/*=========================================================================

  Program:   Visualization Toolkit
  Module:    vtkImageVariance3D.h
  Language:  C++
  Date:      $Date$
  Version:   $Revision$
  Thanks:    Thanks to C. Charles Law who developed this class.

Copyright (c) 1993-2001 Ken Martin, Will Schroeder, Bill Lorensen 
All rights reserved.

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modification, are permitted provided that the following conditions are met:

 * Redistributions of source code must retain the above copyright notice,
   this list of conditions and the following disclaimer.

 * Redistributions in binary form must reproduce the above copyright notice,
   this list of conditions and the following disclaimer in the documentation
   and/or other materials provided with the distribution.

 * Neither name of Ken Martin, Will Schroeder, or Bill Lorensen nor the names
   of any contributors may be used to endorse or promote products derived
   from this software without specific prior written permission.

 * Modified source versions must be plainly marked as such, and must not be
   misrepresented as being the original software.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS''
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

=========================================================================*/
// .NAME vtkImageVariance3D - Variance in a neighborhood.
// .SECTION Description
// vtkImageVariance3D replaces each pixel with a measurement of 
// pixel variance in a elliptical neighborhood centered on that pixel.
// The value computed is not exactly the variance.
// The difference between the neighbor values and center value is computed
// and squared for each neighbor.  These values are summed and divided by
// the total number of neighbors to produce the output value.


#ifndef __vtkImageVariance3D_h
#define __vtkImageVariance3D_h


#include "vtkImageSpatialFilter.h"

class vtkImageEllipsoidSource;

class VTK_EXPORT vtkImageVariance3D : public vtkImageSpatialFilter
{
public:
  static vtkImageVariance3D *New();
  vtkTypeMacro(vtkImageVariance3D,vtkImageSpatialFilter);
  void PrintSelf(ostream& os, vtkIndent indent);
  
  // Description:
  // This method sets the size of the neighborhood.  It also sets the default
  // middle of the neighborhood and computes the Elliptical foot print.
  void SetKernelSize(int size0, int size1, int size2);
  
protected:
  vtkImageVariance3D();
  ~vtkImageVariance3D();
  vtkImageVariance3D(const vtkImageVariance3D&) {};
  void operator=(const vtkImageVariance3D&) {};

  vtkImageEllipsoidSource *Ellipse;
    
  void ExecuteInformation(vtkImageData *inData, vtkImageData *outData);
  void ExecuteInformation(){this->vtkImageToImageFilter::ExecuteInformation();};
  void ThreadedExecute(vtkImageData *inData, vtkImageData *outData, 
		       int extent[6], int id);
};

#endif



