vnl_fft_2d.h

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#ifndef vnl_fft_2d_h_
#define vnl_fft_2d_h_
/*
  fsm@robots.ox.ac.uk
*/

//: In-place 2D fast fourier transform.

#include <vnl/vnl_matrix.h>
#include <vnl/algo/vnl_fft_base.h>

template <class T>
struct vnl_fft_2d : vnl_fft_base<2, T>
{
  typedef vnl_fft_base<2, T> base;
  
  //: constructor takes size of signal.
  vnl_fft_2d(int M, int N) {
    base::factors_[0].resize(M);
    base::factors_[1].resize(N);
  }
  
  //: dir = +1/-1 according to direction of transform.
  void transform(vnl_matrix<vcl_complex<T> > &signal, int dir)
  { base::transform(signal.data_block(), dir); }
  
  //: forward FFT
  void fwd_transform(vnl_matrix<vcl_complex<T> > &signal)
  { transform(signal, +1); }
  
  //: backward (inverse) FFT
  void bwd_transform(vnl_matrix<vcl_complex<T> > &signal)
  { transform(signal, -1); }
  
  //: return size of signal.
  unsigned rows() const { return base::factors_[0].number(); }
  unsigned cols() const { return base::factors_[1].number(); }
};

#endif

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