[Insight-users] vertebrae segmentation with GeodesicActiveContourShapePriorLevelSetFilter

[Juan Cardelino]

Hey Paul,
While I can't assure that this technique would work, I'm pretty
confident that is a good path to follow. However, as they say, the
devil is in the details, so maybe you will need some fine tuning to
make it work.
Regarding the particular problem with the results, I find interesting
to see the final number of iterations in each case. It seems to me
that your problem is that the default maximum number of iterations is
too small. You can tell that because the front stop advancing in a
quite arbritrary point, and not on an actual minimum of the energy.
The second example only confirms my thesis, because the only thing you
did is to increase the propagation speed, which partially aleviates
the problem, but you are still stopping at an arbritrarly point. You
can confirm this by looking at the console output of the program and
see the final number of iterations. If that happens to be the problem,
I suggest that you increase the number of iterations to a ridiculous
number, like 10k, and see at what number it stops. It will be also
useful if you post the output of the program.
I wish you luck with the problem, and let us know how it turned out.
Best regards,
                    Juan

On Sat, Jun 19, 2010 at 10:34 AM, Paul <pare85 at googlemail.com> wrote:
> Hello mailinglist,
>
> I' m using the GeodesicActiveContourShapePriorLevelSetFilter to segment 2D
> ct data of vertebrae. I can't find the right parameters to get a good
> segmentation of the typical vertebra shape. Do you think, it is possible to
> get a good segmentation of vertebrae with the
> GeodesicActiveContourShapePriorLevelSetFilter? The following links show some
> segmentation results, the input image and the mean shape image I'm using.
> Maybe you can give me some advice how I have to change the parameters. I
> tried some parameter combinations but did not get one satisfying result.
>
> input image:
> http://250kb.de/qJsgisV
>
> mean shape image:
> http://250kb.de/e3leuKZ
>
> segmentation result with seed points: 3 propagation=2 advection=3
> curvature=1 shape=0.5 distance=5
>
> http://250kb.de/oamCuus
>
> segmentation result with seed points: 5 propagation=4 advection=3
> curvature=1 shape=0.5 distance=5
>
> http://250kb.de/KyAGhW7
>
>
> Regards
> Paul
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