ITK  5.0.0
Insight Segmentation and Registration Toolkit
Examples/Filtering/FFTDirectInverse2.cxx
/*=========================================================================
*
* Copyright Insight Software Consortium
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0.txt
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
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*=========================================================================*/
#include "itkConfigure.h"
//
// This example is based on the on that was contributed by Stephan in the users list
//
// http://public.kitware.com/pipermail/insight-users/2005-June/013482.html
//
//
// Software Guide : BeginLatex
//
// This example illustrates how to compute the direct Fourier transform
// followed by the inverse Fourier transform using the FFTW library.
//
// Software Guide : EndLatex
#include "itkImage.h"
#if !defined(ITK_USE_FFTWF)
//#error "This example only works when single precision FFTW is used
//Changing WorkPixeltype to double and changing this conditional to ITK_USE_FFTWD
//will also work.
#endif
int main( int argc, char * argv[] )
{
if( argc != 3 )
{
std::cerr << "Usage: " << argv[0] << " input output" << std::endl;
return EXIT_FAILURE;
}
// Software Guide : BeginLatex
//
// First we set up the types of the input and output images.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
constexpr unsigned int Dimension = 2;
// using OutputPixelType = unsigned char;
using OutputPixelType = unsigned short;
using WorkPixelType = float;
using OutputImageType = itk::Image< OutputPixelType,Dimension >;
// Software Guide : EndCodeSnippet
// File handling
ReaderType::Pointer inputreader = ReaderType::New();
WriterType::Pointer writer = WriterType::New();
inputreader->SetFileName( argv[1] );
writer->SetFileName( argv[2] );
// Read the image and get its size
inputreader->Update();
// Forward FFT filter
FFTFilterType::Pointer fftinput = FFTFilterType::New();
fftinput->SetInput( inputreader->GetOutput() );
fftinput->Update();
// This is the output type from the FFT filters
using ComplexImageType = FFTFilterType::OutputImageType;
// Do the inverse transform = forward transform + flip all axes
invFFTFilterType::Pointer fftoutput = invFFTFilterType::New();
fftoutput->SetInput(fftinput->GetOutput()); // try to recover the input image
fftoutput->Update();
// Rescale the output to suit the output image type
using RescaleFilterType = itk::RescaleIntensityImageFilter<
WorkImageType,
OutputImageType >;
RescaleFilterType::Pointer intensityrescaler = RescaleFilterType::New();
std::cout << fftoutput->GetOutput()->GetLargestPossibleRegion().GetSize() << std::endl;
intensityrescaler->SetInput( fftoutput->GetOutput() );
intensityrescaler->SetOutputMinimum( 0 );
intensityrescaler->SetOutputMaximum( 65535 );
// Write the output
writer->SetInput(intensityrescaler->GetOutput());
writer->Update();
//DEBUG: std::cout << "inputreader "<<inputreader->GetOutput()->GetLargestPossibleRegion().GetSize() << std::endl;
//DEBUG: std::cout << "fftinput " <<fftinput->GetOutput()->GetLargestPossibleRegion().GetSize() << std::endl;
//DEBUG: std::cout << "fftoutput " <<fftoutput->GetOutput()->GetLargestPossibleRegion().GetSize() << std::endl;
//DEBUG: std::cout << "intensityrescaller " <<intensityrescaler->GetOutput()->GetLargestPossibleRegion().GetSize() << std::endl;
return EXIT_SUCCESS;
}