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Data compression using adaptive transform coding. Appendix 1: Item 1Adaptive low-rate source coders are described in this dissertation. These coders adapt by adjusting the complexity of the coder to match the local coding difficulty of the image. This is accomplished by using a threshold driven maximum distortion criterion to select the specific coder used. The different coders are built using variable blocksized transform techniques, and the threshold criterion selects small transform blocks to code the more difficult regions and larger blocks to code the less complex regions. A theoretical framework is constructed from which the study of these coders can be explored. An algorithm for selecting the optimal bit allocation for the quantization of transform coefficients is developed. The bit allocation algorithm is more fully developed, and can be used to achieve more accurate bit assignments than the algorithms currently used in the literature. Some upper and lower bounds for the bit-allocation distortion-rate function are developed. An obtainable distortion-rate function is developed for a particular scalar quantizer mixing method that can be used to code transform coefficients at any rate.
Document ID
19920009877
Acquisition Source
Legacy CDMS
Document Type
Thesis/Dissertation
Authors
Rost, Martin Christopher
(Nebraska Univ. Lincoln, NE, United States)
Date Acquired
September 6, 2013
Publication Date
October 1, 1988
Subject Category
Computer Programming And Software
Report/Patent Number
NASA-CR-189956
NAS 1.26:189956
Accession Number
92N19119
Funding Number(s)
CONTRACT_GRANT: NAG5-916
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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