
 Usage

vtkFiniteDifferenceGradientEstimator is a concrete subclass
of vtkEncodedGradientEstimator that uses a central
differences technique to estimate the gradient. The gradient
at some sample location (x,y,z) would be estimated by:

   nx = (f(x-dx,y,z) - f(x+dx,y,z)) / 2*dx;
   ny = (f(x,y-dy,z) - f(x,y+dy,z)) / 2*dy;
   nz = (f(x,y,z-dz) - f(x,y,z+dz)) / 2*dz;

This value is normalized to determine a unit direction
vector and a magnitude. The normal is computed in voxel
space, and dx = dy = dz = SampleSpacingInVoxels. A scaling
factor is applied to convert this normal from voxel space to
world coordinates.
To create an instance of class
vtkFiniteDifferenceGradientEstimator, simply invoke its
constructor as follows

    obj = vtkFiniteDifferenceGradientEstimator



 Methods

The class vtkFiniteDifferenceGradientEstimator has several
methods that can be used. They are listed below. Note that
the documentation is translated automatically from the VTK
sources, and may not be completely intelligible. When in
doubt, consult the VTK website. In the methods listed below,
obj is an instance of the
vtkFiniteDifferenceGradientEstimator class.

* string = obj.GetClassName ()
* int = obj.IsA (string name)
* vtkFiniteDifferenceGradientEstimator = obj.NewInstance ()
* vtkFiniteDifferenceGradientEstimator = obj.SafeDownCast
  (vtkObject o)
* obj.SetSampleSpacingInVoxels (int ) - Set/Get the spacing
  between samples for the finite differences method used to
  compute the normal. This spacing is in voxel units.
* int = obj.GetSampleSpacingInVoxels () - Set/Get the
  spacing between samples for the finite differences method
  used to compute the normal. This spacing is in voxel
  units.


* FreeMat_Documentation
* Visualization_Toolkit_Volume_Rendering_Classes
* Generated on Thu Jul 25 2013 17:18:36 for FreeMat by
  doxygen_ 1.8.1.1

