comp.lang.idl-pvwave archive: archive » Fast way to collapse data cube with median

Home » Public Forums » archive » Fast way to collapse data cube with median

Show: Today's Messages :: Show Polls :: Message Navigator
E-mail to friend

Re: Fast way to collapse data cube with median [message #85136 is a reply to message #85133]

Tue, 09 July 2013 09:28

Michael Galloy
Messages: 1114
Registered: April 2006

Senior Member

On 7/9/13 10:08 AM, Stefan wrote:
> Hey
>
> I am doing a lot of image processing and very often I have a data
> cube like with the x/y axes corresponding to image coordinates and
> the z component corresponding to the individual images.
>
> I simply want to calculate the median at each pixel stack and so far
> I always loop through all pixels and determine the median for each
> stack. This, of course, can be quite slow for large images since it
> involves two loops and I was wondering if someone here might have a
> fancy idea of how to collapse such a cube faster.
>
> thank a lot :)
>

Yes, use the DIMENSION keyword to median (dimensions start at 1):

IDL> arr = findgen(2, 3, 4)
IDL> m = median(arr, dimension=2)
IDL> help, m
M FLOAT = Array[2, 4]

Mike
--
Michael Galloy
www.michaelgalloy.com
Modern IDL: A Guide to IDL Programming (http://modernidl.idldev.com)
Research Mathematician
Tech-X Corporation

Report message to a moderator

[Message index]

		Fast way to collapse data cube with median By: stefan.meingast on Tue, 09 July 2013 09:08
		Re: Fast way to collapse data cube with median By: David Fanning on Tue, 09 July 2013 09:22
		Re: Fast way to collapse data cube with median By: Michael Galloy on Tue, 09 July 2013 09:28
		Re: Fast way to collapse data cube with median By: stefan.meingast on Tue, 09 July 2013 10:42
		Re: Fast way to collapse data cube with median By: David Fanning on Tue, 09 July 2013 10:44
		Re: Fast way to collapse data cube with median By: stefan.meingast on Tue, 09 July 2013 12:14

Previous Topic:	Peak detection
Next Topic:	CURVEFIT function

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Fri Oct 10 07:21:14 PDT 2025

Total time taken to generate the page: 0.95232 seconds