| Autor: |
Witten, Ian H., Neal, Radford M., Cleary, John G., Sibley, Edgar H. |
| Předmět: |
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| Zdroj: |
Communications of the ACM; Jun87, Vol. 30 Issue 6, p520-540, 21p, 12 Diagrams, 4 Charts |
| Abstrakt: |
This article presents information on the use of arithmetic coding for data compression. The article briefly reviews basic concepts of data compression and introduces the model-based approach that underlies most modern techniques. To many, data compression conjures up an assortment of ad hoc techniques such as conversion of spaces in text to tabs, creation of special codes for common words, or run-length coding of picture data. This contrasts with the more modern model-based paradigm for coding, where, from an input string of symbols and a model, an encoded string is produced that is usually a compressed version of the input. The decoder, which must have access to the same model, regenerates the exact input string from the encoded string. The model is a way of calculating in any given context, the distribution of probabilities for the next input symbol. It must be possible for the decoder to produce exactly the same probability distribution in the same context. Compression is achieved by transmitting the more probable symbols in fewer bits than the less probable ones. |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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