Image analysis – Image compression or coding
Reexamination Certificate
1999-06-02
2001-11-27
Couso, Jose L. (Department: 2621)
Image analysis
Image compression or coding
Reexamination Certificate
active
06324304
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a picture coding apparatus and the method, and is suitably applicable to, for example, a picture coding apparatus that divides and codes the predetermined picture data into the plural picture data composed of different resolutions.
BACKGROUND ART
Heretofore, as this sort of picture coding apparatus, there is such a device that hierarchically codes an input picture data using a hierarchical coding scheme such as the pyramidal coding scheme (Japanese Patent Publication No. 142836/1993). In this picture coding apparatus, the high resolution input picture data is treated as the first hierarchy data, and the second hierarchy data which has a lower resolution than the first hierarchy data, the third hierarchy data which has a lower resolution than the second hierarchy data, . . . are formed sequentially and recursively, and these plural hierarchy data are transmitted through a transmission line which is composed of one communication channel or a recording/reproducing path.
A picture decoding device which decodes the plural hierarchy data is able to decode all of the plural hierarchy data, and also is able to select and decode the desired one out of the hierarchy data, based on the resolution of a corresponding television monitor and the like. By decoding only the desired hierarchy data out of thus hierarchized plural hierarchy data, the desired picture data can be obtained, with the irreducible minimum of transmitting data quantity.
As shown in
FIG. 1
, the picture coding apparatus which realizes this hierarchical coding such as a four hierarchy coding has decimating filters
2
,
3
,
4
and interpolating filters
5
,
6
,
7
both for three stages, and progressively forms the compacted picture data D
2
, D
3
, D
4
of which the resolutions are low by the decimating filters
2
,
3
,
4
of each stage with respect to the input picture data D
1
, and returns the resolutions of the compacted picture data D
2
, D
3
, D
4
to the former resolution prior to the compaction by the use of the interpolating filters
5
,
6
,
7
.
The output D
2
to D
4
of respective decimating filters
2
to
4
and the output D
5
to D
7
of the respective interpolating filters
5
to
7
are inputted into the difference circuit
8
,
9
,
10
respectively, hereby the difference data D
8
, D
9
, D
10
is generated. As a result, in the picture coding apparatus
1
, the data quantity of the hierarchical data is reduced and the signal power is reduced. The sizes of the difference data D
8
, D
9
, D
10
and the compacted picture data D
4
are 1, ¼, {fraction (1/16)}, and {fraction (1/64)} times the size of the input picture data D
1
in area, respectively.
The difference data D
8
to D
10
which are obtained from the respective difference circuit
8
to
10
and the compacted picture data D
4
which is obtained from the decimating filter
4
are compressed by respective coders
11
,
12
,
13
,
14
. As a result, the first, the second, the third, and the fourth hierarchy data D
11
, D
12
, D
13
, and D
14
which have different resolutions are sent out, in the stated order, from the respective coders
11
,
12
,
13
,
14
to the transmission line.
The first to the fourth hierarchy data D
11
to D
14
which are transmitted in this manner are decoded by a picture decoding apparatus shown in FIG.
2
. The first to the fourth hierarchy data D
11
to D
14
are decoded by decoders
21
,
22
,
23
,
24
respectively. As a result, the fourth hierarchy data D
24
is outputted from the decoder
24
first.
At the adding circuit
29
, the output of the decoder
23
is added to the interpolated data of the fourth hierarchy data D
24
which is obtained from the interpolating filter
26
, hereby the third hierarchy data D
23
is restored. Similarly, at the adding circuit
30
, the output of the decoder
22
is added to the interpolated data of the third hierarchy data D
23
which is obtained from the interpolating filter
27
, hereby the second hierarchy data D
22
is restored. Furthermore, at the adding circuit
31
, the output of the decoder
21
is added to the interpolated data of the second hierarchy data D
22
which is obtained from the interpolating filter
28
, hereby the first hierarchy data D
21
is restored.
In the picture coding device which realizes such a hierarchical coding method, the input picture data is divided into the plural hierarchy data and coded, therefore the data quantity is inevitably increased by the amount of the hierarchy component. Consequently, there is a problem that the compression efficiency is lowered for the amount of the increasing, in comparison with a high efficiency coding method which does not utilize the hierarchical coding. Besides, there is a problem that in the case where the improvement of the compression efficiency is aimed, the deterioration of picture quality is induced, due to the quantizer which is applied between each hierarchy data.
DISCLOSURE OF INVENTION
Considering the above points, the present invention provides a picture coding method and a picture coding apparatus which is able to improve the compression efficiency and is also able to reduce the deterioration of picture quality when hierarchically coding the picture data.
To solve the above problems, in the present invention, a picture coding apparatus for coding inputted picture signal, to recursively generate plural hierarchy data each having a different resolution, comprises: determining and dividing means for determining the way of adaptive division of block which corresponds to the characteristic of the picture data; and transmitting means for transmitting the hierarchically coded data which is obtained from the determining and dividing means. Therefore, the picture data can be divided adaptively into blocks.
Further, in the present invention, a picture coding apparatus for coding inputted picture signal, to sequentially and recursively generate plural hierarchy data each having a different resolution, comprises: determination controlling means for detecting a block activity value of a predetermined block of each hierarchy data excepting the uppermost hierarchy data having the lowest resolution, for generating the division determination flag for determining the way of division of a block on the basis of the block activity value, and when the determined result showing that the block activity value is smaller than the predetermined threshold value is obtained, for generating the division stop flag for stopping the division of the plurality of lower blocks which correspond to the block, and then generating the control signal for stopping the determination of the block activity value of the plurality of lower blocks and the transmission of hierarchy data of the plurality of lower blocks; and transmitting means for transmitting the determination flag of each block along with each coded hierarchy data. Therefore, the decision flag is transmitted along with the picture data which has been divided into blocks.
Further, in the present invention, a picture coding apparatus for coding inputted picture signal, to sequentially and recursively generate plural hierarchy data each having a different resolution, comprises: determination controlling means for detecting the block activity value of a predetermined block of each hierarchy data excepting the uppermost hierarchy data having the lowest resolution, for generating the division determination flag for determining the division of a block based on the block activity value, and when the determined result showing that the block activity value is smaller than the predetermined threshold value is obtained, for temporarily generating the division stop flag for stopping the division of a plurality of lower blocks which correspond to the block, and when the determined result showing that the block activity value of at least one of the plurality of lower blocks is greater than or equal to the predetermined threshold value is obtained, for changing the division stop flag to the division continue flag for continuing the div
Fujimori Yasuhiro
Kawaguchi Kunio
Kondo Tetsujiro
Couso Jose L.
Frommer William S.
Frommer & Lawrence & Haug LLP
Smid Dennis M.
Sony Corporation
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