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

[Luis Ibanez]

Hi Vahid,

You will find information about FFTW at

        http://www.fftw.org/

For installation instructions, please read

    http://www.fftw.org/download.html


If you are using Linux, you can simply install
FFTW as a package.


   Regards,


      Luis


----------------------
vahid taimouri wrote:
> Hi Luis
>  
> Thanks for your regards, but I would like to know how can FTTW be 
> installed? Whether does FFTW need other files to be downloaded?
> Please state more explanation about all things that must be done to run 
> FFTW.
>   
>  
> Thanks
> 
> 
> */Luis Ibanez <luis.ibanez at kitware.com>/* wrote:
> 
> 
>     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
>      > InputFilterType > RescaleFilterType;
>      > typedef itk::VnlFFTRealToComplexConjugateImageFilter< float, 2 >
>      > FFTFilterType;
>      > typedef itk::VnlFFTComplexConjugateToRealImageFilter< float, 2 >
>      > IFFTFilterType;
>      > typedef itk::RescaleIntensityImageFilter
>      > 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();
>      > }
>      >
>      >
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> 
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