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From: "Sven" <sven.holcombe@gmail.deleteme.com>
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Subject: How to attack a local minima problem?
Date: Sat, 22 Nov 2008 16:42:02 +0000 (UTC)
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Hi all,

I have a problem that I can boil down to an image such as:
http://tinypic.com/view.php?pic=wirhxt&s=4

Here you see 9 fairly regularly spaced minima, with a little bit of smearing from one to the next. I'm trying to write something to automatically locate each of these minima. I have the image processing toolbox at my disposal.

I have attacked this problem a few different ways, but none to my satisfaction just yet.

If I use imregionalmin, I get a scattering of local minima, but no simple way to return only these 9 minima that I'm looking for. If I simply choose the 9 minima regions having the lowest average pixel value, I almost always get multiple hits returned in just some of the minima you see in the image.

Conceptually, I would like to 'hang' a chain of links/joints down my image. Each joint is attracted to pixels with lower values (ie, will merge towards minima), and each link is essentially a spring of some length (about the average distance between the minima I'm searching for).

Am I overthinking this? Can anyone help point me towards an algorithm I could adopt for the problem? Can anyone help me just *name* my problem so that I know what i should be searching for?

Thanks very much,
Sven.