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   -> Volume 6, Issue 2


Software: C++ wavelet image compression source
 
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Geoff Davis (gdavis@ece.rice.edu)
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PostPosted: Thu Jan 30, 1997 5:16 am    
Subject: Software: C++ wavelet image compression source
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#12 Software: C++ wavelet image compression source

The Wavelet Construction Kit code implements a baseline wavelet
transform-based image coder for grayscale images. The coder is not
the most sophisticated -- it's a simple transform coder -- but each
individual piece of the transform coder has been chosen for high
performance. Symmetric boundary extensions are implemented, bit
allocation is optimized via an integer programming algorithm, and
entropy coding is done with a sophisticated adaptive arithmetic coder.

The code has been designed for experimentation. It's very modular and
should allow for simple replacements of individual components. One
can easily replace the quantizer, the entropy coder, and the wavelet
filters. A number of commonly used filters from the compression
literature have been included, together with references. If you are
doing research on wavelet-based image coding, there's no need to
reinvent the wheel!

The performance of the coder is quite good, even though it does not
make use of zerotrees or side classification information.

Performance data for the 512x512 Lena image as compared to Shapiro's
EZW algorithm:

Compression ratio PSNR (dB) PSNR for EZW (dB)
----------------- --------- -----------------
4.0:1 43.71
8.0:1 39.42 39.55
16.0:1 36.18 36.28
32.0:1 33.17 33.17
64.1:1 30.22 30.23
129.3:1 27.73 27.54

Full source code and details are available at

http://www.cs.dartmouth.edu/~gdavis/wavelet/wavelet.html

Geoff Davis
Math Department
Dartmouth College
gdavis@cs.dartmouth.edu
http://www.cs.dartmouth.edu/~gdavis
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