Orthogonal transform apparatus

Details Orthogonal transform apparatus Orthogonal transform apparatus

1998-11-09

2001-05-22

Mai, Tan V. (Department: 2121)

Electrical computers: arithmetic processing and calculating

Electrical digital calculating computer

Particular function performed

C708S402000, C708S405000

Reexamination Certificate

active

06237012

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an orthogonal transform apparatus and method capable of enlarging and shrinking an image and orthogonally transforming input data in orthogonal transform of an image such as dynamic-image data.
2. Related Art of the Invention
The method disclosed in the official gazette of Japanese Patent Laid-Open No. 143723/1993 has been known so far as a method for shrinking a dynamic image. Moreover, the method disclosed in the official gazette of Japanese Patent Application No. 200362/1992 has been known so far as a method for enlarging a dynamic image. The enlarging and shrinking methods disclosed in these official gazettes purpose the input of an 8-row 8-column discrete cosine transform (DCT) coefficient.
FIG. 9
shows a conventional inverse-DCT apparatus for shrinking an image size. In
FIG. 9
, a changeover switch
95
has input terminals a, b, and c. The input terminal. is connected to the output of an 8×8 inverse-DCT circuit
92
, the input terminal b is connected to that of 4×4 inverse-DCT circuit
93
, and the input terminal c is connected to that of a 2×2 inverse-DCT circuit
94
. Any one of these input terminals is selected and set in accordance with a control signal supplied from a control circuit
97
to output pixel data
98
. The 8×8 inverse-DCT circuit
92
is a circuit for inverse-DCT-processing an 8×8 DCT coefficient
91
. The 4×4 inverse-DCT circuit
93
is a circuit for inverse-DCT-processing a 4×4 DCT coefficient to reduce the length and width of an image size to ½ respectively and the 2×2 inverse-DCT circuit
94
is a circuit for inverse-DCT-processing a 2×2 DCT coefficient and reducing an image size to ¼. In this case, when an input is the 8×8 DCT coefficient
91
, the 8×8 DCT coefficient
91
is directly input to the 8×8 inverse-DCT circuit
92
and inverse-DCT-processed to become 8×8 pixel data. To shrink an image to ½, the 4×4 DCT coefficient of the low-band component of the 8×8 DCT coefficient
91
is input to the 4×4 inverse-DCT circuit
93
and inverse-DCT-processed to become 4×4 pixel data and a ½-size image. To shrink an image to ¼, the 2×2 DCT coefficient of the low-band component of the 8×8 DCT coefficient
91
is input to the 2×2 inverse-DCT circuit
94
and inverse-DCT-processed to become 2×2 pixel data and a ¼-size image.
FIG. 10
shows a conventional inverse-DCT apparatus for enlarging an image size. In
FIG. 10
, enlargement-block generation means
102
generates a new DCT coefficient of N
1
×N
2
size (N
1
and N
2
are integers larger than 8) by using the 8×8 DCT coefficient
101
as a low-band component and a high-band component as 0. By inverse-DCT-processing the new N
1
×N
2
DCT coefficient by inverse-DCT means
103
, N
1
×N
2
pixel data
104
is generated and an image enlarged by N⅛ times in the longitudinal direction and by N{fraction (2/8)} times in the cross direction.
To realize the orthogonal transform apparatus capable of enlarging and shrinking an image with hardware, a inverse-DCT circuit for enlargement and a inverse-DCT circuit for shrinkion are necessary and moreover, an n-order inverse-DCT circuit (n is a natural number) is necessary. Thereby, because n inverse-DCT circuits are necessary, it is necessary to newly design an n-order inverse-DCT circuit for each degree. Moreover, a problem occurs that a circuit size increases because n inverse-DCT circuits are combined.
SUMMARY OF THE INVENTION
The present invention is made to solve the conventional problem that a circuit size increases to realize an orthogonal transform apparatus capable of enlarging and shrinking an image with hardware and its object is to provide an orthogonal transform apparatus whose circuit size is small.
It is another object of the present invention to provide an orthogonal transform apparatus capable of enlarging and shrinking an image by using an orthogonal transform apparatus used at present without newly requiring an orthogonal transform apparatus having a different degree.
An orthogonal transform apparatus of the present invention comprises;
orthogonal transform means for performing n-dimensional s-order (n and s are natural numbers) orthogonal transform, modified-information control means for performing control in accordance with modified information for outputting n-dimensional m-order data as n-dimensional p-order data (m and p are natural numbers), and rearrangement means for performing the following in accordance with the control by said modified-information control means:
(1) m-p data values from the high-order side out of m-order input data values are set to 0 when m is equal to s and m is larger than p, p-m data values are added to the high-order side among m-order input data values to rearrange the data values when m is smaller than p, or data values are left as they are when m is equal to p;
(2) the data values in said Item (
1
) are rearranged after discarding m-s data values from the high-order side of said m-order input data values before rearranging the data values in said Item (
1
) when m is larger than s; and
(3) the data values in said Item (
1
) are rearranged after adding s-m 0 data values to the high-order side of said m-order input data values before rearranging the data values in said Item (
1
) when m is smaller than s; wherein
said orthogonal transform means performs orthogonal transform for the n-dimensional s-order data values rearranged by said rearrangement means.
An orthogonal transform apparatus of the present invention comprises orthogonal transform means for performing the orthogonal transform of n-dimensional s-order (n and s are natural numbers), modified-information control means for performing control in accordance with the modified information for outputting n-dimensional m-order data as n-dimensional p-order data (m and p are natural numbers), and rearrangement means for performing the following in accordance with the control by said modified-information control means:
(1) m-p data values from the high-order side out of m-order input data values are set to 0 when m is equal to s and m is larger than p, p-m data values are added to the high-order side among m-order input data values to rearrange the data values when m is smaller than p, or data values are left as they are when m is equal to p;
(2) the data values in said Item (
1
) are rearranged after discarding m-s data values from the high-order side of said m-order input data values before rearranging the data values in said Item (
1
) when m is larger than s; and
(3) the data values in said Item (
1
) are rearranged after adding s-m 0 data values to the high-order side of said m-order input data values before rearranging the data values in said Item (
1
) when m is smaller than s; wherein
said orthogonal transform means performs orthogonal transform for the n-dimensional s-order data values rearranged by said rearrangement means and moreover, performs level adjustment for the data values.
An orthogonal transform apparatus of the present invention for two-dimensionally orthogonally transforming two-dimensional data of m
1
rows and m
2
columns into tow-dimensional data of pl rows and p
2
columns, comprises first orthogonal transform means for performing one-dimensional s1-order orthogonal transform, second orthogonal transform means for performing one-dimensional s
2
-order orthogonal transform, modified-information control means for performing control in accordance with modified information, and first rearrangement means for performing the following in accordance with the control by said modified-information control means:
(1) m
1
−p
1
data values from the high-order side out of m
1
-order input data values are set to 0 when m
1
is equal to s
1
and m
1
is larger than p
1
, p
1
−m
1
data values are added to the high-order side among m
1
-order input data values to r

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