EP0435163A2
Expired / Lapsed
EP
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Coding apparatus
Assignee: Mitsubishi Electric Corp
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Filing: 1990-12-20
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Granted: —
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Expires: 2010-12-20
Abstract
Abstract In an image coding apparatus, each block having a plurality of picture elements is divided into a plurality of sub-blocks, and an appropriate quantization step or weighting factor is decided on the basis of the absolute value sum of difference of image signal level between adjacent picture elements in the sub-block, so that digital image data are reduced. Moreover, in an image coding apparatus, each block having a plurality of picture elements is divided into a plurality of sub-blocks, and an appropriate quantization step or weighting factor is decided on the basis of the maximum and minimum values of the image signals of the picture elements in the sub-block, so that digital image data are reduced. It is also provided a coding apparatus equipped with a weighting unit having not more adders than 1/4 of the number of picture elements included in each block. This coding apparatus can perform coding with high efficiency by a small-size weighting unit without causing degradation of image quality.
Inventors
- 👤 Yoshiko C/O Denshi Shohin Kaihatsu Hatano
- 👤 Yoshinori C/O Denshi Shohin Kaihatsu Asamura
- 👤 Ken C/O Denshi Shohin Kaihatsu Onishi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 15:38
CPC Classifications
H; H04; H04N; H04N19/00; H04N19/60; H04N19/649; H04N19/10; H04N19/102; H04N19/124; H04N19/126; H04N19/134; H04N19/136; H04N19/14; H04N19/157; H04N19/16; H04N19/169; H04N19/17; H04N19/176; H04N19/18; H04N19/62; H04N19/90; H04N19/98; H04N19/13; H04N19/146; H04N19/152; H04N19/91
Claims Analysis
Total Claims: 44
Claim 1
Independent Claim
110 words
A coding apparatus for reducing a digital image signal, comprising: block formatting means for dividing said digital image signal into blocks of plurality of picture elements; orthogonal transforming means for performing orthogonal transform on the formatted image signal; quantizing means for quantizing coefficients obtained through the orthogonal transform with a quantization table; means for dividing each block of the image signal outputted from said block formatting means into a plurality of sub-blocks and obtaining criterion values from the absolute value sum of difference of image signal level between adjacent picture elements in said each sub-block; and deciding means for deciding the quantization table on the basis of said criterion values.
Claim 2
Dependent Claim
42 words
A coding apparatus as set forth in Claim 1, wherein said criterion values are representative values of the absolute value sum of difference of image signal level between adjacent picture elements in said each sub-block, and/or values calculated from said representative values.
Claim 3
Dependent Claim
42 words
A coding apparatus as set forth in Claim 2, wherein said criterion values are obtained on the basis of the absolute value sum of difference of image signal level between adjacent picture elements in horizontal and vertical directions in said each sub-block.
Claim 4
Dependent Claim
55 words
A coding apparatus as set forth in Claim 3, wherein said criterion values are the minimum value of the absolute value sum of difference of image signal level between adjacent picture elements in horizontal and vertical directions in said each sub-block, and the difference between the maximum and minimum values of said absolute value sum.
Claim 5
Dependent Claim
43 words
A coding apparatus as set forth in Claim 3, wherein said criterion values are the minimum and maximum values of the absolute value sum of difference of image signal level between adjacent picture elements in horizontal and vertical directions in said each sub-block.
Claim 6
Dependent Claim
64 words
A coding apparatus as set forth in Claim 2, wherein said criterion values are obtained on the basis of the absolute value sum of difference of image signal level between adjacent picture elements in horizontal direction in said each sub-block, and the absolute value sum of difference of image signal level between adjacent picture elements in horizontal and vertical directions in said each sub-block.
Claim 7
Dependent Claim
72 words
A coding apparatus as set forth in Claim 6, wherein said criterion values are the minimum value of the absolute value sum of difference of image signal level between adjacent picture elements in horizontal direction in said each sub-block, and the difference between the maximum and minimum values of the absolute value sum of difference of image signal level between adjacent picture elements in horizontal and vertical directions in said each sub-block.
Claim 8
Dependent Claim
67 words
A coding apparatus as set forth in Claim 6, wherein said criterion values are the minimum value of the absolute value sum of difference of image signal level between adjacent picture elements in horizontal direction in said each sub-block, and the maximum value of the absolute value sum of difference of image signal level between adjacent picture elements in horizontal and vertical directions in said each sub-block.
Claim 9
Dependent Claim
23 words
A coding apparatus as set forth in Claim 2, wherein said criterion values are the average variation quantity of said absolute value sum.
Claim 10
Dependent Claim
43 words
A coding apparatus as set forth in Claim 1, wherein said block formatting means divides said digital image signal into two-dimensional blocks per every field or every frame, and said orthogonal transforming means performs orthogonal transform per every unit of the two-dimensional block.
Claim 11
Dependent Claim
56 words
A coding apparatus as set forth in Claim 1, wherein said block formatting means divides said digital image signal into three-dimensional blocks in horizontal and vertical directions in each field or frame and in time direction in successive fields or frames, and said orthogonal transforming means performs orthogonal transform per every unit of the three-dimensional block.
Claim 12
Dependent Claim
62 words
A coding apparatus as set forth in Claim 1, further comprising: means for performing variable length coding on the quantized coefficients; memory means for storing the variable-length-coded coefficients; and controlling means for detecting the storing amount of said memory means and controlling decision of the quantization table in said deciding means so as to keep said storing amount within a predetermined volume.
Claim 13
Dependent Claim
18 words
A coding apparatus as set forth in Claim 1, wherein said orthogonal transform is DCT (Discrete Cosine Transform).
Claim 14
Dependent Claim
112 words
A coding apparatus for reducing a digital image signal, comprising: block formatting means for dividing said digital image signal into blocks of plurality of picture elements; orthogonal transforming means for performing orthogonal transform on the formatted image signal; weighting means for performing weighting on coefficients obtained through the orthogonal transform with a weighting factor; means for dividing each block of the image signal outputted from said block formatting means into a plurality of sub-blocks and obtaining criterion values from the absolute value sum of difference of image signal level between adjacent picture elements in said each sub-block; and deciding means for deciding the weighting factor on the basis of said criterion values.
Claim 15
Dependent Claim
42 words
A coding apparatus as set forth in Claim 14, wherein said criterion values are representative values of the absolute value sum of difference of image signal level between adjacent picture elements in said each sub-block, and/or values calculated from said representative values.
Claim 16
Dependent Claim
42 words
A coding apparatus as set forth in Claim 15, wherein said criterion values are obtained on the basis of the absolute value sum of difference of image signal level between adjacent picture elements in horizontal and vertical directions in said each sub-block.
Claim 17
Dependent Claim
55 words
A coding apparatus as set forth in Claim 16, wherein said criterion values are the minimum value of the absolute value sum of difference of image signal level between adjacent picture elements in horizontal and vertical directions in said each sub-block, and the difference between the maximum and minimum values of said absolute value sum.
Claim 18
Dependent Claim
43 words
A coding apparatus as set forth in Claim 16, wherein said criterion values are the minimum and maximum values of the absolute value sum of difference of image signal level between adjacent picture elements in horizontal and vertical directions in said each sub-block.
Claim 19
Dependent Claim
64 words
A coding apparatus as set forth in Claim 15, wherein said criterion values are obtained on the basis of the absolute value sum of difference of image signal level between adjacent picture elements in horizontal direction in said each sub-block, and the absolute value sum of difference of image signal level between adjacent picture elements in horizontal and vertical directions in said each sub-block.
Claim 20
Dependent Claim
72 words
A coding apparatus as set forth in Claim 19, wherein said criterion values are the minimum value of the absolute value sum of difference of image signal level between adjacent picture elements in horizontal direction in said each sub-block, and the difference between the maximum and minimum values of the absolute value sum of difference of image signal level between adjacent picture elements in horizontal and vertical directions in said each sub-block.
Claim 21
Dependent Claim
67 words
A coding apparatus as set forth in Claim 19, wherein said criterion values are the minimum value of the absolute value sum of difference of image signal level between adjacent picture elements in horizontal direction in said each sub-block, and the maximum value of the absolute value sum of difference of image signal level between adjacent picture elements in horizontal and vertical directions in said each sub-block.
Claim 22
Dependent Claim
23 words
A coding apparatus as set forth in Claim 15, wherein said criterion values are the average variation quantity of said absolute value sum.
Claim 23
Dependent Claim
43 words
A coding apparatus as set forth in Claim 14, wherein said block formatting means divides said digital image signal into two-dimensional blocks per every field or every frame, and said orthogonal transforming means performs orthogonal transform per every unit of the two-dimensional block.
Claim 24
Dependent Claim
56 words
A coding apparatus as set forth in Claim 14, wherein said block formatting means divides said digital image signal into three-dimensional blocks in horizontal and vertical directions in each field or frame and in time direction in successive fields or frames, and said orthogonal transforming means performs orthogonal transform per every unit of the three-dimensional block.
Claim 25
Dependent Claim
66 words
A coding apparatus as set forth in Claim 14, further comprising: means for performing variable length coding on the coefficients on which weighting is performed; memory means for storing the variable-length-coded coefficients; and controlling means for detecting the storing amount of said memory means and controlling decision of the weighting factor in said deciding means so as to keep said storing amount within a predetermined volume.
Claim 26
Dependent Claim
18 words
A coding apparatus as set forth in Claim 14, wherein said orthogonal transform is DCT (Discrete Cosine Transform).
Claim 27
Dependent Claim
108 words
A coding apparatus for reducing a digital image signal, comprising: block formatting means for dividing said digital image signal into blocks of plurality of picture elements; orthogonal transforming means for performing orthogonal transform on the formatted image signal; quantizing means for quantizing coefficients obtained through the orthogonal transform with a quantization table; means for dividing each block of the image signal outputted from said block formatting means into a plurality of sub-blocks and obtaining the maximum and minimum values of the image signal level of picture elements in said each sub-block; and deciding means for deciding the quantization table on the basis of said maximum and minimum values.
Claim 28
Dependent Claim
43 words
A coding apparatus as set forth in Claim 27, wherein said block formatting means divides said digital image signal into two-dimensional blocks per every field or every frame, and said orthogonal transforming means performs orthogonal transform per every unit of the two-dimensional block.
Claim 29
Dependent Claim
56 words
A coding apparatus as set forth in Claim 27, wherein said block formatting means divides said digital image signal into three-dimensional blocks in horizontal and vertical directions in each field or frame and in time direction in successive fields or frames, and said orthogonal transforming means performs orthogonal transform per every unit of the three-dimensional block.
Claim 30
Dependent Claim
62 words
A coding apparatus as set forth in Claim 27, further comprising: means for performing variable length coding on the quantized coefficients; memory means for storing the variable-length-coded coefficients; and controlling means for detecting the storing amount of said memory means and controlling decision of the quantization table in said deciding means so as to keep said storing amount within a predetermined volume.
Claim 31
Dependent Claim
18 words
A coding apparatus as set forth in Claim 27, wherein said orthogonal transform is DCT (Discrete Cosine Transform).
Claim 32
Dependent Claim
106 words
A coding apparatus for reducing a digital image signal, comprising: block formatting means for dividing said digital image signal into blocks of plurality of picture elements; orthogonal transforming means for performing orthogonal transform on the formatted image signal; weighting means for performing weighting on coefficients obtained through the orthogonal transform with a weighting factor; means for dividing each block of the image signal outputted from said block formatting means into a plurality of sub-blocks and obtaining the maximum and minimum values of the image signal in said each sub-block; and deciding means for deciding the weighting factor on the basis of said maximum and minimum values.
Claim 33
Dependent Claim
43 words
A coding apparatus as set forth in Claim 32, wherein said block formatting means divides said digital image signal into two-dimensional blocks per every field or every frame, and said orthogonal transforming means performs orthogonal transform per every unit of the two-dimensional block.
Claim 34
Dependent Claim
56 words
A coding apparatus as set forth in Claim 32, wherein said block formatting means divides said digital image signal into three-dimensional blocks in horizontal and vertical directions in each field or frame and in time direction in successive fields or frames, and said orthogonal transforming means performs orthogonal transform per every unit of the three-dimensional block.
Claim 35
Dependent Claim
66 words
A coding apparatus as set forth in Claim 32, further comprising: means for performing variable length coding on the coefficients on which weighting is performed; memory means for storing the variable-length-coded coefficients; and controlling means for detecting the storing amount of said memory means and controlling decision of the weighting factor in said deciding means so as to keep said storing amount within a predetermined volume.
Claim 36
Dependent Claim
18 words
A coding apparatus as set forth in Claim 32, wherein said orthogonal transform is DCT (Discrete Cosine Transform).
Claim 37
Dependent Claim
81 words
A coding apparatus for reducing a digital image signal, comprising: block formatting means for dividing said digital image signal into blocks of plurality of picture elements; orthogonal transforming means for performing orthogonal transform on each formatted block; weighting means, provided with a smaller number of adders than the number of picture elements in said each block, for performing weighting on coefficients obtained through the orthogonal transform; and means for performing variable length coding on said coefficients on which weighting is performed.
Claim 38
Dependent Claim
30 words
A coding apparatus as set forth in Claim 37, wherein the number of said adders is not larger than 1/4 of the number of picture elements in said each block.
Claim 39
Dependent Claim
43 words
A coding apparatus as set forth in Claim 37, wherein said block formatting means divides said digital image signal into two-dimensional blocks per every field or every frame, and said orthogonal transforming means performs orthogonal transform per every unit of the two-dimensional block.
Claim 40
Dependent Claim
56 words
A coding apparatus as set forth in Claim 37, wherein said block formatting means divides said digital image signal into three-dimensional blocks in horizontal and vertical directions in each field or frame and in time direction in successive fields or frames, and said orthogonal transforming means performs orthogonal transform per every unit of the three-dimensional block.
Claim 41
Dependent Claim
18 words
A coding apparatus as set forth in Claim 37, wherein said orthogonal transform is DCT (Discrete Cosine Transform).
Claim 42
Dependent Claim
63 words
A coding apparatus as set forth in Claim 41, wherein said weighting means is provided with means for obtaining a criterion value in correspondence to a sequency degree of a coefficient obtained through the DCT in horizontal direction in a block and a sequency degree thereof in vertical direction, and means for deciding a weighting factor on the basis of said criterion value.
Claim 43
Dependent Claim
50 words
A coding apparatus as set forth in Claim 42, wherein said criterion value is the maximum value of said sequency degree in horizontal direction and sequency degree in vertical direction, so arranged that the same weighting is performed on the coefficients having the same maximum value by the same adder.
Claim 44
Dependent Claim
48 words
A coding apparatus as set forth in Claim 42, wherein said criterion value is the sum of said sequency degree in horizontal direction and sequency degree in vertical direction, so arranged that the same weighting is performed on the coefficients having the same sum by the same adder.
References Cited (Backward Citations)
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