comp.lang.idl-pvwave archive: archive » Re: 2D interpolation with sparse data

Home » Public Forums » archive » Re: 2D interpolation with sparse data

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

Re: 2D interpolation with sparse data [message #54099 is a reply to message #54095]

Tue, 22 May 2007 10:06

ben.bighair
Messages: 221
Registered: April 2007

Senior Member

On May 22, 10:38 am, Ken G <kagoldb...@gmail.com> wrote:
> Here's an interesting interpolation problem.
>
> Suppose I have a coarsely sampled 2D dataset--an image. There are
> several ways to fill-in the missing data, including TRIGRID and
> TRI_SURF, etc. What I find though, is that these methods can introduce
> severe artifacts due to the nature of the triangulation.
>
> This example figure here shows the problem clearly:
> http://goldberg.lbl.gov/newsgroup/interpolation_problem.jpg[28k]
>
> My original image has simple, horizontal bands with no vertical
> features. My sparse sampling is collected at striped angles, as you
> can see. I realize that these interpolations aren't 'wrong' per se:
> the way in which they are triangulated strongly affects the final
> result.
>
> Short of re-writing my own triangulation routine, I am wondering if
> there is already a way that I can tell TRIANGULATE to prefer
> triangulation along the x-direction, for example, which in this case
> would solve the problem. Or if there is another built-in routine that
> might work better for me?
>
> I have tried using various Fourier filtering ideas that didn't work
> out as well as I had hoped. I also tried rotating my data-set in
> various ways, triangulating, and then rotating back. So far, those
> ideas haven't worked either.
>

Hello,

I would give IDL's GRIDDATA some scrutiny. For a number of the
sampling methods it offeres you can control its result with either the
ANISOTROPY and SEARCH_ELLIPSE. Once you get the hang of GRIDDATA (and
its companion GRID_INPUT) it can be quite handy.

Cheers,
Ben

Report message to a moderator

[Message index]

		Re: 2D interpolation with sparse data By: Ken G on Wed, 23 May 2007 07:42
		Re: 2D interpolation with sparse data By: cmancone on Wed, 23 May 2007 05:39
		Re: 2D interpolation with sparse data By: ben.bighair on Tue, 22 May 2007 10:06
		Re: 2D interpolation with sparse data By: cmancone on Wed, 23 May 2007 11:58
		Re: 2D interpolation with sparse data By: cmancone on Wed, 23 May 2007 11:57

Previous Topic:	Re: idlwave and emacs "empty input ring"
Next Topic:	Re: Mac Clusters & IDL

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Wed Oct 08 17:55:43 PDT 2025

Total time taken to generate the page: 0.00228 seconds