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CoscotFunction< T > Class Template Reference

#include <vigra/resizeimage.hxx>

List of all members.

Public Types

typedef T argument_type
typedef T result_type
typedef T value_type

Public Member Functions

unsigned int derivativeOrder () const
result_type operator() (argument_type x) const
value_type operator[] (value_type x) const
ArrayVector< double > const & prefilterCoefficients () const
double radius () const

Detailed Description

template<class T>
class vigra::CoscotFunction< T >

The Coscot interpolation function.

Implements the Coscot interpolation function proposed by Maria Magnusson Seger (maria@isy.liu.se) in the context of tomographic reconstruction. It provides a fast transition between the pass- and stop-bands and minimal ripple outside the transition region. Both properties are important for this application and can be tuned by the parameters m and h (with defaults 3 and 0.5). The function is defined by

\[ f_{m,h}(x) = \left\{ \begin{array}{ll} \frac{1}{2m}\sin(\pi x)\cot(\pi x / (2 m))(h + (1-h)\cos(\pi x/m)) & |x| \leq m \\ 0 & \mbox{otherwise} \end{array}\right. \]

It can be used as a functor, and as a kernel for resamplingConvolveImage() to create a differentiable interpolant of an image.

#include <vigra/resizeimage.hxx>
Namespace: vigra


Member Typedef Documentation

typedef T value_type

the kernel's value type

typedef T argument_type

the unary functor's argument type

typedef T result_type

the splines polynomial order


Member Function Documentation

result_type operator() ( argument_type  x) const

function (functor) call

value_type operator[] ( value_type  x) const

index operator -- same as operator()

double radius ( ) const

Radius of the function's support. Needed for resamplingConvolveImage(), equals m.

unsigned int derivativeOrder ( ) const

Derivative order of the function: always 0.

ArrayVector<double> const& prefilterCoefficients ( ) const

Prefilter coefficients for compatibility with vigra::BSpline. (array has zero length, since prefiltering is not necessary).


The documentation for this class was generated from the following file:

© Ullrich Köthe (ullrich.koethe@iwr.uni-heidelberg.de)
Heidelberg Collaboratory for Image Processing, University of Heidelberg, Germany

html generated using doxygen and Python
vigra 1.7.0 (Thu Aug 25 2011)