[Insight-users] I have a problem With FFT in ITK

[Luis Ibanez]

Hi Vahid,


Yes, this is a known problem with the VNL implementation of FFT.


You may want to install FFTW in your system and rerun CMake in
ITK in order to specify that you want to use FFTW. This is
currently an advanced option in the CMake configuration of ITK.


   Regards,


      Luis



---------------------------
vahid taimouri wrote:
> Hi all
> I tried to use FFT to build an ideal lowpass filter
> But I think FFT doesn't work correctly,
> Also I applied the FFT to an image and then the inverse FFT to its result
> But surprisingly it didn't retrieve my image!!!
>  
> I added my codes here, please guild to solve this problem
> Thanks
>  
>  void main()
> {  
>  char InputImageName[30] = "Inputimage.bmp";
>  char OutputImageName[30] = "OutputImage.bmp";
>  
>  typedef itk::Image< unsigned char, 2 > InputImageType;
>  typedef itk::Image< unsigned char, 2 > OutputImageType;
>  
>  typedef itk::Image< float, 2 > InputFilterType;
>  typedef itk::Image< float, 2 > OutputFilterType;
>  
>  typedef itk::ImageFileReader< InputImageType > ReaderType;
>  typedef itk::RescaleIntensityImageFilter<InputImageType, 
> InputFilterType > RescaleFilterType;
>  typedef itk::VnlFFTRealToComplexConjugateImageFilter< float, 2 > 
> FFTFilterType;
>  typedef itk::VnlFFTComplexConjugateToRealImageFilter< float, 2 > 
> IFFTFilterType;
>  typedef itk::RescaleIntensityImageFilter<InputFilterType, 
> OutputImageType > RescaleFilterType;
>  typedef itk::ImageFileWriter< OutputImageType > WriterType;
>  ReaderType::Pointer reader = ReaderType::New();
>  InputRescaleFilterType::Pointer inputintensityrescaler = 
> InputRescaleFilterType::New();
>  FFTFilterType::Pointer fftFilter = FFTFilterType::New(); 
>  IFFTFilterType::Pointer fftInverseFilter = IFFTFilterType::New();
>  OutputRescaleFilterType::Pointer outputintensityrescaler = 
> OutputRescaleFilterType::New();
>  WriterType::Pointer writer = WriterType::New();
>  
>  Inputintensityrescaler->SetOutputMinimum(  0  );
>  Inputintensityrescaler->SetOutputMaximum( 255 );
>  
>  Outputintensityrescaler->SetOutputMinimum(  0  );
>  Outputintensityrescaler->SetOutputMaximum( 255 );
>  
>  reader->SetFileName( InputImageName );
>  writer->SetFileName( OutputImageName );
>  reader->Update();
>  
>  inputintensityrescaler->SetInput( reader->GetOutput() );
>  fftFilter->SetInput( inputintensityrescaler->GetOutput() );
>  fftFilter->Update();
>  
>  fftInverseFilter->SetInput( fftFilter->GetOutput() );
>  
>  typedef itk::FlipImageFilter< InputFilterType > FlipperType;
>  FlipperType::Pointer flipper = FlipperType::New();
>  bool fliparray[2] = {true,true};
>  FlipperType::FlipAxesArrayType flipAxes( fliparray );
>  flipper->SetFlipAxes(flipAxes);
>  flipper->SetInput(fftInverseFilter->GetOutput());
> 
>  
>  Outputintensityrescaler->SetInput( flipper->GetOutput() );
> 
>  writer->SetInput(Outputintensityrescaler->GetOutput());
>  writer->Update();
> }
> 
> ------------------------------------------------------------------------
> Do you Yahoo!?
> Everyone is raving about the all-new Yahoo! Mail Beta. 
> <http://us.rd.yahoo.com/evt=42297/*http://advision.webevents.yahoo.com/handraisers> 
> 
> 
> 
> ------------------------------------------------------------------------
> 
> _______________________________________________
> Insight-users mailing list
> Insight-users at itk.org
> http://www.itk.org/mailman/listinfo/insight-users