Dictionary Techniques
Abstract
In this chapter, we present techniques that incorporate the structure in the data in order to increase the amount of compression. These techniques—both static and adaptive (or dynamic)—build a list of commonly occurring patterns and encode these patterns by transmitting their index in the list. They are most useful with sources that generate a relatively small number of patterns quite frequently, such as text sources and computer commands. We discuss applications to text compression, modem communications, and image compression.
Keywords
Digram coding; Lempel–Ziv complexity; LZ77; LZ78; LZSS; LZW; GIF; PNG
5.1 Overview
And now for something somewhat different. In the previous two chapters, we ...
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