Patent US4884154A successfully refreshed from Google Patents.
EP0786902A1
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Method and apparatus for changing resolution by direct DCT mapping
Assignee: Panasonic Holdings Corp
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Filing: 1997-01-23
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Granted: —
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Expires: 2017-01-23
Abstract
Abstract An apparatus for transforming the resolution of an image from a first image resolution to a second image resolution using operations in the spatial frequency domain. A first group of transform values which represent the image at the first image resolution are mapped to a second group of transform values which represent the image at the second image resolution in the spatial frequency domain. The apparatus includes stored pre-computed values which are the mapping coefficient values between the first group of transform values and the second group of transform values. The pre-computed values are retrieved from a memory and used to directly map the first group of transform values to the second group of transform values in the spatial frequency domain.
Inventors
- 👤 Hee-Yong Kim
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-10 01:50
CPC Classifications
G; G06; G06T; G06T3/00; G06T3/40; G06T3/4084; H; H04; H04N; H04N7/00; H04N7/01; H04N19/00; H04N19/10; H04N19/102; H04N19/103; H04N19/107; H04N19/112; H04N19/12; H04N19/122; H04N19/132; H04N19/134; H04N19/136; H04N19/137; H04N19/157; H04N19/16; H04N19/169; H04N19/17; H04N19/172; H04N19/176; H04N19/18; H04N19/186; H04N19/40; H04N19/48; H04N19/50; H04N19/59; H04N19/60; H04N19/61; H04N21/00; H04N21/40; H04N21/45; H04N21/462; H04N5/00; H04N5/14
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
157 words
An apparatus for transforming the
resolution of an image from a first resolution to a second
resolution where a first plurality spatial frequency
coefficient (SFC) values correspond to the image at the
first resolution and a second plurality of SFC values
correspond to the image at the second resolution, the
apparatus comprising: memory means for storing a plurality of pre-computed
values where the pre-computed values determine
the change in the resolution of the image from the first
resolution to the second resolution; and converter means for directly converting the
resolution of the image by mapping the first plurality of
SFC values to the second plurality of SFC values in the
spatial frequency domain, the converter means including: (a) means for combining the pre-computed values
with the first plurality of SFC values to
produce processed values; and (b) means for combining ones of the processed
values to produce at least one of the second
plurality of SFC values.
Claim 2
Dependent Claim
69 words
The apparatus according to claim 1, wherein
the converter means further comprises: means for multiplying one of the plurality of
pre-computed values by one of the first plurality of SFC
values; means for multiplying another one of the
plurality of pre-computed values by one of the first
plurality of SFC values; and means for adding the multiplied values together
to produce one of the second plurality of SFC values.
Claim 3
Dependent Claim
89 words
The apparatus according to claim 1, wherein
the converter means comprises: means for multiplying a first one of the
plurality of pre-computed values by a first one of the
first plurality of SFC values to produce a first
intermediate value; means for multiplying a second one of the
plurality of pre-computed values by a second one of the
first plurality of SFC values to produce a second
intermediate value; and means for combining the first and second
intermediate values to produce one of the second plurality
of SFC values.
Claim 4
Dependent Claim
18 words
The apparatus according to claim 1, wherein
the converter means retrieves the pre-computed values from
the memory means.
Claim 5
Dependent Claim
26 words
The apparatus according to claim 1, wherein
the first plurality of SFC values and the second plurality
of SFC values are Discrete Cosine Transform (DCT)
coefficients.
Claim 6
Dependent Claim
84 words
The apparatus according to claim 5, wherein
the first plurality of SFC values are arranged in blocks
of macroblocks and the second plurality of SFC values are
arranged in converted blocks of converted macroblocks, and
one of the plurality of pre-computed values is used to map
a z1-th DCT coefficient value of a j1-th block of an i1-th
macroblock to a z-th SFC value of a j-th converted block
of an i-th converted macroblock, where z1, j1, i1, z, j,
and i are integers.
Claim 7
Dependent Claim
79 words
The apparatus according to claim 5, wherein
the image at the first resolution is represented by an
MPEG Main Profile, High Level signal which contains the
first plurality of SFC values and the image at the second
resolution is represented by an MPEG Main Profile, Main
level signal which contains the second plurality of SFC
values, and the converter means is further for converting
the MPEG Main Profile, High Level signal to the MPEG Main
Profile, Main level signal.
Claim 8
Dependent Claim
79 words
The apparatus according to claim 5, wherein
the image at the first resolution is represented by an
MPEG Main Profile, Main Level signal which contains the
first plurality of SFC values and the image at the second
resolution is represented by an MPEG Main Profile, High
level signal which contains the second plurality of SFC
values, and the converter means is further for converting
the MPEG Main Profile, High Level signal to the MPEG Main
Profile, Main level signal.
Claim 9
Dependent Claim
52 words
The apparatus according to claim 1, wherein
the first plurality of SFC values includes high frequency
SFC values which correspond to high spatial frequency
components in the image, and the apparatus further
comprises filter means for eliminating the high spatial
frequency components of the image by removing the high
frequency SFC values.
Claim 10
Dependent Claim
42 words
The apparatus according to claim 1, wherein
the pre-computed values represent a combination of
conversion coefficients in the spatial frequency domain
for converting the first plurality of SFC values which is
equivalent to an interpolation of corresponding pixels in
the pixel domain.
Claim 11
Dependent Claim
153 words
A decoder for decoding an MPEG encoded
image and changing the resolution of the encoded image,
the decoder comprising: variable length decoding means for receiving and
decoding an input signal containing DCT values, the DCT
values defining a first resolution of the image; inverse quantization means for dequantizing the
DCT values; and memory means for storing a plurality of pre-computed
values where the pre-computed values determine
the change in a resolution of the encoded image from the
first resolution to a second resolution; and converter means for directly converting the
resolution of the encoded image by mapping the DCT
coefficient values to a plurality of converted coefficient
values in the spatial frequency domain, the converter
means including: (a) means for combining the pre-computed values
with the DCT coefficient values to produce
processed values; and (b) means for combining the processed values to
produce at least one of the plurality of
converted coefficient values.
Claim 12
Independent Claim
152 words
A method for transforming the resolution of
an image from a first resolution to a second resolution
where a first plurality spatial frequency coefficient
(SFC) values correspond to the image at the first
resolution and a second plurality of SFC values correspond
to the image at the second resolution, the method
comprising the steps of: (a) storing a plurality of pre-computed values
where the pre-computed values determine the change in the
resolution of the image from the first resolution to the
second resolution; and (b) directly converting the resolution of the
image by mapping the first plurality of SFC values to the
second plurality of SFC values in the spatial frequency
domain, step (b) comprising the steps of: applying the pre-computed values to the first
plurality of SFC values to produce processed
values; and combining ones of the processed values to
produce at least one of the second plurality of
SFC values.
Claim 13
Dependent Claim
85 words
The method according to claim 12, wherein
step (b) comprises the steps of: multiplying a first one of the plurality of pre-computed
values by a first one of the first plurality of
SFC values to produce a first intermediate value; multiplying a second one of the plurality of
pre-computed values by a second one of the first plurality
of SFC values to produce a second intermediate value; and combining the first and second intermediate
values to produce one of the second plurality of SFC
values.
Claim 14
Dependent Claim
25 words
The method according to claim 12, wherein
the first plurality of SFC values and the second plurality
of SFC values are Discrete Cosine Transform coefficients.
Claim 15
Dependent Claim
42 words
The method according to claim 12, wherein
the pre-computed values represent a combination of
conversion coefficients in the spatial frequency domain
for converting the first plurality of SFC values which is
equivalent to an interpolation of corresponding pixels in
the pixel domain.
References Cited (Backward Citations)
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