random walker segmentation / blob detection

[Stéfan van der Walt]

Hey Michael

On Tue, Feb 7, 2012 at 4:47 AM, Michael Aye <kmichael.aye at gmail.com> wrote:
> I am searching for the best way of doing blob detection in my noisy
> planetary image data but I just can't find the egg-laying woolen milk-giving
> pig (german proverb) that would solve all my problems, but then again it
> wouldn't be called research, if there's nothing to research, right? ;)

I played around with your images in

http://dip.sun.ac.za/~stefan/dpt/

just to get a feel for what we're dealing with here.  A first result:

http://mentat.za.net/refer/aye_planet0.png
http://mentat.za.net/refer/aye_planet1.png

This technique, specifically, is a non-linear filter, but I think you
should be able to achieve the same with a simpler pipeline:

1) Filter out the image noise
2) Find structures of the appropriate range of sizes in the image
(maybe using difference of Gaussians or other blob detection)
3) Threshold

If you have enough examples of the kind of blobs you're trying to
find, you can train a classifier to set thresholds.  Otherwise, try to
incorporate any knowledge you have from beforehand (i.e., the blobs
are roughly X in size, roughly Y in colour, roughly Z in shape).

Keep us up to date with your progress, and thanks for the interesting
discussion.

Cheers
Stéfan