[vtk-developers] A couple new classes

[Lorensen, William E (CRD)]

David,
I checked in test images for your new classes. They seem to fail on multiprocessor systems.

Bill

-----Original Message-----
From: David Gobbi [mailto:dgobbi at irus.rri.ca]
Sent: Tuesday, July 03, 2001 11:46 AM
To: vtk-developers at public.kitware.com
Subject: [vtk-developers] A couple new classes


I've committed a new vtkImageStencil class for doing cookie-cutter type
operations on vtkImageData.  Most of the stencil functionality is
actually provided by a support class, vtkImageClippingExtents, because
I also want to allow support for stencil operations inside vtkImageReslice
but want to avoid code duplication.

The 'helper' class vtkImageClippingExtents describes an image mask in
the form of a sparse array (sparse only in the x-dimension).  Right now
this class is derived directly from vtkObject, but I plan to make it
a descendant of vtkDataObject and add a 'Source' type for it.  In the
end this will mean a fairly large number of classes just to support
just a single function (a stencil).  And all just so that I can do
stenciling in vtkImageReslice instead of just inside vtkImageStencil!

So I'd better provide some justification.  The reason I want to stencil
with vtkImageReslice is to make nonlinear image registration more
efficient: I want to precisely stencil out the portion of the anatomy to
which the (rather expensive) warp transformations are applied.  Using a
sparse array to describe the stencil is more space & time efficient than
using a pixel mask, and also minimizes the changes that have to be made
to vtkImageReslice.cxx (which is already quite bloated).

As a final note, The new class contrib/vtkImagePolyDataClippingExtents
provides the means to use a closed, non-self-intersecting vtkPolyData
surface as a stencil.  Its name will probably be changed in the future.

 - David

--
  David Gobbi, MSc                       dgobbi at irus.rri.ca
  Advanced Imaging Research Group
  Robarts Research Institute, University of Western Ontario


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