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/*=========================================================================
Program: Visualization Toolkit
Module: vtkGaussianKernel.h
Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
All rights reserved.
See Copyright.txt or http://www.kitware.com/Copyright.htm for details.
This software is distributed WITHOUT ANY WARRANTY; without even
the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE. See the above copyright notice for more information.
=========================================================================*/
/**
* @class vtkGaussianKernel
* @brief a spherical Gaussian interpolation kernel
*
*
* vtkGaussianKernel is an interpolation kernel that simply returns the
* weights for all points found in the sphere defined by radius R. The
* weights are computed as: exp(-(s*r/R)^2) where r is the distance from the
* point to be interpolated to a neighboring point within R. The sharpness s
* simply affects the rate of fall off of the Gaussian. (A more general
* Gaussian kernel is available from vtkEllipsoidalGaussianKernel.)
*
* @warning
* The weights are normalized sp that SUM(Wi) = 1. If a neighbor point p
* precisely lies on the point to be interpolated, then the interpolated
* point takes on the values associated with p.
*
* @sa
* vtkPointInterpolator vtkInterpolationKernel vtkEllipsoidalGaussianKernel
* vtkVoronoiKernel vtkSPHKernel vtkShepardKernel
*/
#ifndef vtkGaussianKernel_h
#define vtkGaussianKernel_h
#include "vtkFiltersPointsModule.h" // For export macro
#include "vtkGeneralizedKernel.h"
class vtkIdList;
class vtkDoubleArray;
class VTKFILTERSPOINTS_EXPORT vtkGaussianKernel : public vtkGeneralizedKernel
{
public:
//@{
/**
* Standard methods for instantiation, obtaining type information, and printing.
*/
static vtkGaussianKernel *New();
vtkTypeMacro(vtkGaussianKernel,vtkGeneralizedKernel);
void PrintSelf(ostream& os, vtkIndent indent);
//@}
/**
* Initialize the kernel. Overload the superclass to set up internal
* computational values.
*/
virtual void Initialize(vtkAbstractPointLocator *loc, vtkDataSet *ds,
vtkPointData *pd);
// Re-use any superclass signatures that we don't override.
using vtkGeneralizedKernel::ComputeWeights;
/**
* Given a point x, a list of basis points pIds, and a probability
* weighting function prob, compute interpolation weights associated with
* these basis points. Note that basis points list pIds, the probability
* weighting prob, and the weights array are provided by the caller of the
* method, and may be dynamically resized as necessary. The method returns
* the number of weights (pIds may be resized in some cases). Typically
* this method is called after ComputeBasis(), although advanced users can
* invoke ComputeWeights() and provide the interpolation basis points pIds
* directly. The probably weighting prob are numbers 0<=prob<=1 which are
* multiplied against the interpolation weights before normalization. They
* are estimates of local confidence of weights. The prob may be NULL in
* which all probabilities are considered =1.
*/
virtual vtkIdType ComputeWeights(double x[3], vtkIdList *pIds,
vtkDoubleArray *prob, vtkDoubleArray *weights);
//@{
/**
* Set / Get the sharpness (i.e., falloff) of the Gaussian. By default
* Sharpness=2. As the sharpness increases the effects of distant points
* are reduced.
*/
vtkSetClampMacro(Sharpness,double,1,VTK_FLOAT_MAX);
vtkGetMacro(Sharpness,double);
//@}
protected:
vtkGaussianKernel();
~vtkGaussianKernel();
double Sharpness;
// Internal structure to reduce computation
double F2;
private:
vtkGaussianKernel(const vtkGaussianKernel&) VTK_DELETE_FUNCTION;
void operator=(const vtkGaussianKernel&) VTK_DELETE_FUNCTION;
};
#endif
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