EP0154860A2
Expired / Lapsed
EP
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Model driven data compression/decompression system for data transfer
Assignee: International Business Machines Corp
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Filing: 1985-02-22
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Granted: —
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Expires: 2005-02-22
Abstract
Abstract Data compression for transfer (storage or communication) by a continuously adaptive probability decision model, closely approaches the compression entropy limit. Sender and receiver perform symmetrical compression/decompression of binary decision n according to probabilities calculated independently from the transfer sequence of 1...n-1 binary decisions. Sender and receiver dynamically adapt the model probabilities, as a cumulative function of previously presented decisions, for optimal compression/decompression. Adaptive models for sender and receiver are symmetrical, to preserve data identity; transfer optimization is the intent. The source model includes a state generator and an adaptive probability generator, which dynamically modify the coding of decisions according to state, probability and bit signals, and adapt for the next decision. The system calculates probability history for all decisions, including the current decision, but uses probability history for decision n-1 (the penultimately current decision) for encoding decision n (the dynamically current decision). The system, separately at source and destination, reconfigures the compression/expansion algorithm, on a penultimately current basis, codes each decision in the data stream optimally, according to its own character in relation to the calculated probability history, and dynamically reconfigures the current decision to the penultimately current transfer optimum.
Inventors
- 👤 Gerald Goertzel
- 👤 Joan La Verne Mitchell
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 23:35
CPC Classifications
H; H03; H03M; H03M7/00; H03M7/30; H03M7/40; H03M7/4006
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
93 words
A model driven data compression/decompression system for data transfer characterized by: (a) model driven adaptive probability compression means comprising coding means for coding data as binary decision n according to the model, the probability for decision n being a model-based probability adapted from binary decisions I...n-1; (b) transfer means connected to said model driven adaptive probability compression means; (c) model driven adaptive probability decompression means comprising decoding means for decoding data as binary decision n according to the model, the probability for decision n being a model-based probability adapted from binary decisions l...n-1.
Claim 2
Dependent Claim
93 words
A model driven data compression/decompression system for data transfer characterized by: (a) model driven adaptive probability compression means comprising coding means for coding data as binary decision n according to the model, the probability for decision n being a model-based probability adapted from binary decisions I...n-1; (b) transfer means connected to said model driven adaptive probability compression means; (c) model driven adaptive probability decompression means comprising decoding means for decoding data as binary decision n according to the model, the probability for decision n being a model-based probability adapted from binary decisions l...n-1.
Claim 3
Dependent Claim
283 words
A model driven compression/decompression system for data transfer characterized by: (a) data input means; (b) model means including a state generator, providing for the current binary decision bit and a state signal, which may be a multi-bit signal; (c) adaptive probability generator means, a part of said model means, responsive to state signal and to bit signal to provide a probability signal modified for history of binary decisions 1...n-1, updated for each decision; (d) coder means connected to said model means responsive to the state signal and the bit signal for each binary decision and to the probability signal provided to generate a compressed data group for transfer; (e) transfer means; (f) decoder means, connected to said transfer means and to destination model means (h) and to destination adaptive probability generator means (i), responsive to compressed data transfer signals and to destination state signals and destination adaptive probability signals to provide decompressed bit signals for binary decision n; (g) output means, for providing at the destination a data stream of decompressed data corresponding to the data stream of binary decisions at said input means, which may be deisgnated n=l, 2...N-1, N and repeating n=l, 2...N-1, N; (h) destination model means including a state generator, providing for the current binary decision, a destination state signal, which may be a multi-bit signal, and responsive to said decoder bit signal to provide output data to said output means; (i) destination adaptive probability generator means, connected to said destination model means and to said decoder means, responsive to said destination bit signal and to said destination state signal to provide output data to said output means. (j) a probability signal modified for history of binary decisions 1...n;
Claim 4
Dependent Claim
283 words
A model driven compression/decompression system for data transfer characterized by: (a) data input means; (b) model means including a state generator, providing for the current binary decision bit and a state signal, which may be a multi-bit signal; (c) adaptive probability generator means, a part of said model means, responsive to state signal and to bit signal to provide a probability signal modified for history of binary decisions 1...n-1, updated for each decision; (d) coder means connected to said model means responsive to the state signal and the bit signal for each binary decision and to the probability signal provided to generate a compressed data group for transfer; (e) transfer means; (f) decoder means, connected to said transfer means and to destination model means (h) and to destination adaptive probability generator means (i), responsive to compressed data transfer signals and to destination state signals and destination adaptive probability signals to provide decompressed bit signals for binary decision n; (g) output means, for providing at the destination a data stream of decompressed data corresponding to the data stream of binary decisions at said input means, which may be deisgnated n=l, 2...N-1, N and repeating n=l, 2...N-1, N; (h) destination model means including a state generator, providing for the current binary decision, a destination state signal, which may be a multi-bit signal, and responsive to said decoder bit signal to provide output data to said output means; (i) destination adaptive probability generator means, connected to said destination model means and to said decoder means, responsive to said destination bit signal and to said destination state signal to provide output data to said output means. (j) a probability signal modified for history of binary decisions 1...n;
Claim 5
Dependent Claim
27 words
A data compression/decompression system according to claim 2, further including delay count means to record binary decisions which have not yet been included in the probability calculation.
Claim 6
Dependent Claim
23 words
A data compression/decompression system according to claim 2, further including binary shift means to accomplish the equivalent of multiplication or division by 2.
Claim 7
Dependent Claim
20 words
A data compression/decompression according to claim 2, further including zero byte insertion means to ensure proper handling of the carry.
Claim 8
Dependent Claim
20 words
A data compression/decompression according to claim 2, further including means to shift the finite precision window in data group units.
Claim 9
Dependent Claim
22 words
A data compression/decompression system according to claim 2, wherein said transfer means is a communication channel for data transfer over a distance.
Claim 10
Dependent Claim
20 words
A data compression/decompression system according to claim 2, wherein said transfer means is a storage for data transfer over time.
References Cited (Backward Citations)
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