JP2001352550A - Image decoding apparatus and image decoding method - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To enable more efficient decoding of a binary image than before. An apparatus for decoding encoded data obtained by encoding a binary image for each block to obtain a binary image of a target block, comprising: a target frame having the target block to be decoded; A reference binary image generating means for obtaining a reference binary image from a previously decoded frame; a blocking means 2 (802) for obtaining a reference block including a plurality of pixels from the reference binary image; Statistical model selecting means (803) for selecting a statistical model from a plurality of statistical models based on a state of a reference pixel corresponding to a target pixel in the target block and a state of surrounding pixels of the reference pixel, An image decoding apparatus comprising: an entropy decoding unit (801) for decoding the encoded data based on the selected statistical model to obtain a binary image of the target block.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image decoding apparatus and an image decoding method which can be used for transmitting and storing an image, especially a binary moving image.

[0002]

2. Description of the Related Art Conventionally, when synthesizing an image, information indicating an occupied area of an object and transparency, called an alpha value, may be added in addition to the luminance of the object. This alpha value is determined for each pixel, 1 means opaque or occupied, and 0 means completely transparent or occupied. That is, when fitting an image of an object to a background image, an alpha value is required. Hereinafter, an image having only this alpha value is called an alpha plane.

[0003] In the case of clouds, frosted glass, etc., the alpha value may be represented by an intermediate value of [0, 1].
In some cases, the two values {0, 1} are sufficient.

[0004] For encoding a general binary alpha plane, CCITT used in a conventional facsimile or the like is used.
International Standard for Binary Image Coding Technology MR, MMR
Coding or coding standardized by JBIG can be used. These are collectively called still binary image coding.
In still binary image coding, low-order pixels are predicted from high-order pixels in the scanning direction, and the difference can be efficiently coded by entropy coding.

[0005]

In a binary moving image such as two continuous alpha planes of a moving image, correlation can be used between consecutive frames. That is,
Compared to predicting a lower pixel from an upper pixel in the scanning direction and encoding the difference, the correlation obtained in advance is higher
Efficient encoding can be achieved by predicting the pixel to be encoded from the value image and encoding the difference.

However, in the conventional still binary image coding,
Even when the encoding device and the decoding device each obtain a binary image having a very high correlation with the binary image to be encoded and decoded, only the upper and lower correlations in the scanning direction are obtained. And a problem that a large amount of code is required.

The present invention has been made in consideration of such a conventional problem, and provides an image decoding apparatus and an image decoding method capable of performing decoding more efficiently than using a conventional binary image decoding technique. The purpose is to provide.

[0008]

According to the first aspect of the present invention, there is provided an image decoding apparatus for decoding encoded data obtained by encoding a binary image for each block and obtaining a binary image of a target block. A reference binary image generating means for obtaining a reference binary image from a frame decoded before a target frame having the target block to be decoded; and a reference block including a plurality of pixels from the reference binary image. A reference block generating means for obtaining, and a state of a reference pixel corresponding to a target pixel in the target block in the reference block, and a state of surrounding pixels of the reference pixel, based on a plurality of statistical models, Statistical model selecting means for selecting, and arithmetic decoding means for decoding the encoded data based on the selected statistical model to obtain a binary image of the target block An image decoding apparatus characterized by comprising a.

According to a second aspect of the present invention, the peripheral pixel of the reference pixel is a peripheral pixel located within one pixel range around the reference pixel. It is a decoding device.

According to a third aspect of the present invention, in the image decoding apparatus according to the first aspect, the surrounding pixels of the reference pixel are four pixels located above, below, right and left of the reference pixel. It is.

According to a fourth aspect of the present invention, the statistical model selecting means is configured to determine, based on the state of the peripheral pixel of the target pixel, the state of the peripheral pixel of the target pixel in addition to the state of the reference pixel and the peripheral pixels of the reference pixel. 4. The image decoding device according to claim 1, wherein the image decoding device is a statistical model selecting unit that selects a statistical model from a plurality of statistical models.

According to a fifth aspect of the present invention, in the image decoding apparatus according to the fourth aspect, the peripheral pixels of the target pixel are located above, left, upper left and upper right of the target pixel. Device.

According to a sixth aspect of the present invention, there is provided an image decoding method for decoding encoded data obtained by encoding a binary image for each block to obtain a binary image of a target block. A reference binary image generating step of obtaining a reference binary image from a frame decoded earlier than a target frame having the target block as a target, and a reference block obtaining a reference block including a plurality of pixels from the reference binary image Generating a statistical model based on a state of a reference pixel corresponding to a target pixel in the target block in the reference block and a state of pixels surrounding the reference pixel, and selecting a statistical model from a plurality of statistical models; A selecting step, and an arithmetic decoding step of decoding the encoded data based on the selected statistical model to obtain a binary image of the target block. An image decoding method characterized by comprising the flop.

According to a seventh aspect of the present invention, the peripheral pixel of the reference pixel is a peripheral pixel located within one pixel range around the reference pixel. This is a decoding method.

The present invention according to claim 8 is the image decoding method according to claim 6, wherein the surrounding pixels of the reference pixel are four pixels located above, below, right and left of the reference pixel. It is.

According to a ninth aspect of the present invention, in the statistical model selecting step, in addition to a state of the reference pixel and a state of a pixel surrounding the reference pixel, a state of the peripheral pixel of the target pixel is determined. 9. The image decoding method according to claim 6, further comprising a statistical model selecting step of selecting a statistical model from a plurality of statistical models.

According to a tenth aspect of the present invention, the peripheral pixels of the target pixel are located above, left, and upper left of the target pixel.
10. The image decoding method according to claim 9, wherein the image decoding method is positioned at the upper right.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 is a block diagram showing a configuration of an image coding apparatus according to an embodiment of the present invention. In FIG. 1, a blocking unit 1 (101) is a unit that receives an image to be coded as an input, and divides the input image into blocks including a plurality of pixels. Blocking means 2
(102) is a means for dividing a reference image obtained in advance into blocks consisting of a plurality of pixels. The exclusive-OR block structuring means (103) includes the blocking means 1 (10
Target block divided by 1) and blocking means 2
This means scans the reference block divided by (102), calculates an exclusive OR of the pixel values, and configures an exclusive OR block. Exclusive OR coding means (104)
Is means for encoding an exclusive OR block and outputting encoded data.

The operation of the image coding apparatus according to the present embodiment having the above-described configuration will be described below, and the operation of the image coding method according to an embodiment of the present invention will be described at the same time.

That is, the mask moving image (19
01), the t + 1-th frame (1903) is set as a target binary image, and the t-th frame (1902) is set as a reference binary image. Hereinafter, in the figure, 1 is represented by black and 0 is represented by white. Like the target divided image (1905), the target binary image (1903) is divided into 8 pixels ×
It is divided into a target block of 8 pixels. Blocking means 1
(101) is not limited to the division of 8 pixels × 8 pixels or 16 pixels × 16 pixels.

The reference binary image (1902) is divided into 8 × 8 pixel reference blocks by the blocking means 2 (102) like the reference divided image (204). In the blocking means 2 (102), 8 pixels × 8 pixels or 16 pixels
It is not limited to the division of pixels × 16 pixels.

The target block (2002) in FIG. 20 is one of the blocks in the target divided image (1905).
The reference block (2001) is the target block (2002)
Is a block in the reference divided image (1904) corresponding to. The target block (2002) and the reference block (200)
1) is scanned from the upper left to the lower right, the exclusive OR of the pixel values is calculated, and the exclusive OR block (2003) is configured. An exclusive OR block (200
3) is encoded by the exclusive OR encoding means (104) using a method generally called arithmetic encoding.
The arithmetic coding is briefly described below (see “International Standard for Multimedia Coding”, Chapter 3, Arithmetic Coding, Hiroshi Yasuda, Maruzen Co., Ltd.).

FIG. 21 is a diagram for explaining the principle of arithmetic coding. In arithmetic coding, a symbol sequence (2105),
According to the symbol occurrence probability model (2104), the number line from 0 to 1 (210
1), and the range (210
Shortest binary point (2103) that does not deviate from 2)
Is output as encoded data.

FIG. 22 shows a flowchart of arithmetic coding. At 2201, arithmetic coding is started. At 2202, the range is initialized from 0 to 1. In step 2203, a symbol is input. At 2204, an occurrence probability model is assigned to the current range, and the range of the probability of the input symbol is set as a new range. At 2205, if the symbol is an end symbol,
At 2206, the range is represented by a binary point and the binary point is output, and at 2207, the arithmetic coding is terminated. At 2205,
If the symbol is not the end symbol, the next symbol is input at 2203. However, if the number of symbols is determined, the end symbol can be omitted.

Decoding is performed by determining a symbol sequence from a binary point. It is known that the arithmetic coding has such a property that the more the symbol and the occurrence probability model of the symbol match, and the more the occurrence probability of the symbol is biased, the more the code amount of the symbol sequence decreases. . It is also known that even if the occurrence probability model is changed during encoding, decoding can be performed if the way of the change is known.

The exclusive OR coding means (104) performs the arithmetic coding described above and converts [0, 0.9) to the symbol 0,
Using an occurrence probability model in which [0.9, 1.0) is a symbol 1, a code string of an exclusive OR block that is a symbol string of 0 and 1 is generated, and code data is output.

As described above, in the present embodiment, in the case of a mask moving image, the occurrence probability of the symbol 0 and the symbol 1 of the exclusive OR of the target block and the reference block is approximately 9: 1. By using exclusive OR and combining arithmetic coding, efficient coding with a small code amount is possible. (Embodiment 2) FIG. 2 is a block diagram showing a configuration of an image decoding apparatus according to an embodiment of the present invention. The configuration of this embodiment will be described with reference to FIG. In FIG. 1, an exclusive OR decoding means (201) is a means for receiving encoded data as input and decoding the decoded data to obtain an exclusive OR block.
The blocking unit 2 (202) is a unit that divides a previously obtained reference image into reference blocks each including a plurality of pixels. The target block forming unit (203) is a unit that obtains a target block from the exclusive OR block obtained by the exclusive OR decoding unit (201) and the reference block obtained by the blocking unit (202).

The operation of the image decoding apparatus of the present embodiment configured as described above will be described below, and the operation of one embodiment of the image decoding method of the present invention will be described at the same time.

That is, exclusive OR decoding means (201)
Are the same as [0, 0.
9) is an arithmetic coding type decoder having an occurrence probability model in which symbol 0 is symbol 0 and [0.9, 1.0) is symbol 1. A symbol sequence is generated from a binary point, which is code data, and an occurrence probability model, and symbols are arranged in the scanning direction to form an exclusive OR block.

The blocking means 2 (202) is equivalent to the blocking means 2 (102). The target block forming means (203) scans the exclusive OR block and the reference block, and inverts the pixel value of the reference block for the pixel of which the exclusive OR block is 1, thereby obtaining the target block.

As described above, in the present embodiment, in the case of a mask moving image, the occurrence probability of the symbol 0 and the symbol 1 of the exclusive OR of the target block and the reference block is approximately 9: 1. By using exclusive OR and combining arithmetic coding, efficient decoding with a small code amount is possible. (Embodiment 3) FIG. 3 is a block diagram showing a configuration of an image encoding apparatus according to an embodiment of the present invention. The configuration of the present embodiment will be described with reference to FIG. In the figure, a blocking unit 1 (301) is a unit that receives an image to be encoded as an input, and divides the input image into blocks including a plurality of pixels. The motion estimation means (305)
This is a means for searching for a block similar to the target block from the reference image and obtaining the motion vector. The motion compensation blocking unit 2 (302) is a unit that receives a reference image and motion information and divides the input reference image into blocks composed of a plurality of pixels based on the motion information. The exclusive OR block constructing means (303) includes the blocking means 1 (3
01) scans the target block divided by the motion compensation block forming unit 2 (302) and the reference block divided by the motion compensation block generation unit 2 (302), calculates the exclusive OR of the pixel values, and configures the exclusive OR block. The exclusive OR encoding means (304) encodes the exclusive OR block and outputs encoded data.

The operation of the image coding apparatus according to the present embodiment configured as described above will be described below, and the operation of the image coding method according to an embodiment of the present invention will be described at the same time.

First, the blocking means 1 (301) is equivalent to the blocking means 1 (101). The motion estimating means (305) calculates the motion vector to be estimated as v, the number of pixels in the target block as m, and the position of each pixel in the image as u_i (i
Is 1 to m), and the pixel value at the position x in the target image is A
(X), assuming that the pixel value at the position x in the reference image is B (x), v is used to minimize the similarity s (v) using (Equation 1).
Is detected from a predetermined range, and v is output as a motion vector.

[0034]

(Equation 1) The motion compensation blocker (302) shifts the block cut out from the reference image by the motion vector v to obtain and output the reference block. The exclusive OR block forming means (303) is an exclusive OR block forming means (103).
Is equivalent to The exclusive OR coding means (304) is equivalent to the exclusive OR coding means (104).

As described above, according to the present embodiment, the occurrence probabilities of the symbols 0 and 1 of the exclusive OR block are calculated using the motion estimating means and the motion compensation blocking means.
Motion compensation is performed on blocks that are significantly different from 9: 1 so as to be close to 9: 1, and efficient coding with a small code amount can be performed. (Embodiment 4) FIG. 4 is a block diagram showing a configuration of an image decoding apparatus according to an embodiment of the present invention. The configuration of the present embodiment will be described with reference to FIG. In the figure, an exclusive OR decoding means (401) is a means for receiving coded data as input and decoding it to obtain an exclusive OR block.
The motion compensation blocking unit 2 (402) is a unit that receives a reference image and motion information and divides the input reference image into blocks composed of a plurality of pixels based on the motion information. The target block forming means (403) is a means for obtaining a target block from the exclusive OR block obtained by the exclusive OR decoding means (401) and the reference block obtained by the motion compensation blocking means (402). is there.

The operation of the image decoding apparatus according to this embodiment configured as described above will be described below, and the operation of one embodiment of the image decoding method of the present invention will be described at the same time.

That is, exclusive OR decoding means (401)
Is equivalent to the exclusive OR decoding means (201). The motion compensation blocking unit 2 (402) is equivalent to the motion compensation blocking unit 2 (302). The target block configuration unit (403) is equivalent to the target block configuration unit (203).

As described above, according to the present embodiment, the occurrence probabilities of the symbols 0 and 1 of the exclusive OR block are calculated using the motion estimating means and the motion compensation blocking means.
Blocks that are significantly different from 9: 1 are motion compensated so as to be close to 9: 1, and efficient decoding with a small code amount can be performed. (Embodiment 5) FIG. 5 is a block diagram showing the configuration of an image coding apparatus according to an embodiment of the present invention. The configuration of the present embodiment will be described with reference to FIG.

In the figure, the blocking means 1 (50
1) is a unit that receives an image to be encoded as an input and divides the input image into blocks including a plurality of pixels. The blocking unit 2 (502) is a unit that receives a reference image and divides the input reference image into blocks each including a plurality of pixels. Exclusive OR block construction means (5
03) scans the target block divided by the blocking unit 1 (501) and the reference block divided by the blocking unit 2 (502), calculates the exclusive OR of the pixel values, and calculates the exclusive OR block. Means. The exclusive OR encoding means (504) encodes the exclusive OR block and outputs encoded data. The reference block use determination unit (505) is a unit that compares the target block with the reference block, outputs a reference block use determination signal, and switches the subsequent processing. The target pixel coding unit (506) is a unit that codes the target block and outputs coded data.

The operation of the image coding apparatus according to the present embodiment configured as described above will be described below, and the operation of the image coding method according to an embodiment of the present invention will be described at the same time.

First, the blocking means 1 (501) is equivalent to the blocking means 1 (101). Blocking means 2 (502) is equivalent to blocking means 2 (102). The reference block use determining means (505) uses the sum of absolute values (SAD) of the target block and the reference block, and if the sum of absolute values is equal to or greater than a certain threshold value, encodes using the target pixel coding means (506). If the sum is less than a certain threshold, switching is performed using the exclusive OR block forming means (503) and the exclusive OR coding means (504), and a reference block use determination signal is output. As the threshold value, 5 is used. The exclusive OR block forming means (503) is an exclusive OR block forming means (103).
Is equivalent to The exclusive OR coding means (504) is equivalent to the exclusive OR coding means (104). The target pixel encoding unit (506) is an exclusive OR encoding unit (50).
4), the input is the target block, and [0,
This is an arithmetic encoder using an occurrence probability model in which 0.5) is a symbol 0 and [0.5, 1.0) is a symbol 1.

As described above, according to the present embodiment, a block whose occurrence probability of symbol 0 and symbol 1 is significantly different from that of 9: 1 by the reference block use determination means is a block having a large absolute value sum. Thinking, by changing the coding method, reduce the blocks with poor coding efficiency,
Efficient encoding with a small code amount can be performed. (Embodiment 6) FIG. 6 is a block diagram showing a configuration of an image decoding apparatus according to an embodiment of the present invention. The configuration of the present embodiment will be described with reference to FIG. In the figure, an exclusive OR decoding means (601) is a means for receiving coded data as input and decoding to obtain an exclusive OR block.
Blocking means 2 (602) receives a reference image as input,
This is a means for dividing the input reference image into reference blocks each including a plurality of pixels. Target block configuration means (603)
Is a means for obtaining a target block from the exclusive OR block obtained by the exclusive OR decoding means (601) and the reference block obtained by the blocking means (602). The reference block use control means (604) is a means for switching the subsequent processing according to the reference block use determination signal. The target pixel decoding means (605) is a means for decoding encoded data to obtain a target block.

The operation of the image decoding apparatus having the above-described configuration according to the present embodiment will be described below, and the operation of the image decoding method according to an embodiment of the present invention will be described at the same time.

That is, exclusive OR decoding means (601)
Is equivalent to the exclusive OR decoding means (201). The blocking unit 2 (602) is a blocking unit 2 (10
It is equivalent to 2).

The target block forming means (603) is equivalent to the target block forming means (203). Based on the reference block use determination signal, the reference block use control means (604) performs exclusive OR decoding with the target block forming means (603) and the blocking means 2 (602) when using the reference block in the subsequent processing. It is switched between the case of the decoding unit (601) and the case of the target pixel decoding unit (605) when the reference block is not used.

The target pixel decoding means (605) generates an occurrence probability model using [0, 0.5) as a symbol 0 and [0.5, 1.0) as a symbol 1 as in the target pixel coding (506). Which is a decoder of the arithmetic coding system. A symbol sequence is generated from a binary point, which is code data, and an occurrence probability model, and symbols are arranged in the scanning direction to form a target block.

As described above, according to the present embodiment, a block whose occurrence probability of symbol 0 and symbol 1 is significantly different from that of 9: 1 by the reference block use determining means is a block having a large absolute value sum. Thinking, by changing the coding method, reduce the blocks with poor coding efficiency,
Efficient decoding with a small code amount becomes possible. (Embodiment 7) FIG. 7 is a block diagram showing a configuration of an image coding apparatus according to an embodiment of the present invention. The configuration of the present embodiment will be described with reference to FIG. In the figure, a blocking unit 1 (701) is a unit that receives an image to be encoded and divides the input image into blocks composed of a plurality of pixels.

The blocking unit 2 (702) receives a reference image and divides the input reference image into blocks each including a plurality of pixels. Statistical model selection means (7
03) is the position of the encoding target pixel, the reference block,
A means for receiving a statistical model table, which will be described later, as input, selecting a statistical model from the statistical model table (704) according to the state of surrounding pixels in the reference block of the target pixel, and outputting the selected statistical model to the entropy coding means (705). That is,
The statistical model selecting unit 703 is a unit that selects a statistical model from a plurality of statistical models in a reference block including a reference pixel corresponding to the target pixel in the target block, based on the state of pixels surrounding the reference pixel. The entropy encoding unit (705) outputs the position of the encoding target pixel to the statistical model selection unit (703), and entropy-encodes the target block based on the statistical model output from the statistical model selection unit (703). It is means for outputting encoded data.

The operation of the image coding apparatus according to this embodiment configured as described above will be described below, and the operation of an embodiment of the image coding method according to the present invention will be described at the same time.

First, the blocking means 1 (701) is equivalent to the blocking means 1 (101). Blocking means 2 (702) is equivalent to blocking means 2 (102).

The statistical model selecting means (703) selects a statistical model from a plurality of statistical models and outputs the selected statistical model to the entropy coding means (705). As shown in FIGS. 23 to 26, the statistical model table (2301) is a table in which an index is assigned to each state of surrounding pixels in a reference block of a target pixel, and a statistical model is assigned to each index. The correspondence between each state and the index will be described with reference to FIGS.

Since the surrounding state is considered, first, the reference block (2401) is extrapolated to create an extrapolated reference block. In the creation method, if a surrounding pixel value is obtained from the reference image, it is added to create an extrapolated reference block (2402).

If not obtained, the extrapolated reference block (2403) is created by adding the end pixels as they are. Similarly, an extrapolation target block is created from the target block. The state of the surrounding pixels in the reference block of the target pixel is shown in FIG.
As shown in 8, the reference block (2501) is obtained by applying the reference mask (2503) to the target block (2502) by applying the target mask (2504). Reference mask (250
The pixel values at the respective positions of 3) and the target mask (2504) are represented by A, B, C, D, E, F, G, H, I, J,
Assuming K, L, and M, the index i is represented by (Equation 2). FIG. 28 shows reference pixels 2501a corresponding to the target pixels 2502a. In addition, the statistical model selecting unit 703 of the present embodiment uses the extrapolation target block created above to take into account the state of the neighboring pixels of the already encoded target pixel 2502a in the target block. In the same manner as described above, the target pixel 2502
The state of the neighboring pixel of a is obtained. This makes it possible to select a more appropriate statistical model as compared to a case where only the state of surrounding pixels in the reference block is used. Of course, a configuration using only the state of surrounding pixels in the reference block may be used.

[0054]

(Equation 2) At this time, the statistical model of the index i of the statistical model table (2301) is selected.

As described above, the statistical model selecting means (70)
In 3), a statistical model is selected from the statistical model table and output to the entropy coding means (705). The entropy coding unit (705) uses an arithmetic coder like the exclusive OR coding unit (104).
As the occurrence probability model of the arithmetic encoder, the target pixel is encoded using the statistical model (704) selected by the statistical model selecting means (703).

As described above, according to the present embodiment, since the statistical model is switched by the statistical model selecting means depending on the state of the surrounding pixels in the reference block of the target pixel, the entropy encoding efficiency is increased, and Efficient coding with a small amount becomes possible. (Eighth Embodiment) FIG. 8 is a block diagram showing a configuration of an image decoding apparatus according to an embodiment of the present invention. The configuration of the present embodiment will be described with reference to FIG.

In the figure, the blocking means 2 (80
2) means for receiving a reference image as input and dividing the input reference image into blocks composed of a plurality of pixels. The statistical model selecting means (803) determines the position of the pixel to be encoded,
The reference block and the statistical model table are input, a statistical model is selected from the statistical model table (704) according to the state of pixels surrounding the reference block of the target pixel, and the selected statistical model is output to the entropy coding unit (705). The entropy decoding unit (801) is a unit that receives encoded data, decodes the encoded data based on a statistical model (804), and obtains a target block.

The operation of the image decoding apparatus according to this embodiment having the above-described configuration will be described below, and the operation of the image decoding method according to an embodiment of the present invention will be described at the same time.

First, the blocking means 2 (802) is equivalent to the blocking means 2 (102). The statistical model selecting means (803) is equivalent to the statistical model selecting means (703).

In the entropy decoding means (801),
An arithmetic code decoder is used in the same manner as the exclusive OR decoding means (201), but the statistical model (804) selected by the statistical model selecting means (803) is used as an occurrence probability model of the arithmetic encoder. . Statistical model table (80
4) is equivalent to the statistical model table (704).

As described above, according to the present embodiment, the statistical model selecting means switches and uses the statistical model in the state of the surrounding pixels in the reference block of the target pixel. An efficient decoding with a small amount becomes possible. (Embodiment 9) FIG. 9 is a block diagram showing a configuration of an image coding apparatus according to an embodiment of the present invention. The configuration of the present embodiment will be described with reference to FIG.

In the figure, the blocking means 1 (90
1) is a unit that receives an image to be encoded as an input and divides the input image into blocks including a plurality of pixels. The motion estimating means (906) is a means for searching the reference image for a block similar to the target block and obtaining a motion vector thereof. Motion compensation blocking means 2 (90
2) means for receiving a reference image and motion information as input, and dividing the input reference image into blocks composed of a plurality of pixels based on the motion information. Statistical model selection means (903)
Receives a position of an encoding target pixel, a reference block, and a statistical model table, selects a statistical model from the statistical model table (904) according to the state of pixels surrounding the reference block of the target pixel, and performs entropy encoding ( 90
5) means for outputting. The entropy coding means (905) is means for entropy coding the target block based on the statistical model selected by the statistical model selecting means (903) and outputting coded data.

The operation of the image coding apparatus according to the present embodiment configured as described above will be described below, and the operation of the image coding method according to an embodiment of the present invention will be described at the same time.

First, the blocking means 1 (901) is equivalent to the blocking means 1 (101). The motion estimating means (906) is equivalent to the motion estimating means (305).
The motion compensation blocking unit 2 (902) is equivalent to the motion compensation blocking unit 2 (302).

The statistical model selecting means (903) is equivalent to the statistical model selecting means (703). The statistical model table (904) is equivalent to the statistical model table (704). The entropy coding means (905) is equivalent to the entropy coding means (705).

As described above, according to the present embodiment, it is possible to increase the accuracy of the statistical model and to perform efficient encoding with a small code amount by using the motion estimating means and the motion compensation blocking means. (Embodiment 10) FIG. 10 is a block diagram showing a configuration of an image decoding apparatus according to an embodiment of the present invention. The configuration of the present embodiment will be described with reference to FIG.

In the figure, the motion compensation blocking means 2
(1002) is a unit that receives a reference image and motion information and divides the input reference image into blocks composed of a plurality of pixels based on the motion information. The statistical model selection means (1003) receives the position of the encoding target pixel, the reference block, and the statistical model table as input, and selects a statistical model from the statistical model table (1004) according to the state of pixels surrounding the reference block of the target pixel. And output to the entropy coding means (1005). The entropy decoding unit (1001) is a unit that receives encoded data, decodes the encoded data based on a statistical model, and obtains a target block.

The operation of the image decoding apparatus according to the present embodiment configured as described above will be described below, and the operation of one embodiment of the image decoding method of the present invention will be described at the same time.

That is, the motion compensation blocking means 2 (100
2) is equivalent to the motion compensation blocking unit 2 (402). The statistical model selecting means (1003) is equivalent to the statistical model selecting means (803). In the entropy decoding means (1001), the entropy decoding means (80
It is equivalent to 1). Statistical model table (1004)
Is equivalent to the statistical model table (704).

As described above, according to the present embodiment, the accuracy of the statistical model can be increased using the motion compensation blocking means 2, and efficient decoding with a small code amount can be performed. (Embodiment 11) FIG. 11 is a block diagram showing the configuration of an image coding apparatus according to an embodiment of the present invention. The configuration of the present embodiment will be described with reference to FIG.

In the figure, the blocking means 1 (110
1) is a unit that receives an image to be encoded as an input and divides the input image into blocks including a plurality of pixels.

The blocking unit 2 (1102) is a unit that receives a reference image and divides the input reference image into blocks composed of a plurality of pixels. The statistical model selecting means (1103) receives the position of the encoding target pixel, the reference block, and the statistical model table as input, and selects a statistical model from the statistical model table (1104) according to the state of the pixels surrounding the reference block of the target pixel. And output to the entropy coding means (1105). The reference block use determination unit (1105) is a unit that compares the target block with the reference block, outputs a reference block use determination signal, and switches the subsequent processing. The target pixel encoding unit (1106) is a unit that encodes the target block and outputs encoded data. The entropy coding means (1105) is based on the statistical model (1104)
This is a means for entropy-encoding the target block and outputting encoded data. Target pixel encoding means (1106)
Is means for encoding the target block and outputting encoded data.

The operation of the image coding apparatus of the present embodiment configured as described above will be described below, and the operation of one embodiment of the image coding method of the present invention will be described at the same time.

First, the blocking means 1 (1101)
It is equivalent to the blocking means 1 (101). Blocking means 2 (1102) is equivalent to blocking means 2 (102). The statistical model selection means (1103) is equivalent to the statistical model selection (703). The statistical model table (1104) is equivalent to the statistical model table (704). The entropy coding means (1105) is equivalent to the entropy coding means (705). The reference block use determining means (1106) is equivalent to the reference block use determining means (505). The target pixel decoding means (1107) is equivalent to the target pixel decoding means (605).

As described above, according to the present embodiment, the blocks that do not fit the statistical model are changed by the reference block use control means to reduce the blocks with poor coding efficiency by changing the coding method, and An efficient decoding with a small amount becomes possible. (Embodiment 12) FIG. 12 is a block diagram showing a configuration of an image decoding apparatus according to an embodiment of the present invention. The configuration of the present embodiment will be described with reference to FIG.

In the figure, the blocking means 2 (120
2) means for receiving a reference image as input and dividing the input reference image into blocks composed of a plurality of pixels. The statistical model selecting means (1203) receives the position of the encoding target pixel, the reference block, and the statistical model table as inputs,
This is a means for selecting a statistical model from the statistical model table (1204) according to the state of surrounding pixels of the reference block of the target pixel and outputting the selected statistical model to the entropy coding means (1205). An entropy decoding unit (1201) is a unit that receives encoded data, decodes the encoded data based on a statistical model, and obtains a target block. The reference block use determination unit (1205) is a unit that compares the target block with the reference block and switches the subsequent processing.
The target pixel decoding means (605) is a means for decoding encoded data to obtain a target block.

The operation of the image decoding apparatus according to the present embodiment configured as described above will be described below, and the operation of one embodiment of the image decoding method of the present invention will be described at the same time.

First, the entropy decoding means (120
1) is equivalent to the entropy decoding means (801). Blocking means 2 (1202) is equivalent to blocking means 2 (102). Statistical model selection means (12
03) is equivalent to the statistical model selecting means (703). The statistical model table (1204) is equivalent to the statistical model table (704). The reference block use control means (1205) is a reference block use control means (60).
It is equivalent to 4). Target pixel decoding means (1206)
Is equivalent to the target pixel decoding means (605).

As described above, according to the present embodiment, the blocks that do not fit the statistical model are changed by the reference block use control means to reduce the blocks with poor coding efficiency by changing the coding method, and An efficient decoding with a small amount becomes possible. (Embodiment 13) FIG. 13 is a block diagram showing a configuration of an image coding apparatus according to an embodiment of the present invention. The configuration of the present embodiment will be described with reference to FIG.

In the figure, the blocking means 1 (130
1) is a unit that receives an image to be encoded as an input and divides the input image into blocks including a plurality of pixels. The blocking unit 2 (1302) is a unit that receives a reference image and divides the input reference image into blocks composed of a plurality of pixels. Statistical model estimating means (130
3) means for estimating the statistical model of the target block from the reference block and storing it in the statistical model (1304). The entropy coding unit (1305) is a unit that codes pixels of the target block based on the statistical model (1304) and outputs coded data.

The operation of the image coding apparatus of the present embodiment configured as described above will be described below, and the operation of one embodiment of the image coding method of the present invention will be described at the same time.

That is, the blocking means 1 (1301)
It is equivalent to the blocking means 1 (101). Blocking means 2 (1302) is equivalent to blocking means 2 (102). The statistical model estimating means (1303) estimates a statistical model from the reference block. FIG. 29 is an explanatory diagram of a statistical model estimating method of the statistical model estimating means (1303).

In the statistical model estimation, first, the frequency Z of the symbol 0 is obtained. The frequency Z is obtained by counting the number of symbols 0 in the reference block and dividing the number by the total number of pixels 64. Frequency Z
From the conversion probability (260)
Use 1). In the conversion graph, r = 0.1. The statistical model for estimating using the occurrence probability z obtained from the conversion graph converts [0, z) into symbols 0, [z,
1.0) is symbol 1. The estimated statistical model is stored in the statistical model (1304).

The entropy coding means (1305)
Similarly to the entropy coding means (102), the current block is coded using the statistical model (1304) estimated as an arithmetic coder.

As described above, according to the present embodiment, the statistical model estimating means estimates the statistical model of the symbol in the target block from the reference block, thereby increasing the entropy coding efficiency and increasing the code amount. Less efficient encoding is possible.

In the present embodiment, the configuration is such that a statistical model is generated for each target block. However, the present invention is not limited to this. For example, a configuration for generating a statistical model for each target pixel may be used. (Embodiment 14) FIG. 14 is a block diagram showing a configuration of an image decoding apparatus according to an embodiment of the present invention. The configuration of the present embodiment will be described with reference to FIG.

In the figure, the blocking means 2 (140
2) means for receiving a reference image as input and dividing the input reference image into blocks composed of a plurality of pixels. The statistical model estimating means (1403) estimates a statistical model of the target block from the reference block, and
This is a means for storing the information. The entropy decoding unit (1401) is a unit that receives encoded data, decodes the encoded data based on a statistical model (1404), and obtains a target block.

The operation of the image decoding apparatus according to the present embodiment configured as described above will be described below, and the operation of one embodiment of the image decoding method of the present invention will be described at the same time.

That is, the blocking means 2 (1402)
This is equivalent to the blocking means 2 (102). The statistical model estimating means (1403) includes a statistical model estimating means (130).
It is equivalent to 3). Entropy decoding means (140
1), like the exclusive-OR decoding means (201), decode using the arithmetic code decoder and the statistical model (1404) estimated by the statistical model estimating means (1403),
Get the target block.

As described above, according to the present embodiment, the statistical model estimating means estimates the statistical model of the symbol in the target block from the reference block, thereby increasing the entropy coding efficiency and reducing the code amount. Less efficient decoding is possible. (Embodiment 15) FIG. 15 is a block diagram showing a configuration of an image coding apparatus according to an embodiment of the present invention. The configuration of the present embodiment will be described with reference to FIG.

In the figure, the blocking means 1 (150
1) is a unit that receives an image to be encoded as an input and divides the input image into blocks including a plurality of pixels. The motion estimating means (1506) is a means for searching the reference image for a block similar to the target block and obtaining a motion vector.

Motion Compensation Blocking Means 2 (1502)
Is means for inputting a reference image and motion information, and dividing the input reference image into blocks composed of a plurality of pixels based on the motion information. Statistical model estimation means (1503)
Is means for estimating the statistical model of the target block from the reference block and storing it in the statistical model (1504). The entropy coding unit (1505) is a unit that codes pixels of the target block based on the statistical model (1504) and outputs coded data.

The operation of the image coding apparatus according to the present embodiment configured as described above will be described below, and the operation of the image coding method according to an embodiment of the present invention will be described at the same time.

That is, the blocking means 1 (1501)
It is equivalent to the blocking means 1 (101). The motion compensation blocking means 2 (1502) is equivalent to the motion compensation blocking means 2 (302). Statistical model estimation means (1
504) is equivalent to the statistical model estimating means (1303). The entropy coding means (1503) is equivalent to the entropy coding means (1305). The motion estimating means (1506) is equivalent to the motion estimating means (305).

As described above, according to the present embodiment, the statistical model estimation accuracy is improved by using the motion estimation means and the motion compensation blocking means, and efficient encoding with a small code amount can be performed. (Embodiment 16) FIG. 16 is a block diagram showing a configuration of an image decoding apparatus according to an embodiment of the present invention. The configuration of the present embodiment will be described with reference to FIG.

In the figure, the motion compensation blocking means 2
(1602) is a unit that receives a reference image and motion information and divides the input reference image into blocks composed of a plurality of pixels based on the motion information. The statistical model estimating means (1603) is a means for estimating the statistical model of the target block from the reference block and storing it in the statistical model (1604). Entropy decoding means (1601)
Takes encoded data as input and uses a statistical model (1604)
Is a means for decoding the encoded data and obtaining the target block based on.

The operation of the image decoding apparatus of the present embodiment configured as described above will be described below, and the operation of one embodiment of the image decoding method of the present invention will be described at the same time.

That is, the motion compensation blocking means 2 (160
2) is equivalent to the motion compensation blocking unit 2 (402). The statistical model estimating means (1603) is equivalent to the statistical model estimating means (1303). The entropy decoding unit (1601) is an entropy decoding unit (14).
01).

As described above, according to the present embodiment, the estimation accuracy of the statistical model is increased by using the motion compensation blocking means 2, and efficient decoding with a small code amount becomes possible. (Embodiment 17) FIG. 17 is a block diagram showing a configuration of an image coding apparatus according to an embodiment of the present invention. The configuration of the present embodiment will be described with reference to FIG.

In the figure, the blocking means 1 (170
1) is a unit that receives an image to be encoded as an input and divides the input image into blocks including a plurality of pixels. The blocking unit 2 (1702) is a unit that receives a reference image and divides the input reference image into blocks each including a plurality of pixels. Statistical model estimation means (170
3) means for estimating the statistical model of the target block from the reference block and storing it in the statistical model (1704). The entropy decoding means (1701) receives encoded data as input and, based on a statistical model (1704),
This is a means for decoding encoded data to obtain a target block. The reference block use determination unit (1706) is a unit that compares the target block and the reference block, outputs a reference block use determination signal, and switches the subsequent processing.

The operation of the image coding apparatus according to the present embodiment configured as described above will be described below, and the operation of the image coding method according to an embodiment of the present invention will be described at the same time.

That is, the blocking means 1 (1701)
It is equivalent to the blocking means 1 (101). Blocking means 2 (1702) is equivalent to blocking means 2 (102). The statistical model estimating means (1703) is equivalent to the statistical model estimating means (1303). The entropy coding means (1705) is equivalent to the entropy coding means (1305). The reference block use determining means (1706) is a reference block use determining means (505).
Is equivalent to The target pixel decoding means (1707) is equivalent to the target pixel decoding means (605).

As described above, according to the present embodiment, the blocks that do not fit the statistical model are changed by the reference block use control means to reduce the blocks with low coding efficiency by changing the coding method. An efficient decoding with a small amount becomes possible. (Embodiment 18) FIG. 18 is a block diagram showing a configuration of an image decoding apparatus according to an embodiment of the present invention. The configuration of the present embodiment will be described with reference to FIG.

In the figure, the blocking means 2 (180
2) means for receiving a reference image as input and dividing the input reference image into blocks composed of a plurality of pixels. The statistical model estimating means (1803) estimates a statistical model of the target block from the reference block, and obtains a statistical model (1804).
This is a means for storing the information. The entropy decoding unit (1801) is a unit that receives encoded data, decodes the encoded data based on the statistical model (1804), and obtains a target block. The reference block use control means (1805) is a means for switching the subsequent processing according to the reference block use determination signal. The target pixel coding unit (1806) is a unit that codes the target block and outputs coded data.

The operation of the image decoding apparatus according to the present embodiment configured as described above will be described below, and the operation of one embodiment of the image decoding method of the present invention will be described at the same time.

That is, the blocking means 2 (1802)
This is equivalent to the blocking means 2 (102). The statistical model estimating means (1803) includes a statistical model estimating means (130).
It is equivalent to 3). Entropy decoding means (180
1) is equivalent to the entropy decoding means (1401). The reference block use control means (1805) is equivalent to the reference block use control means (604). The target pixel decoding means (1806)
05).

As described above, according to the present embodiment, the blocks that do not fit the statistical model are changed by the reference block use control means to reduce the blocks with poor coding efficiency by changing the coding method. An efficient decoding with a small amount becomes possible.

On the other hand, a magnetic recording medium or an optical recording medium storing a program for causing a computer to execute the functions of all or some of the means described in any one of the above-described embodiments. The same effect as described above can also be obtained by making the computer execute the above operation using this.

As described above, in the image encoding apparatus, the image decoding apparatus, the image encoding method, and the image decoding method of the present invention, the conventional binary image encoding technique, Encoding and decoding can be performed more efficiently than using the image decoding technique. That is, (1) a target image is predicted from a reference image in a binary moving image, and the residual is expressed by an exclusive OR. (2) An appropriate statistical model is always used by switching the statistical model according to the state of surrounding pixels of another correlated frame. (3) By creating a statistical model from a reference image,
Use an appropriate statistical model. (4) Blocks that do not fit the statistical model are reduced by changing the coding method using a threshold value that uses motion compensation or the sum of absolute value differences.

Although the reference block use determining means of the present invention has been described in the fifth embodiment with the configuration shown in FIG. 5, the present invention is not limited to this. For example, the configuration shown in FIG. 30 may be used. That is, in the case of the image encoding device shown in FIG.
The reference block use determination unit 3505 is a unit that compares the coding amount of the target block with the coding amount of the reference block, outputs a reference block use determination signal, and switches the subsequent processing. This is the main difference from the configuration of FIG. As a result, the reference block use determination unit 3505 uses the coding amount of the target image coding unit 506 and the coding amount of the exclusive OR coding unit 504 to perform coding by the target image coding unit 506. If the amount is smaller, the encoded data is output, and if the amount of code in the exclusive OR encoder 504 is smaller, the output is switched to output the encoded data. If the code amount in the target image coding means 506 is smaller, a reference block use determination signal is output. As described above, according to the present embodiment, the reference block use determination unit 3505 uses the code amount as a reference and switches the coded data, thereby reducing blocks with low coding efficiency and reducing the code amount. Less and more efficient encoding is possible. Note that the same reference numerals are given to basically the same components as those in FIG.

In the sixth embodiment, the reference block use control means of the present invention has been described with reference to the configuration shown in FIG. 6. However, the present invention is not limited to this, and may have the configuration shown in FIG. 31, for example. That is, the image decoding apparatus shown in FIG.
Alternatively, based on the target pixel decoding unit 605 that decodes the encoded data output from the image encoding device illustrated in FIG. 30 to obtain a target block, and the reference block use determination signal output from the image encoding device, A reference block use control unit 3604 for outputting an output from the target block forming unit 603 or an output from the target pixel decoding unit 605 as a target block. As a result, more efficient decoding can be performed as compared with the related art. Note that the same reference numerals are given to basically the same components as those in FIG.

In the seventh embodiment, the statistical model selecting means of the present invention has been described in connection with a configuration in which the result of selecting a statistical model is not output to the decoding device side. However, the present invention is not limited to this. As shown in FIG.
A unit 703 may output a selection result of the statistical model as a selection result signal to the decoding device side. FIG. 7
The same reference numerals are given to the same components as those of the first embodiment.

In the eighth embodiment, the image decoding apparatus of the present invention is a decoding apparatus corresponding to an image coding apparatus having a configuration in which the result of selection of the statistical model is not output to the decoding apparatus. Although described above, the present invention is not limited to this. For example, the configuration shown in FIG. 33 may be used. That is, the image decoding apparatus shown in FIG. 33 obtains a selection result signal output from the image encoding apparatus shown in FIG. 32, and selects a statistical model corresponding to the selection result signal from a plurality of statistical models. The image processing apparatus includes a selection unit 3803 and an entropy decoding unit 801 that performs entropy decoding on the encoded data output from the image encoding device based on the selected statistical model to obtain a target block. As a result, more efficient decoding can be performed as compared with the related art. In the case of the present embodiment, the blocking means 2 (802) as shown in FIG.
Is unnecessary. Note that the same reference numerals are given to basically the same components as those in FIG.

In the eleventh embodiment, the reference block use judging means of the present invention has been described with reference to the configuration shown in FIG. 11. However, the present invention is not limited to this. For example, the configuration shown in FIG. That is, in the case of the image coding apparatus shown in FIG. 34, the reference block use determination unit 3106 compares the coding amount of the target block with the coding amount of the reference block,
This is a means for outputting a reference block use determination signal and switching the subsequent processing. This is the main difference from the configuration of FIG. Thereby, the reference block use determining means 3
In 106, using the coding amount of the target image coding unit 1107 and the coding amount of the entropy coding unit 1105, if the coding amount of the target image coding unit 1107 is smaller, the coding is performed. If data is output and the code amount in the entropy coding unit 1105 is smaller, switching is performed so as to output the coded data. If the code amount in the target image coding unit 1107 is smaller, a reference block use determination signal is output. As described above, according to the present embodiment, the reference block use determination unit 31106 uses the code amount as a reference and switches the coded data, thereby reducing blocks with low coding efficiency and reducing the code amount. Less and more efficient encoding is possible. Note that the same reference numerals are given to basically the same components as those in FIG.

In the twelfth embodiment, the reference block use control means of the present invention has been described with reference to the configuration shown in FIG. 12. However, the present invention is not limited to this, and may have a configuration shown in FIG. 35, for example. That is, the image decoding apparatus shown in FIG.
The target pixel decoding unit 1206 that decodes the encoded data output from the image encoding device illustrated in FIG. 11 or 34 to obtain a target block, and the reference block use determination signal output from the image encoding device. A reference block utilization control unit 3205 for outputting the output from the entropy decoding unit 1201 or the output from the target pixel decoding unit 1206 as a target block
This is a configuration including: As a result, more efficient decoding can be performed as compared with the related art. It is to be noted that the same components as those in FIG. 12 are denoted by the same reference numerals.

Also, in the above embodiment, t + 1 of the moving image
Set the frame as the target binary image and refer to the t-th frame.
The case where the image is a value image has been described. However, the present invention is not limited to this. For example, the same object is photographed by a stereo camera, and an image photographed by one camera
It is also possible to use an image taken by the other camera as a reference binary image. Even in this case, the same effect as described above is exerted.

As described above, the first aspect related to the present invention is
According to the technique, a target binary image, which is an image to be coded, is input, the target binary image is divided into blocks including a plurality of pixels, and a blocking unit 1 that obtains a target block is provided. A blocker 2 for dividing the binary image into blocks including a plurality of pixels to obtain a reference block; sequentially scanning the target block and the reference block to detect an exclusive OR of both pixel values; An image encoding apparatus includes: an exclusive OR block forming unit that constitutes a block; and an exclusive OR encoding unit that generates a code string of the exclusive OR and outputs the encoded data as encoded data.

Further, a second technique related to the present invention is a blocking technique that divides a reference binary image obtained in advance into blocks including a plurality of pixels and obtains a reference block. An exclusive-OR decoding means for decoding the encoded data encoded by the image coding apparatus of the technique to obtain an exclusive-OR block, and combining the exclusive-OR block and the reference block to constitute a target block An image decoding apparatus comprising: a target block forming unit.

A third technique related to the present invention is to input a target binary image which is an image to be coded, divide the target binary image into blocks including a plurality of pixels, and obtain a target block. Blocking means 1 and reference 2 obtained in advance
A value dividing unit that divides the value image into blocks including a plurality of pixels and obtains a reference block, based on a state of surrounding pixels of the reference pixel in the reference block including a reference pixel corresponding to the target pixel in the target block; A statistical model selecting means for selecting a statistical model from a plurality of statistical models, and entropy encoding means for entropy encoding the target pixel based on the selected statistical model and outputting encoded data. It is an encoding device.

Further, a fourth technique related to the present invention comprises a dividing means 2 for dividing a previously obtained reference binary image into blocks including a plurality of pixels to obtain a reference block; Statistical model selecting means for selecting a statistical model from a plurality of statistical models, based on a state of pixels surrounding the reference pixel in a reference block including a reference pixel corresponding to the target pixel, based on the selected statistical model , An entropy decoding unit that entropy decodes the encoded data output from the image encoding device according to the third technique to obtain a target block.

Further, according to a fifth technique relating to the present invention, a block most similar to the target block is referred to as the reference 2.
A motion estimating unit that searches from the value image and obtains motion information from the search result, wherein the blocking unit 2 performs motion compensation on the reference binary image with the motion information to obtain a reference block The image encoding device according to the third technique, wherein the image encoding device outputs the motion information.

According to a sixth technique relating to the present invention, the blocking means 2 converts the previously obtained reference binary image into the image output from the image encoding apparatus of the fifth technique. The image decoding apparatus according to the fourth technique, characterized in that the image decoding apparatus is a motion compensation block forming unit 2 that obtains a reference block by performing motion compensation using motion information.

A seventh technique related to the present invention compares the target block with the reference block, and determines whether or not to use the reference block based on the comparison result. A reference block use determining unit that switches the driving of various units; and a target pixel coding unit that generates a coded sequence of pixel values of the target block and outputs the coded data as coded data. When it is determined that the block is used, the entropy coding unit and the statistical model selection unit are driven to output coded data from the entropy coding unit. The pixel encoding means is driven to output encoded data from the target pixel encoding means, and it is determined whether or not to use the reference block. Outputting the reference block usage determination signal is an image coding apparatus of the third technology characterized.

According to an eighth technique relating to the present invention, it is determined whether or not the reference block is to be used, based on a reference block use determination signal output from the image coding apparatus according to the seventh technique. The reference block use control means for switching the driving of the various means thereafter, and target pixel decoding means for decoding the coded data output from the image coding apparatus to obtain a target block, If the control means determines that the reference block is to be used, the entropy decoding means and the statistical model selecting means are driven to output the target block from the entropy decoding means, and if it is determined that the block is not used, Driving the target pixel decoding means to output a target block from the target pixel decoding means.
An image decoding apparatus according to the technique of (1).

A ninth technique related to the present invention is a block which receives a target binary image which is an image to be encoded, divides the target binary image into blocks including a plurality of pixels, and obtains a target block. Means for dividing, a reference binary image obtained in advance into blocks including a plurality of pixels, and a blocking means 2 for obtaining a reference block; and a statistical model generation for generating a statistical model of a target pixel from the reference block. An image encoding apparatus comprising: means; and entropy encoding means for entropy encoding the target pixel based on the generated statistical model and outputting the encoded data as encoded data.

A tenth technique related to the present invention is a blocking means 2 for dividing a reference binary image obtained in advance into blocks including a plurality of pixels to obtain a reference block,
A statistical model generating means for generating a statistical model of the target pixel from the reference block, and entropy decoding of the encoded data output from the image encoding device according to the ninth technique based on the generated statistical model, An image decoding device comprising: an entropy decoding unit for obtaining a block.

An eleventh technique related to the present invention is such that a target binary image which is an
Dividing the value image into blocks including a plurality of pixels to obtain a target block; dividing the reference binary image obtained in advance into blocks including a plurality of pixels to obtain a reference block; And the reference block are sequentially scanned, an exclusive OR of both pixel values is detected, an exclusive OR block is formed, and a code string of the exclusive OR is generated and output as encoded data. Image encoding method provided.

According to a twelfth technique related to the present invention, a reference binary image obtained in advance is divided into blocks each including a plurality of pixels to obtain a reference block.
Inputting the encoded data encoded by the image encoding method of the first technology, decoding the encoded data to obtain an exclusive OR block, synthesizing the exclusive OR block and the reference block, And a step of configuring a target block.

A thirteenth technique related to the present invention is that a target binary image which is an
Step 1 of dividing the value image into blocks including a plurality of pixels to obtain a target block, and Step 2 of dividing a previously obtained reference binary image into blocks including a plurality of pixels to obtain a reference block And, based on the state of the surrounding pixels of the reference pixel in a reference block including a reference pixel corresponding to the target pixel in the target block,
A statistical model selecting step of selecting a statistical model from a plurality of statistical models; and an entropy encoding step of entropy encoding the target pixel based on the selected statistical model and outputting encoded data. Is the way.

According to a fourteenth technique related to the present invention, a reference binary image obtained in advance is divided into blocks including a plurality of pixels, and a block forming step of obtaining a reference block is performed.
A statistical model selecting step of selecting a statistical model from a plurality of statistical models based on a state of pixels surrounding the reference pixel in a reference block including a reference pixel corresponding to the target pixel in the target block; Entropy decoding of the encoded data output by the image encoding method of the thirteenth technique based on the statistical model obtained above to obtain a target block.

A fifteenth technique related to the present invention further comprises a motion estimating step of searching the reference binary image for a block most similar to the target block, and obtaining motion information from the search result. The blocking step 2 is a motion-compensated blocking step 2 for obtaining a reference block by motion-compensating the reference binary image with the motion information, and outputting the motion information according to the thirteenth technique. It is.

According to a sixteenth technique relating to the present invention, in the blocking step 2, the reference binary image obtained in advance is obtained by converting the reference binary image output by the image encoding method of the fifteenth technique. The image decoding method according to the fourteenth technique, which is a motion compensation block forming step 2 of obtaining a reference block by performing motion compensation using motion information.

According to a seventeenth technique related to the present invention, the target block is compared with the reference block, and whether or not the reference block is used is determined based on the comparison result. A reference block use determining step of switching execution of various steps; and a target pixel coding step of generating a coded sequence of pixel values of the target block and outputting the coded data as coded data. When it is determined that the block is used, the entropy coding step and the statistical model selecting step are executed, and the encoded data is output by the entropy coding step. Executing a pixel encoding step, and outputting encoded data in the target pixel encoding step. Is the thirteenth image coding method of the technology and outputs whether the determination result using the reference block as a reference block usage determination signal.

According to an eighteenth technique relating to the present invention, it is determined whether or not to use the reference block based on the reference block use determination signal output by the image coding method of the seventeenth technique. And a target pixel decoding step of decoding the encoded data output by the image encoding method to obtain a target block. If the control step determines that the reference block is to be used, the entropy decoding step and the statistical model selection step are performed, and the target block is output by the entropy decoding step. , Causing the target pixel decoding step to be executed, and The outputting the block first
This is an image decoding method according to the fourth technique.

According to a nineteenth technique related to the present invention, a target binary image, which is an image to be coded, is input, the target binary image is divided into blocks including a plurality of pixels, and a target block is obtained. Dividing a previously obtained reference binary image into blocks including a plurality of pixels to obtain a reference block, generating a statistical model of the target pixel from the reference block, and generating the target pixel. Entropy-encoding based on the obtained statistical model and outputting the encoded data as encoded data.

According to a twentieth technique relating to the present invention, a reference binary image obtained in advance is divided into blocks each including a plurality of pixels to obtain a reference block, and a step of obtaining a target pixel from the reference block is performed. Image decoding comprising the steps of: generating a statistical model; and entropy decoding encoded data output by the image encoding method according to the nineteenth technology based on the generated statistical model to obtain a target block. Method.

As is apparent from the above description, the technique related to the present invention predicts a pixel to be coded from a previously obtained binary image having a high correlation, and encodes the difference to obtain a conventional image. The present invention relates to an image encoding device, an image decoding device, an image encoding method, and an image decoding method capable of encoding / decoding even more efficiently than using the binary image encoding / decoding technology. In addition, there is an advantage that coding and decoding can be performed more efficiently than using a conventional binary image coding technique.

[0138]

As is apparent from the above description, the technology related to the present invention has an advantage that decoding can be performed more efficiently than using the conventional binary image coding technology.

[Brief description of the drawings]

FIG. 1 is a block diagram of an image encoding device according to a first embodiment of the present invention.

FIG. 2 is a block diagram of an image decoding apparatus according to a second embodiment of the present invention.

FIG. 3 is a block diagram of an image encoding device according to a third embodiment of the present invention.

FIG. 4 is a block diagram of an image decoding apparatus according to a fourth embodiment of the present invention.

FIG. 5 is a block diagram of an image encoding device according to a fifth embodiment of the present invention.

FIG. 6 is a block diagram of an image decoding apparatus according to a sixth embodiment of the present invention.

FIG. 7 is a block diagram of an image encoding device according to a seventh embodiment of the present invention.

FIG. 8 is a block diagram of an image decoding apparatus according to an eighth embodiment of the present invention.

FIG. 9 is a block diagram of an image encoding device according to a ninth embodiment of the present invention.

FIG. 10 is a block diagram of an image decoding apparatus according to a tenth embodiment of the present invention.

FIG. 11 is a block diagram of an image encoding device according to an eleventh embodiment of the present invention.

FIG. 12 is a block diagram of an image decoding apparatus according to a twelfth embodiment of the present invention.

FIG. 13 is a block diagram of an image encoding device according to a thirteenth embodiment of the present invention.

FIG. 14 is a block diagram of an image decoding apparatus according to a fourteenth embodiment of the present invention.

FIG. 15 is a block diagram of an image encoding device according to a fifteenth embodiment of the present invention.

FIG. 16 is a block diagram of an image decoding apparatus according to a sixteenth embodiment of the present invention.

FIG. 17 is a block diagram of an image encoding device according to a seventeenth embodiment of the present invention.

FIG. 18 is a block diagram of an image decoding apparatus according to an eighteenth embodiment of the present invention.

FIG. 19 is a diagram of a reference image and a target image in a mask moving image.

FIG. 20 is an explanatory diagram of an exclusive OR block configuration;

FIG. 21 is a diagram illustrating the principle of arithmetic coding.

FIG. 22 is a block diagram of arithmetic coding.

FIG. 23 is a diagram illustrating a part of a statistical model table;

FIG. 24 is a diagram showing a part of a statistical model table;

FIG. 25 is a partial diagram of a statistical model table;

FIG. 26 is a diagram illustrating a part of a statistical model table;

FIG. 27 is an explanatory diagram of an extrapolation reference block.

FIG. 28 is an explanatory diagram of an index of a statistical model table.

FIG. 29 is an explanatory diagram of a frequency-occurrence probability conversion graph.

FIG. 30 is a block diagram of an image encoding device according to another embodiment of the present invention.

FIG. 31 is a block diagram of an image decoding apparatus according to another embodiment of the present invention.

FIG. 32 is a block diagram of an image encoding device according to still another embodiment of the present invention.

FIG. 33 is a block diagram of an image decoding apparatus according to still another embodiment of the present invention.

FIG. 34 is a block diagram of an image encoding device according to still another embodiment of the present invention.

FIG. 35 is a block diagram of an image decoding apparatus according to still another embodiment of the present invention.

[Explanation of symbols]

 101 Blocking Means 1 102 Blocking Means 2 103 Exclusive-OR Block Constructing Means 104 Exclusive-OR Encoding Means 201 Exclusive-OR Decoding Means 202 Blocking Means 2 203 Target Block Constructing Means 301 Blocking Means 1 302 Motion Compensation Block Means 2 303 exclusive OR block forming means 304 exclusive OR coding means 305 motion estimating means 401 exclusive OR decoding means 402 motion compensation blocking means 2 403 target block forming means 501 blocking means 1 502 blocking means 2 503 Exclusive OR block structuring unit 504 Exclusive OR coding unit 505 Reference block use determining unit 506 Target pixel encoding unit 601 Exclusive OR decoding unit 602 Blocking unit 2 603 Target block forming unit 604 Reference block Usage control means 605 Target pixel decoding means 701 Blocking means 1 702 Blocking means 2 703 Statistical model estimating means 704 Statistical model 705 Entropy coding means 801 Entropy decoding means 802 Blocking means 2 803 Statistical model estimating means 804 Statistical model 901 Blocking means 1 902 Motion compensation blocking means 2 903 Statistical model estimating means 904 Statistical model 905 Entropy coding means 906 Motion estimating means 1001 Entropy decoding means 1002 Motion compensation blocking means 2 1003 Statistical model selecting means 1004 Statistical model table 1101 blocking means 1 1102 blocking means 2 1103 statistical model selecting means 1104 statistical model table 1105 entropy coding means 1106 Block use determining means 1107 target pixel coding means 1201 entropy decoding means 1202 blocking means 2 1203 statistical model selecting means 1204 statistical model table 1205 reference block use control means 1206 target pixel decoding means 1301 blocking means 1 1302 blocking means 2 1303 Statistical model estimating means 1304 Statistical model 1305 Entropy coding means 1401 Entropy decoding means 1402 Blocking means 2 1403 Statistical model estimating means 1404 Statistical model 1501 Blocking means 1 1502 Motion compensation blocking means 2 1503 Entropy coding means 1504 Statistical model estimation means 1505 Statistical model 1506 Motion estimation means 1601 Entropy decoding means 1602 Motion compensation block Means 2 1603 Statistical model estimating means 1604 Statistical model 1701 Blocking means 1 1702 Blocking means 2 1703 Statistical model estimating means 1704 Statistical model 1705 Entropy estimating means 1706 Reference block use determining means 1707 Target pixel coding means 1801 Entropy decoding means 1802 Blocking unit 2 1803 Statistical model estimation unit 1804 Statistical model 1805 Reference block use control unit 1806 Target pixel decoding unit 1901 Mask moving image 1902 Reference image 1903 Target image 1904 Reference divided image 1905 Target divided image 2001 Reference block 2002 Target block 2003 Exclusive OR block 2101 Number line 2102 Range 2103 Binary point 2104 Occurrence probability model 2105 Symbol sequence 201 Introduction 2202 Range initialization 2203 Symbol input 2204 Range limitation 2205 End judgment 2206 Binary point output 2207 End 2301 Statistical model table 2401 Reference block 2402 Extrapolation reference block 2403 Extrapolation reference block 2501 Reference block 2502 Target block 2503 Reference mask 2503 Target Mask 2601 conversion graph

Claims (10)

[Claims] An image decoding apparatus for decoding coded data obtained by coding a binary image for each block to obtain a binary image of a target block, comprising: a target having the target block to be decoded. A reference binary image generating means for obtaining a reference binary image from a frame decoded before the frame; a reference block generating means for obtaining a reference block including a plurality of pixels from the reference binary image; Statistical model selecting means for selecting a statistical model from a plurality of statistical models based on a state of a reference pixel corresponding to a target pixel in the certain target block and a state of pixels surrounding the reference pixel; Arithmetic decoding means for decoding the encoded data based on a model to obtain a binary image of the target block. Apparatus. 2. The image decoding apparatus according to claim 1, wherein the peripheral pixels of the reference pixel are peripheral pixels located within one pixel range around the reference pixel. 3. The image decoding apparatus according to claim 1, wherein the surrounding pixels of the reference pixel are four pixels located above, below, right and left of the reference pixel. 4. The statistical model selecting means, in addition to a state of the reference pixel and a state of pixels surrounding the reference pixel,
The image decoding apparatus according to any one of claims 1 to 3, wherein the image decoding apparatus is a statistical model selecting unit that selects a statistical model from a plurality of statistical models based on a state of pixels surrounding the target pixel. 5. The image decoding apparatus according to claim 4, wherein the surrounding pixels of the target pixel are located above, left, upper left, and upper right of the target pixel. 6. An image decoding method for decoding coded data obtained by coding a binary image for each block to obtain a binary image of a target block, comprising: a target having the target block to be decoded. A reference binary image generating step of obtaining a reference binary image from a frame decoded earlier than a frame; a reference block generating step of obtaining a reference block including a plurality of pixels from the reference binary image; A statistical model selecting step of selecting a statistical model from a plurality of statistical models based on a state of a reference pixel corresponding to the target pixel in the certain target block, and a state of pixels surrounding the reference pixel; An arithmetic decoding step of decoding the encoded data based on a model to obtain a binary image of the target block. Picture decoding method according to. 7. The image decoding method according to claim 6, wherein the surrounding pixels of the reference pixel are surrounding pixels located within one pixel range around the reference pixel. 8. The image decoding method according to claim 6, wherein the surrounding pixels of the reference pixel are four pixels located above, below, right and left of the reference pixel. 9. The statistical model selecting step includes, based on a state of the peripheral pixel of the target pixel and a state of the peripheral pixel of the reference pixel, a statistical model from a plurality of statistical models. 9. The image decoding method according to claim 6, further comprising a step of selecting a statistical model to be selected. 10. The image decoding method according to claim 9, wherein the surrounding pixels of the target pixel are located above, left, upper left, and upper right of the target pixel.