Data compression using set partitioning in hierarchical trees
First Claim
1. A method for use in encoding and decoding a subband decomposition of a data set, said method comprising the steps of:
- (a) creating a list (LIS) consisting of insignificant sets of points, each set of said LIS being designated by a root node within said subband decomposition and having a corresponding tree structure of points within said subband decomposition, said corresponding tree structure of points being organized only as descendants and offspring of said root node and not including the root node, wherein a first generation of said descendants comprise said offspring;
(b) evaluating said descendants of said root node of each set of said LIS for significance, wherein a significant descendent of said descendants of said root node has a coefficient at least equal to a predetermined threshold;
(c) for each root node of said LIS having at least one significant descendant, evaluating descendants of said offspring of said root node for significance, wherein a significant descendant of said offspring of said root node has a coefficient at least equal to said predetermined threshold; and
(d) if said root node has at least one significant descendant of offspring, then adding additional sets corresponding to each of said offspring of said root node to said LIS as a root node thereof.
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Abstract
A data compression technique includes a subband decomposition of a source image followed by coding of the coefficients of the resultant subband decomposition for storage and/or transmission. During coding, three ordered lists are used comprising a list of significant pixels (LSP), a list of insignificant pixels (LIP) and a list of insignificant sets of pixels (LIS). The pixels in the LIP are tested, and those that are significant at a current quantization level are moved to the LSP. Similarly, sets are sequentially evaluated following the LIS order, and when a set is found to be significant it is removed from the LIS and partitioned into new subsets. The new subsets with more than one element are added back to the end of the LIS, while the single-coordinate sets are added to the end of the LIP or to the end of the LSP, depending whether they are insignificant or significant, respectively.
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Citations
13 Claims
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1. A method for use in encoding and decoding a subband decomposition of a data set, said method comprising the steps of:
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(a) creating a list (LIS) consisting of insignificant sets of points, each set of said LIS being designated by a root node within said subband decomposition and having a corresponding tree structure of points within said subband decomposition, said corresponding tree structure of points being organized only as descendants and offspring of said root node and not including the root node, wherein a first generation of said descendants comprise said offspring; (b) evaluating said descendants of said root node of each set of said LIS for significance, wherein a significant descendent of said descendants of said root node has a coefficient at least equal to a predetermined threshold; (c) for each root node of said LIS having at least one significant descendant, evaluating descendants of said offspring of said root node for significance, wherein a significant descendant of said offspring of said root node has a coefficient at least equal to said predetermined threshold; and (d) if said root node has at least one significant descendant of offspring, then adding additional sets corresponding to each of said offspring of said root node to said LIS as a root node thereof. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A computer program comprising a computer useable medium having computer readable program code therein for use in encoding and decoding a subband decomposition of a data set, said computer readable program code in said computer program comprising:
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first computer readable program code for causing a computer to affect creating a list (LIS) consisting of insignificant sets of points, each set of said LIS being designate by a root node within said subband decomposition and having a corresponding tree structure of points within said subband decomposition, said corresponding tree structure being organized only as descendants and offspring of said root node and not including said root node, wherein a first generally of said descendants comprise said offspring; second computer readable program code for causing a computer to affect evaluating said descendants of said root node of each set of said LIS for significance, wherein a significant descendent of said descendants of said root node has a coefficient at least equal to said predetermined threshold; third computer readable program code for causing a computer to affect for each root node of said LIS having at least one significant descendant, evaluating descendants of said offspring of said root node for significance, wherein a significant descendant of said offspring of said root node has a coefficient at least equal to said predetermined threshold; and fourth computer readable program code for causing a computer to affect adding additional sets corresponding to each of said offspring of said root node to said LIS as a root node thereof when said root node has at least one significant descendant of offspring.
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Specification