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Re: make a vector from all pixels in a moving window [message #74526]

Sat, 22 January 2011 16:28

envi35@yahoo.ca
Messages: 48
Registered: March 2005

Member

On Jan 22, 6:59 pm, Robin Wilson <ro...@rtwilson.com> wrote:
> Hi Jenny,
>
> I use the function below to do this for me. It might not be the most
> efficient way of doing it (my IDL code is often lacking in terms of
> efficiency), but it works:
>
> FUNCTION GET_LOCAL_SUBSET, n, x, y, arr
> ; This gets the local n x n window around the given x and y values
> ; It will repeat edge values as needed to provide the correctly sized
> ; return array
> ;
> ; Altered fromhttp://michaelgalloy.com/2006/10/10/local
> ; grid-points.html (Original Author: Michael Galloy)
> ;
> ; Calculate the offsets
> offsets = lindgen(n) - (n - 1) / 2
>
> ; Calculate the offsets from the given x and y values
> xoffsets = reform(rebin(offsets, n, n), n^2)
> yoffsets = reform(rebin(offsets, n^2), n^2)
>
> return, reform(arr[x + xoffsets, y + yoffsets],n,n)
> END
>
> See Michael's blog post (linked in the comments above) for more
> information on how it works.
>
> Hope this helps,
>
> Robin

This is just what I need! Thanks! Robin

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		Re: make a vector from all pixels in a moving window By: envi35@yahoo.ca on Sat, 22 January 2011 16:28
		Re: make a vector from all pixels in a moving window By: Robin Wilson on Sat, 22 January 2011 15:59

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