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   -> Volume 5, Issue 2


Web: Steerable Pyramid design data available
 
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Ken Castleman (castleman@psii.persci.com)
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PostPosted: Wed Dec 04, 2002 9:49 am    
Subject: Web: Steerable Pyramid design data available
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Web: Steerable Pyramid design data available

I recently added an example of the steerable pyramid transform [1] to
my Web page. The steerable pyramid decomposition uses directional
derivative bandpass filters that have useful shiftability properties
in both position and orientation. It avoids aliasing when
downsampling, effecting a modestly overcomplete representation. It can
be designed to use any number, k, of directional bandpass filters (k =
1 is omnidirectional, k = 2 is bidirectional, etc.).

You can download 17x17 versions of the convolution kernels required to
implement the steerable pyramid transform for k = 1, 2, 3, and 4;
MathCAD(TM) [2] files that compute and plot these kernels and their
transfer functions, and WiT(TM) [3] igraph files that implement the
decomposition and reconstruction of an image.

The Web page also has examples of the 2-dimensional Haar transform
done on a small matrix in MathCAD and on an image in WiT. You can
download these files as well. The page is at:

http://www.phoenix.net/~castlman/

References

1. E. P. Simoncelli, W. T. Freeman, E. H. Adelson and D. J. Heeger,
"Shiftable Multiscale Transforms," IEEE Trans. IT-38(2)587-607, March, 1992.
2. Mathsoft, Inc., http://www.mathsoft.com.
3. Logical Vision, Ltd, http://web.ucs.ubc.ca/lvision/.

Kenneth R. Castleman, Ph. D. castleman@psii.persci.com
Perceptive Scientific Instruments, Inc. 713-334-3027 (voice)
2525 South Shore Blvd. Suite 100 713-538-2222 (fax)
League City, TX 77573 http://www.phoenix.net/~castlman/
All times are GMT + 1 Hour
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