[Insight-users] GeodesicActiveContours processing time and SignedDanielssonDistanceMap

[Dawood Masslawi]

Hi Ella,
You don't need to use the fastMarching filter if you are using the DanielssonDistanceMap
and vice versa.
If you want to lower the computation time you can decrease the number of iterations or 
assign lower values for the maximum allowed RMS.
The initialDistance parameter is the distance between the seed points and the desired
initial contour.
Also, the following posts on the mailing list can give you more information on how to
control the level of details in your segmentation.
http://www.itk.org/pipermail/insight-users/2011-February/039551.html
http://www.itk.org/pipermail/insight-users/2011-January/039435.html
Note that the assigned Alpha and Beta values for the sigmoid filter can have a significant
effect on the results. It is best to choose the Beta close to the initial contour value and 
assign the Alpha in which an acceptable range of values around the Beta would be
mapped.
Best regards,
Dawood

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Hi, 
I managed to start run the GeodesicActiveContoursFilter. I forgot to the line
fastMarching->SetOutputSize(reader->GetBufferedRegion().GetSize());.
I wanted to use the SignedDanielssonDistanceMapFilter, but i get the same problem as before putting the line above as a result.
Is there something similar for the SignedDanielssonDistanceMapFilter to set?


My second question is regarding the time used for the segmentation
I tried to use it on a MRI t2_3D, 256 slices 40 Iteration steps, but it took me more then 4 minutes. Is this a normal behaviour that i should expect on Leopard 10.6 16 GB RAM?


I still think i am missing something because i don't see a connection between the image and the segmented region. (Which leads me to my third question, what does the DistanceValue in the fastMarching means- it just doesn't make sense to me when starting with a seed point only and not with some initial contour).
I send some images maybe this will help to help me:P
i didn't put all of them, but Test4 is the one where i put my seed point.https://picasaweb.google.com/ellaMkadas/TestLevelSet?authkey=Gv1sRgCMrzgp3nsPfWeg#
Thanks,
Ella


      
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