Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site mplvax.UUCP Path: utzoo!linus!philabs!prls!amdimage!amdcad!decwrl!decvax!ittatc!dcdwest!sdcsvax!sdcc3!mplvax!cdl From: cdl@mplvax.UUCP (Carl Lowenstein) Newsgroups: net.graphics Subject: Re: FFT of image in sections ? Message-ID: <208@mplvax.UUCP> Date: Thu, 8-Aug-85 11:55:31 EDT Article-I.D.: mplvax.208 Posted: Thu Aug 8 11:55:31 1985 Date-Received: Mon, 12-Aug-85 06:38:14 EDT References: <360@ur-laser.uucp> Reply-To: cdl@mplvax.UUCP (Carl Lowenstein) Organization: Marine Physical Laborator of SIO at UCSD Lines: 14 In article <360@ur-laser.uucp> nitin@ur-laser.uucp (Nitin Sampat) writes: >We know that processing small images takes less time. Well, how does >one go about breaking up a large image and process it in sections, >and then most importantly, how does one put all these sections back >to get the FFT of the original image ? Just a little philosophical fuel on the fire: The whole idea behind the FFT (what makes it *F*ast) is that breaking a large dataset into sections, processing the sections, and then recombining them is faster than processing the whole thing all at once. (recursively, down to sections of size 2 or 4). -- carl lowenstein marine physical lab u.c. san diego {ihnp4|decvax|akgua|dcdwest|ucbvax} !sdcsvax!mplvax!cdl