[Insight-users] vertebrae segmentation with GeodesicActiveContourShapePriorLevelSetFilter

[Paul]

Hello Juan,

thank you for your prompt reply. You are right. The number of iterations 
was too small. The segmentation results are better now but they still 
aren' t good enough. I will try some other parameter combinations, 
create a better mean shape image and check the edge image again. Maybe I 
can optimize some of this things.

Best regards,
Paul

> 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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>