From help-request at octave dot org Fri Jan 7 23:46:10 2005 Subject: Efficiently accessing subarrays from an image file... From: Jonathan Greenberg To: Date: Fri, 07 Jan 2005 21:48:21 -0800 I was hoping I could get some hints on the most efficient way to perform "window" analyses on an image: inputs: large multiband image (satellite imagery), binary format analysis: perform some repeated algorithm using a moving window of a fixed size - example: for each location in the matrix, calculate the variance of the 3 x 5 rectangle of matrix elements (e.g. Pixels) surrounding the current location What I'm hoping are some ways to speed this up for use in a MP environment -- what optimizations can help me do this? --j -- Jonathan A. Greenberg Ph.D., Ecology AIM: jgrn307 or jgrn3007 MSN: jgrn307 at hotmail dot com or jgrn3007@hotmail.com ------------------------------------------------------------- Octave is freely available under the terms of the GNU GPL. Octave's home on the web: http://www.octave.org How to fund new projects: http://www.octave.org/funding.html Subscription information: http://www.octave.org/archive.html -------------------------------------------------------------