression information,

[0045]

(Equation 3)

Corresponds to the above vertical suppression information. In addition, FIG.

[0047]

(Equation 4)

The case of FIG.

In this case, the horizontal transform coefficient order μ and the vertical transform coefficient order ν in FIG. 4 are applied to the case classification under the equation (1) to obtain ω (μ) and ψ (ν).
This is obtained by calculating k (μ, ν) in the equation (1). For example, from the condition of the above equation (2), cosω (μ) is 1 until μ = 3,
cosψ (ν) is 1 until ν = 2.

The DCT coefficient suppressed in this way is represented by IDC
The inverse DCT (IDCT) is performed in the T unit 7a and output from the output terminal 2a as an output 107. By the above procedure,
Removal of block distortion in a reproduced image is realized.

As described above, on the screen,
Since the positions of the coded block and the post-processing block are shifted, different processing is required between the post-processing block completely included in the screen and the post-processing block around the screen including the screen boundary. Become.

Regarding the latter, that is, the processing in the post-processing block including the boundary of the screen, the post-processing block having a predetermined size cannot be formed in the peripheral portion of the screen. Therefore, for example, as shown in FIG. 7, for example, as shown in FIG. 7, the pixel value at the nearest screen boundary is used as the pixel value outside the screen.

Embodiment 2 FIG. 8 is a diagram showing another example of the coefficient amplitude suppression characteristic determining unit 6 of FIG. In the example of FIG. 2, a uniform amplitude suppression characteristic is given to all post-processing blocks in the screen, whereas in this configuration, a uniform amplitude suppression characteristic is given to each post-processing block. . In the figure, reference numeral 11 denotes a horizontal maximum order detection unit, 12 denotes a vertical maximum order detection unit, 15a and 15b denote local screen averaging units, and 14 denotes a suppression characteristic instructing unit.

The procedure will be described below. In FIG. 8, the horizontal maximum order detector 11 and the vertical maximum order detector 12 find the maximum order in the horizontal and vertical directions of the non-zero transform coefficient in each coding block, as in FIG. .

The horizontal maximum order 501 and the vertical maximum order 503 obtained by the horizontal maximum order detection unit 11 and the vertical maximum order detection unit 12 are locally averaged by the local screen averaging units 15a and 15b, respectively.

That is, since each of the post-processing blocks other than the peripheral portion of the screen is shifted in the horizontal and vertical directions by N / 2 as shown in FIG. 3, it includes the pixels of the four coding blocks. The average of the horizontal maximum order and the average of the vertical maximum order in the block are applied to the post-processing block. However, the averaging need not necessarily be four averaging, but may be any local averaging of the coded blocks existing around the post-processing block.

The locally averaged horizontal maximum order 502 and vertical maximum order 504 obtained in this way are sent to the suppression characteristic instructing unit 14 and offset to the horizontal maximum order and the vertical maximum order as follows. The values are added, and the horizontal suppression information and the vertical suppression information 105 are output to the coefficient amplitude suppression unit 5. (Horizontal suppression information) = (local averaged horizontal maximum order)
+ (Constant) (vertical suppression information) = (local averaged vertical maximum order)
+ (Constant)

Embodiment 3 FIG. Further, in the above-described embodiment, with respect to the processing in the post-processing block including the screen boundary including the screen boundary, the pixel value of the nearest screen boundary is used as the pixel value outside the screen in FIG. As shown in (1), a pixel value inside the screen may be used as a pixel value outside the screen using a screen boundary as a target axis.

Embodiment 4 FIG. Further, regarding the processing in the post-processing block in the peripheral portion of the screen, as shown in FIG.
The post-processing block is divided into N / 2 × N and N according to the position.
A block may be configured with a size of × N / 2 or N / 2 × N / 2.

In each of the above embodiments, the luminance signal,
Although the format of an image signal such as a color difference signal or an RGB signal has not been particularly described, each of the above embodiments is applicable to any case without depending on the format of the image signal.

The above embodiments can be applied without distinction between still images and moving images.

Further, each of the above embodiments can be realized by either hardware or software.

Further, in each of the above embodiments, application to a video stream encoded by a video encoding method using DCT has been described, but the present invention is not limited to this.
The present invention can be applied to any video encoding / decoding system using any block transform encoding.

[0064]

As described above, according to the first aspect of the present invention, an image is divided into a plurality of coding blocks, and the coding and decoding is performed by performing the transform coding and decoding in the coding blocks. A coding noise elimination apparatus for removing coding noise of a reproduced image, comprising: dividing the reproduced image into a plurality of post-processing blocks having block boundaries different from the coding block; And a coefficient amplitude suppression characteristic determining means for determining an amplitude suppression characteristic of a transform coefficient in the post-processing block, and an output of the conversion encoding means based on a determination result of the coefficient amplitude suppression characteristic determining means. A block conversion code is provided, which includes a coefficient amplitude suppression unit that performs amplitude suppression of a certain conversion coefficient and a conversion decoding unit that performs conversion decoding of the conversion coefficient whose amplitude has been suppressed. Effects such that can provide an encoding noise removal device is obtained to remove the block distortion by considering the frequency band of the original image signal by using the reduction.

According to a second aspect of the present invention, the amplitude suppression characteristic of the transform coefficient in the coefficient amplitude suppression characteristic determining means is
Since the determination is made on the basis of the horizontal maximum order and the vertical maximum order in the coding block, it is possible to provide a coding noise removal device that easily and accurately removes block distortion in consideration of the frequency band of the original image signal. And the like.

In the third aspect of the present invention, in the coefficient amplitude suppression characteristic determining means, the horizontal maximum order and the vertical maximum order for each coding block are averaged with respect to all coding blocks in the entire screen. Therefore, it is possible to obtain an effect such as providing a coding noise elimination device that enables more appropriate removal of block distortion.

According to a fourth aspect of the present invention, in the coefficient amplitude suppression characteristic determining means, the horizontal maximum order and the vertical maximum order for each of the coding blocks are respectively equal to a predetermined number of coding blocks included in the post-processing block. Are obtained by averaging the horizontal maximum order or the vertical maximum order in, and it is possible to obtain an effect such as providing a coding noise elimination device capable of more appropriately removing block distortion.

According to the fifth aspect of the present invention, the post-processing blocks around the image are converted into blocks of the same size as the post-processing blocks in the screen by using the pixel values in the screen. It is possible to provide an encoding noise elimination device that eliminates block distortion by taking into account the frequency band of an original image signal.

According to the sixth aspect of the present invention, the post-processing block around the image is a block having a different size from the post-processing block inside the screen. Advantages such as providing a coding noise elimination device that eliminates block distortion in consideration of a band can be obtained.

According to a seventh aspect of the present invention, an image is divided into a plurality of coded blocks, and transform coding is performed on the coded blocks, thereby coding the coded and decoded reproduced image. In a coding noise removal method for removing noise, a transform coding step of dividing the reproduced image into a plurality of post-processing blocks having block boundaries different from the coding block and performing transform coding in the post-processing block, A coefficient amplitude suppression characteristic determining step of determining an amplitude suppression characteristic of a transform coefficient in the post-processing block, and performing an amplitude suppression of a transform coefficient which is a result of the transform coding step based on a determination result of the coefficient amplitude suppression characteristic determining step. A coefficient amplitude suppression step and a conversion decoding step for converting and decoding the amplitude-reduced transform coefficients are provided. Considering the frequency band of the image signal effects such that can provide an encoding noise removing method for removing block distortion is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a coding noise removing apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an embodiment of a coefficient amplitude suppression characteristic determining unit in FIG. 1;

FIG. 3 is a diagram showing a post-processing block according to the present invention.

FIG. 4 is a diagram illustrating an example of a coefficient amplitude suppression characteristic according to the present invention.

FIG. 5 is a diagram showing the concept of the maximum horizontal order in the present invention.

FIG. 6 is a diagram showing the concept of the vertical maximum order in the present invention.

FIG. 7 is a diagram illustrating an example of a configuration of a post-processing block in a peripheral portion of a screen according to the present invention.

FIG. 8 is a diagram showing another embodiment of the coefficient amplitude suppression characteristic determining unit of FIG. 1;

FIG. 9 is a diagram showing another example of a configuration of a post-processing block in a peripheral portion of a screen according to the present invention.

FIG. 10 is a diagram showing still another example of a configuration of a post-processing block in a peripheral portion of a screen according to the present invention.

FIG. 11 is a diagram showing a configuration of a conventional coding noise elimination device.

FIG. 12 is a diagram illustrating a schematic configuration of an encoding unit in an encoding / decoding device using DCT.

FIG. 13 is a diagram illustrating a schematic configuration of a decoding unit in an encoding / decoding device using DCT.

FIG. 14 is a diagram showing an encoding block.

[Explanation of symbols]

1a input terminal, 2a output terminal, 3 stream decoding unit, 4a DCT unit, 5 coefficient amplitude suppression unit, 6 coefficient amplitude suppression characteristic determination unit, 7 IDCT unit, 11 horizontal maximum order detection unit, 12 vertical maximum order detection unit, 13a, 13b
Full screen averaging unit, 14 suppression characteristic instructing unit, 15a, 1
5b Local screen averaging unit.

Claims (7)

[Claims] 1. Dividing an image into a plurality of coding blocks,
A coding noise elimination device that removes coding noise of a coded and decoded playback image by performing transform coding and decoding in the coding block, wherein the playback image is defined as the coding block. Transform coding means for dividing into a plurality of post-processing blocks having different block boundaries and performing transform coding in the post-processing block; and coefficient amplitude suppression characteristic determining means for determining an amplitude suppression characteristic of a transform coefficient in the post-processing block. A coefficient amplitude suppressor for suppressing the amplitude of the transform coefficient output from the transform encoder based on the determination result of the coefficient amplitude suppression characteristic determiner, and a transform decoder for transforming and decoding the transformed coefficient whose amplitude is suppressed. A coding noise elimination device comprising: coding means. 2. The code according to claim 1, wherein the amplitude suppression characteristic of the transform coefficient in said coefficient amplitude suppression characteristic determination means is determined based on a maximum horizontal order and a maximum vertical order in said coding block. Noise reduction device. 3. The coefficient amplitude suppression characteristic determining means, wherein the maximum horizontal order and the maximum vertical order for each coding block are averaged for all coding blocks in the entire screen. The coding noise removing device according to claim 2. 4. The coefficient amplitude suppression characteristic determining means, wherein the horizontal maximum order and the vertical maximum order of each coding block are respectively the horizontal maximum order and the vertical maximum order in a predetermined number of coding blocks included in the post-processing block. 3. The apparatus according to claim 2, wherein the orders are averaged. 5. The post-processing block around the image is a block of the same size as the post-processing block in the screen by using pixel values in the screen. 3. The coding noise elimination device according to item 1. 6. The apparatus according to claim 1, wherein the post-processing block around the image is a block having a size different from that of the post-processing block inside the screen. . 7. Dividing an image into a plurality of coding blocks,
A coding noise elimination method for removing coding noise of a coded and decoded playback image by performing transform coding and decoding in the coding block, wherein the playback image is defined as the coding block. A transform coding step of dividing into a plurality of post-processing blocks having different block boundaries and performing transform coding in the post-processing block; and a coefficient amplitude suppression property determining step of determining an amplitude suppression property of a transform coefficient in the post-processing block. A coefficient amplitude suppressing step of performing amplitude suppression of a transform coefficient as a result of the transform coding step based on a result of the determination of the coefficient amplitude suppressing characteristic determining step, and a transform decoding step of transforming and decoding the amplitude suppressed transform coefficient. A coding method, comprising: a coding step.