[Insight-users] Segmentation issue ( in level set techniques)

[Sotiris Dimopoulos]

Hello to everybody!

I have a pack of slices of the humerus bone (in dicom
format) and I want to segment, in each slice, the
surface inside the bone. The area inside the bone and
outside the bone has no intensity difference (it is
black everywhere apart from the pixels that represent
the bone, which are white). So, imagine a black
picture that has something that looks like a white
circle somewhere in the middle.

I want the procedure to be automatic in each slice (so
I can’t use stuff like position-seeds) and as a result
the region growing techniques don’t fit. Moreover, I
have no intensity difference inside and outside the
bone, so methods like watersheds (and generally
intensity-based methods) do not seem appropriate. 

I try to use "level set segmentation" techniques but I
can’t find an automatic way of computing the zero
level set function. Of course, I want to take
advantage of the edges of the bone and I wish these
white contours that I have to represent the zero level
set function. 

1) How can I "automatically" extract the initial model

Ψ(Χ,t=0) that these filters need as an input from each
dicom slice (feature images)?
   
2) Which filters do you believe will help me solve my
problem?


 Many thanks in advance
          Sotiris


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