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US5038390A
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Method of transform data compression using save-maps
Assignee: Toshiba Corp
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Filing: 1990-06-05
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Granted: 1991-08-06
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Expires: 2010-06-05
Abstract
Abstract A method for compressing the data required to represent an image using a set of save-maps, with each save-map being identified by an index and each save-map identifying a subset of transform coefficients. The method begins by spatially partitioning the image into a plurality of blocks, includes the generation of transform coefficients representative of the data spatially located in each block; the generation of an index for each block as a function of the transform coefficients for that block; and selecting one of the save-maps as a function of the index. By employing the index and the value of the magnitude components of the subset of transform coefficients identified by the selected save-map for each block, compressed data may be obtained representative of that portion of the image spatially contained in each of the corresponding blocks. Thus, each save-map permits retrieving the original image in accordance with the save-map and data representative of the magnitude components of the subsets of transform coefficients identified by the save-maps.
Inventors
- 👤 Vellore C. Ravi Chandran
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 15:38
CPC Classifications
H; H04; H04N; H04N19/00; H04N19/10; H04N19/134; H04N19/154; H04N19/102; H04N19/124; H04N19/132; H04N19/60
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
191 words
A method for compressing the data required to represent an original image by using a predefined set of save-maps, with each save-map being identified by an index and each save-map identifying a subset of transform coefficients, comprising the steps of: spatially partitioning said image into a plurality of blocks; generating, for each block of at least a subset of said plurality of blocks, a set of transform coefficients representative of the data spatially located in that block, with each of said transform coefficients having a magnitude component and a frequency component; partitioning each block of transform coefficients into a plurality of zones, the dimensions of each said zone being a function of the different visual components of the image; generating an index independently for each said block as a function of the energy level in more than one zone of the block; selecting one of said save-maps as a function of said index; and employing said index and the magnitude components of the subset of transform coefficients for each said block identified by said selected save-map for that block to represent that portion of said image spatially contained in that block.
Claim 2
Independent Claim
191 words
A method for compressing the data required to represent an original image by using a predefined set of save-maps, with each save-map being identified by an index and each save-map identifying a subset of transform coefficients, comprising the steps of: spatially partitioning said image into a plurality of blocks; generating, for each block of at least a subset of said plurality of blocks, a set of transform coefficients representative of the data spatially located in that block, with each of said transform coefficients having a magnitude component and a frequency component; partitioning each block of transform coefficients into a plurality of zones, the dimensions of each said zone being a function of the different visual components of the image; generating an index independently for each said block as a function of the energy level in more than one zone of the block; selecting one of said save-maps as a function of said index; and employing said index and the magnitude components of the subset of transform coefficients for each said block identified by said selected save-map for that block to represent that portion of said image spatially contained in that block.
Claim 3
Dependent Claim
140 words
The method of claim 1 wherein the step of generating an index for each said block comprises the steps of: organizing the set of transform coefficients for that block into a matrix based on said frequency components of said transform coefficients; partitioning at least a portion of said matrix into a plurality of zones; summing the absolute values of the magnitude components of the transform coefficients in each zone to obtain a plurality of zone sums; summing the absolute values of the magnitude components of all the transform coefficients to obtain a total sum; dividing each zone sum by said total sum to obtain a normalized zonal activity level for each zone; and comparing said total sum and said normalized zonal activity levels with corresponding predefined empirical values to generate a code which constitutes the index for each said block.
Claim 4
Dependent Claim
78 words
The method of claim 2 wherein the substep of comparing comprises: comparing said total sum for each said block with a series of thresholds to generate a block code for the total sum of that block; comparing the normalized zonal activity level of each zone in that block with a threshold to generate a zone code for each zone sum; and combining said block code and the plurality of zone codes to obtain the index for that block.
Claim 5
Dependent Claim
203 words
The method of claim 1 further comprising the step of generating said set of save-maps by: spatially partitioning at least one sample image similar in character to said original image into a plurality of blocks; generating a set of transform coefficients for each block of at least a subset of said plurality of said blocks, said transform coefficients for each block having a magnitude component and a frequency component, and each said set of transform coefficients being representative of the data located in the corresponding block; partitioning each block of transform coefficients into a plurality of zones, the dimensions of each said zone being a function of the different visual components of the image; generating an index for each said block as a function of the energy level in more than one zone of the block, said index being capable of being computed independently for each said block; selecting from each set of transform coefficients for each block which have the same index, a predefined subset of coefficients to represent that portion of said sample image spatially contained in the corresponding blocks; and generating for each index one save-map as a function of said subsets of transform coefficients corresponding to each said index.
Claim 6
Dependent Claim
26 words
The method of claim 1 further comprising the step of repeating said steps of generating, selecting and employing for each of said plurality of said blocks.
Claim 7
Dependent Claim
34 words
The method of claim 5 further comprising the step of reconstructing said original image in response to said index and said magnitude components of said subset of transform coefficients for each of said blocks.
Claim 8
Independent Claim
280 words
A method for compressing the data required to represent an original image by using a set of save-maps, with each save-map being identified by an index and each save-map identifying a subset of transform coefficients, comprising the steps of: spatially partitioning said image into a plurality of blocks; generating, for each block of at least a subset of said plurality of blocks, a set of transform coefficients representative of the data spatially located in that block, with each of said transform coefficients having a magnitude component and a frequency component; generating an index for each said block as a function of said transform coefficients for that block, comprising the steps of: organizing the set of transform coefficients for that block into a matrix based on said frequency components of said transform coefficients; partitioning at least a portion of said matrix into a plurality of zones; summing the absolute values of the magnitude components of the transform coefficients in each zone to obtain a plurality of zone sums; summing the absolute values of the magnitude components of all the transform coefficients to obtain a total sum; dividing each zone sum by said total sum to obtain a normalized zonal activity level for each zone; and comparing said total sum and said normalized zonal activity level with corresponding predefined empirical values to generate a code which constitutes the index for each said block; selecting one of said save-maps as a function of said index; and employing said index and the magnitude components of the subset of transform coefficients for each said block identified by said selected save-map for that block to represent that portion of said image spatially contained in that block.
Claim 9
Independent Claim
280 words
A method for compressing the data required to represent an original image by using a set of save-maps, with each save-map being identified by an index and each save-map identifying a subset of transform coefficients, comprising the steps of: spatially partitioning said image into a plurality of blocks; generating, for each block of at least a subset of said plurality of blocks, a set of transform coefficients representative of the data spatially located in that block, with each of said transform coefficients having a magnitude component and a frequency component; generating an index for each said block as a function of said transform coefficients for that block, comprising the steps of: organizing the set of transform coefficients for that block into a matrix based on said frequency components of said transform coefficients; partitioning at least a portion of said matrix into a plurality of zones; summing the absolute values of the magnitude components of the transform coefficients in each zone to obtain a plurality of zone sums; summing the absolute values of the magnitude components of all the transform coefficients to obtain a total sum; dividing each zone sum by said total sum to obtain a normalized zonal activity level for each zone; and comparing said total sum and said normalized zonal activity level with corresponding predefined empirical values to generate a code which constitutes the index for each said block; selecting one of said save-maps as a function of said index; and employing said index and the magnitude components of the subset of transform coefficients for each said block identified by said selected save-map for that block to represent that portion of said image spatially contained in that block.
Claim 10
Dependent Claim
78 words
The method of claim 7 wherein the substep of comparing comprises: comparing said total sum for each said block with a series of thresholds to generate a block code for the total sum of that block; comparing the normalized zonal activity level of each zone in that block with a threshold to generate a zone code for each zone sum; and combining said block code and the plurality of zone codes to obtain the index for that block.
References Cited (Backward Citations)
US4581638A
Cited
US4553171A
Cited
USPTO Annuity & Maintenance Windows
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| 3.5 Years (Year 4) | 1994-08-05 | 1995-02-04 | 1995-08-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-08-05 | 1999-02-04 | 1999-08-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-08-05 | 2003-02-04 | 2003-08-06 | $7700.00 | Window Closed / Lapsed |