Re: Interpolation question

[Craig Markwardt <craigmnet(at)cow.physics.wisc.edu>]

rkj@dukebar.crml.uab.edu (R. Kyle Justice) writes:

> I have an image containg some bad values.  I would like
> to replace these points with the average value of their
> neighbors.  Is there an easy way to do this without loops?
> 
> For instance, a 3x3 array as follows:
> 
> 1 1 1
> 1 0 1
> 1 1 1
> 
> would become
> 
> 1 1 1
> 1 1 1
> 1 1 1.
> 
> I can't get the boundary conditions to work correctly when
> I use CONVOL.  It either zeros the edges or does not process 
> them.

How about a hybrid approach?  Use CONVOL for the center of the image,
and then special-case the stripes around the edges.  Or, better yet,
check out the MEDIAN function for sliding median smoothing.

Good luck,
Craig

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Craig B. Markwardt, Ph.D.         EMAIL:    craigmnet@cow.physics.wisc.edu
Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response
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