LZW


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LZW

(Lempel-Ziv-Welch) A data compression method that stems from techniques introduced by Jacob Ziv and Abraham Lempel. LZW has been used in many hardware and software products, including V.42bis modems, GIF, TIF and PDF files and PostScript Level 2. The LZ77 method creates pointers back to repeating data, while LZ78 creates a dictionary of repeating phrases with pointers to those phrases.

The Welch in Lempel-Ziv-Welch is for Terry Welch, the Unisys researcher who created an enhanced version of these methods that was patented by Unisys. Unisys collected royalties from thousands of software publishers whose applications used this algorithm until the patents expired in 2004. This was the most widely licensed data compression patent in history. See PNG.
References in periodicals archive ?
Here, LZW has the smallest compression ratio; this maybe because the repeatability of data is not good enough and extra data volume is occupied to construct coding dictionary.
TIFF LZW,###This method is a technique that can get better the compression relation for 24-bit
1 Diccionario de Ejemplo del Algoritmo LZW Diccionario Sa Indice Entr 1 _ 2 a 3 b 4 o 5 w 5 6 wa 2 7 ab 3 8 bb 3 9 ba 2 10 a_ 1 11 _w 6 12 wab 8 13 bba 10 14 a_w 12 15 wab 9 16 ba_ 11 17 _wa 7 18 abb 16 19 ba_ 5 20 wo 4 21 oo 4 22 o_ 11 23 _wo 21 24 oo_ 23 25 _wo 4 Tabla No.
Shift- and approach to pattern matching in LZW compressed text.
Run-length and LZW encoding result in no loss of data; DCT does in fact result in some data loss due to round-off errors, but the overall effect on the quality of the resulting image is inconsequential.
Sperry received a patent for LZW in 1985 and the following year merged with Burroughs to form Unisys.
Whenever you have the option of compressing in LZW over JPEG, do it," said Childress.
This is content that doesn't present redundancies for a dedupe algorithm, and generic compression algorithms such as LZW really add no benefit," said Davis.
TIFF CMYK 300 DPI scanning LZW some 120,000 cards held by the geographical establishment interarmes.
5) In principle, SDE is a clever application of the well-known LZW compression algorithm [71] on expressions.
DH-LZW: lossless data hiding method in LZW compression, PCM2004, LNCS vol.