[vtkusers] extracting exterior bone surfaces

[Goodwin Lawlor]

One image pre-processing method that may work is "Opening" - erosion (to
break the connecting voxels) followed by dilation (to fill volume back out
again). The classes vtkImageContinuousErode3D & vtkImageContinuousDilate3D
in series before a mcubes filter (and gaussiansmooth filter) would do it.
vtkImageDilateErode3D on its own may do it...


-----Original Message-----
From: vtkusers-admin at public.kitware.com
[mailto:vtkusers-admin at public.kitware.com]On Behalf Of Will Newman
Sent: 28 March 2001 21:00
To: vtkusers at public.kitware.com
Subject: [vtkusers] extracting exterior bone surfaces


We import volumetric CT data into VTK to create bone surfaces using
marching cubes.  We are looking for ways to extract only the external
bone surfaces, but are having problems eliminating the inside bone
surface. There are two main surfaces, the endosteal and periosteal
surfaces of the bone.  We have used thresholding to isolate a nice
binary image but because of small interconnections between the surfaces
we are unable to isolate the periosteal (exterior) surface by using the
connectivity filter.  Is there any way we can further preprocess the
image data to obtain just the exterior ring of voxels *before* running
marching cubes?  Or, are there other strategies we can use to isolate
just the exterior surface *after* running marching cubes?

Thanks.

--
Will Newman
Musculoskeletal Research Laboratories
University of Utah
wjn1 at utah.edu   http://hodad.bioen.utah.edu/~weiss/mrl



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