[vtkusers] CT Lung Segmentation: Extract Outer Contours

[frederic.salvador at epfl.ch]

Dear all,


So as to segment lungs in CT volume, I implemented the following steps:
    - low-pass smoothing,
    - binary thresolding,
    - connected component analysis,
    - (eventually some objects relabelling).

So now I get a good binary mask of the lung volume.

Though, there are numerous veins and arteries in the lungs volume  
(appearing in black in my binary mask) that I would like to fill.

I tried a rolling-ball operator consisting of a morphological closing  
followed by a hole filling filter. But as my image is 512*512*605 it  
takes too long computation time for my application. Besides, the  
kernel should be pretty big so as to fill big holes.

So here comes my question:
Is it possible:
    - to extract the outer surface, by using marching cubes for  
instance, and fill inside the surface?
OR
    - to extract and operate on 2D slice to extract the outer  
contours, by using some itk or vtk contour filter, and of course fill  
inside the outer contours?


I have been struggling a few hours on this, so your help would be  
highly appreciated.

Thanks a lot in advance for your answer.

Fred