Article View: sci.image.processing
Article #119Re: FFT's. Help with Region Segmentation
From: Kris Popat
Date: Thu, 06 Aug 1992 16:50
Date: Thu, 06 Aug 1992 16:50
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In article <ALIEN.92Aug6090438@vulcan.essex.ac.uk>, alien@essex.ac.uk
("Adrian F Clark") writes
> that it can be decomposed into a series of 1-D FFTs. In other words,
> you FFT along all the rows, then FFT down all the columns. (This is
> not, however a very efficient way to do it!) [...]
Actually, row-column decomposition IS a fairly efficient way to
compute a 2-D DFT. Slightly faster methods exist (e.g., vector-radix
FFTs), but the speed-up over row-column decomposition is usually
small, and may not be worth the extra difficulty in programming
(considerable). Row-column decomposition gets you down to the right
order of complexity.
The following is a good introductory reference:
AUTHOR: Lim, Jae S.
TITLE: Two-dimensional signal and image processing /
EDITION: c1990.
IMPRINT: Englewood Cliffs, N.J. : Prentice Hall,
Kris Popat
MIT Rm. E15-355 Cambridge, MA 02139 popat@media-lab.mit.edu
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Newsgroups: sci.image.processing Path: arc1-ca.pugleaf.net!sparky!uunet!stanford.edu!snorkelwacker.mit.edu!news.media.mit.edu!news.media.mit.edu!popat From: popat@image.mit.edu (Kris Popat) Subject: Re: FFT's. Help with Region Segmentation In-Reply-To: alien@essex.ac.uk's message of 6 Aug 92 08:04:38 GMT Message-ID: <POPAT.92Aug6115014@image.mit.edu> Sender: news@news.media.mit.edu (USENET News System) Organization: MIT Advanced Television Research Program References: <1992Aug6.111336.9896@waikato.ac.nz> <ALIEN.92Aug6090438@vulcan.essex.ac.uk> Date: Thu, 6 Aug 1992 16:50:14 GMT Lines: 24