
ompressionrelated
information

The FAQ and more pointers
Generalpurpose compressors
 The implementation of
arithmetic coding from the 1987 paper by Witten, Neal, and Cleary may be
found via ftp://ftp.cpsc.ucalgary.ca/pub/projects/ar.cod/.
A separate implementation of the same coding scheme can be found in The Data Compression Book by
Nelson and Gailly. The code from Arithmetic coding revisited by
Alistair Moffat, Radford Neal, and Ian H. Witten can be found on Moffat's
page http://www.cs.mu.oz.au/~alistair.
 supports
the Zip and UnZip programs, widely used on many platforms. http://www.cdrom.com/pub/infozip/
contains pointers to source code
and documentation, and information about the authors.
 (GNU
zip) was designed to replace compress. The compression
library uses the same algorithm as Zip and gzip.
 Dr Ross's Compression Crypt
contains Ross Williams' notes and sources for his work on various
compressionrelated topics, including the LZRW family of algorithms.
Graphics compression
Fractal methods
 Yuval Fisher's page http://inls.ucsd.edu/Research/Fisher/Fractals
contains a wealth of information and pointers to fractal methods. His Fractal
Image Compresson contains a nicelydone introduction to the topic.
 The Waterloo Fractal Compression
Project at http://links.uwaterloo.ca
is another large page. Included is a pointer to the ``Waterloo BragZone''
which introduces a test suite and includes test results from various
coders.
 The second edition of The
Data Compression Book includes a chapter on fractal compression (by
Jeanloup Gailly). Online information is available through Nelson's page and http://www.teaser.fr/~jlgailly/.
Wavelets
 The Wavelet Digest at http://www.wavelet.org may be a good
starting point. Colm Mulcahy's December 1996 Mathematics Magazine article
contains an elementary introduction. A number of his papers, along with
Matlab code and images, are available from http://www.spelman.edu/~colm.
 Some images in Information
Theory and Data Compression were generated with Geoff Davis' Wavelet
Image Compression Construction Kit, available through http://www.cs.dartmouth.edu/~gdavis.
Miscellaneous
 The GNU Project started in
1984 to develop a complete free Unixlike operating system. GNU zip (a
generalpurpose compressor) and Octave (a matrix language) are covered
under the GNU General Public License. Information about the Free Software
Foundation and the GNU Project is available through http://www.gnu.ai.mit.edu.
 The League for Programming
Freedom (LPF) is an organization that opposes software patents and
userinterface copyrights. The future of the LPF is uncertain (http://www.lpf.org is not currently
available).
 A searchable database of
patent information is available from the US Patent and Trademark Office
via http://www.uspto.gov.