quarticresampler_d.h

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#ifndef AIMS_RESAMPLING_QUARTICRESAMPLER_D_H
#define AIMS_RESAMPLING_QUARTICRESAMPLER_D_H
 
#include <aims/resampling/quarticresampler.h>
 
#include <cmath>
 
 
namespace aims
{
 
template < class T >
QuarticResampler< T >::QuarticResampler()
  : SplineResampler< T >()
{
 
  this->_poles.push_back( std::sqrt( 664.0 - std::sqrt( 438976.0 ) ) +
                          std::sqrt( 304.0 ) - 19.0 );
  this->_poles.push_back( std::sqrt( 664.0 + std::sqrt( 438976.0 ) ) -
                          std::sqrt( 304.0 ) - 19.0 );
  this->_gain = ( 1.0 - this->_poles[ 0 ] ) * ( 1.0 - this->_poles[ 1 ] );
  this->_gain *= this->_gain;
 
}
 
 
template < class T >
QuarticResampler< T >::~QuarticResampler()
{
}
 
 
template < class T >
int QuarticResampler< T >::getOrder() const
{
 
  return 4;
 
}
 
template < class T >
double QuarticResampler< T >::getBSplineWeight( int i, double x ) const
{
 
  x = std::fabs( x - ( double )i );
  if ( x < 0.5 )
  {
 
    x *= x;
    return x * ( x * 0.25 - 0.625 ) + 115.0 / 192.0;
 
  }
  if ( x < 1.5 )
  {
 
    return x * ( x * ( x * ( 5.0 / 6.0 - x * ( 1.0 / 6.0 ) ) - 1.25 ) +
           5.0 / 24.0 ) + 55.0 / 96.0;
 
  }
  if ( x < 2.5 )
  {
 
    x -= 2.5;
    x *= x;
    return x * x * ( 1.0 / 24.0 );
 
  }
  return 0.0;
 
}
 
} // namespace aims
 
#endif