ExampleFFT2D_free.cpp

Example for using the fast fourier Transform (FFT)

Author

MIP

/* This file is part of the BIAS library (Basic ImageAlgorithmS).

   Copyright (C) 2003-2009    (see file CONTACT for details)
   Multimediale Systeme der Informationsverarbeitung
   Institut fuer Informatik
   Christian-Albrechts-Universitaet Kiel
   
   
   BIAS is free software; you can redistribute it and/or modify
   it under the terms of the GNU Lesser General Public License as published by
   the Free Software Foundation; either version 2.1 of the License, or
   (at your option) any later version.
   
   BIAS is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU Lesser General Public License for more details.
   
   You should have received a copy of the GNU Lesser General Public License
   along with BIAS; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA*/


/**
 * @example ExampleFFT2D_free.cpp
   @relates FFT2D_free
   @brief Example for using the fast fourier Transform (FFT)
   @ingroup g_examples
   @author  MIP
*/

#include <Image/FFT2D_free.hh>
#include <Base/Image/Image.hh>
#include <Base/Image/ImageIO.hh>
#include <Base/Image/ImageConvert.hh>
#include <Base/Debug/TimeMeasure.hh>

using namespace std;
using namespace BIAS;


int main(int argc, char *argv[])
{
  TimeMeasure StopWatch;
  Image<unsigned char> im1, im1grey,res;

  if (argc<2){
    im1grey.Init(160,120,1);
    im1grey.FillImageWithXValue();
  }
  else {
    if (ImageIO::Load(argv[1], im1)!=0){
      BIASERR("error loading image "<<argv[1]);
      return -2;
    }
    ImageConvert::ToGrey(im1,im1grey);
  }


  ImageIO::Save("FFT2D_free_Grey1",im1grey);
  cout <<"Image dimensions: "<<im1grey.GetWidth()<<"x"<<im1grey.GetHeight()<<endl;

  FFT2D_free< unsigned char> fft;
 
  Image<float> complex,value;

  // warm-up
  fft.Forward(im1grey,complex);
  fft.Forward(im1grey,complex);
  fft.Forward(im1grey,complex);

  StopWatch.Start();
//  for (unsigned int i=0;i<100;i++)
    fft.Forward(im1grey,complex);
  StopWatch.Stop();
  cout <<"FFT Forward took [ms] :"<<StopWatch.GetRealTime()/1000/100<<endl;;
  ImageIO::Save("FFT2D_free_Spectrum_complex",complex);

   //fft.Normalize(complex);

   StopWatch.Reset();
  StopWatch.Start();
  fft.GetMagnitude(complex,value);
  StopWatch.Stop();
  cout <<"FFT GetValue took [ms] :"<<StopWatch.GetRealTime()/1000<<endl;;
  ImageIO::Save("FFT2D_free_Spectrum_value",value);

  //fft.Normalize(complex);
  ImageIO::Save("FFT2D_free_Spectrum_normalized",complex);



  fft.Reverse(complex,res);
  Image<unsigned char> resRGB(im1grey.GetWidth(), im1grey.GetHeight(), 3);
  ImageConvert::ToRGB(res, resRGB);
  ImageIO::Save("FFT2D_free_Reverse",resRGB);


  return 0;
}