[Insight-users] vertebrae segmentation with GeodesicActiveContourShapePriorLevelSetFilter

[Paul]

I set the desired final segmentation as initial condition. Here some new 
pictures.


edge map:
http://250kb.de/xJNMujE

new mean shape image and initial condition:
http://250kb.de/9FtvL84

segmentation result:
http://250kb.de/Kwucded

parameter
  - propagation 0.5
  - curvature 1
  - advection 3
  - shape 0.2


Regards
Paul


Am 21.06.2010 14:04, schrieb Juan Cardelino:
> One good thing to try, is to use the desired final segmentation as
> initial condition, and check if the evolution of the curve keeps it in
> place. One interesting thing to see is the edge map, if it is good
> enough it will tell you that you need less weight on the shape term.
> On the contrary, if the boundary map isn't good enough, maybe it is
> wise to raise the weight of the shape term.
> Could you please post the new results? It will be interesting to see
> how it goes.
> Regards,
>               Juan
>
> On Sun, Jun 20, 2010 at 6:25 PM, Paul<pare85 at googlemail.com>  wrote:
>    
>> 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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>>>>          
>>>
>>>        
>>
>>      
>