SubsampleVolume-alex.cxx

// Alex Chekholko 2006-01-19 // based on SubsampleVolume.cxx // should simply interpolate the input image with the given parameters // using the WindowedSincInterpolateImageFunction with radius 5 and Welch window #if defined(_MSC_VER) #pragma warning ( disable : 4786 ) #endif #ifdef __BORLANDC__ #define ITK_LEAN_AND_MEAN #endif #include "itkImage.h" #include "itkImageFileReader.h" #include "itkImageFileWriter.h" #include "itkCastImageFilter.h" #include "itkResampleImageFilter.h" #include "itkIdentityTransform.h" #include "itkWindowedSincInterpolateImageFunction.h" #include "itkConstantBoundaryCondition.h" int main( int argc, char * argv[] ) { if( argc < 6 ) { std::cerr << "Usage: " << std::endl; std::cerr << argv[0] << " inputImageFile outputImageFile factorX factorY factorZ" << std::endl; return EXIT_FAILURE; } const unsigned int Dimension = 3; typedef unsigned char InputPixelType; typedef float InternalPixelType; typedef unsigned char OutputPixelType; typedef itk::Image< InputPixelType, Dimension > InputImageType; typedef itk::Image< InternalPixelType, Dimension > InternalImageType; typedef itk::Image< OutputPixelType, Dimension > OutputImageType; // read in the file typedef itk::ImageFileReader< InputImageType > ReaderType; ReaderType::Pointer reader = ReaderType::New(); reader->SetFileName( argv[1] ); const double factorX = atof( argv[3] ); const double factorY = atof( argv[4] ); const double factorZ = atof( argv[5] ); try { reader->Update(); } catch( itk::ExceptionObject & excep ) { std::cerr << "Exception caught while reading input file!" << std::endl; std::cerr << excep << std::endl; } InputImageType::ConstPointer inputImage = reader->GetOutput(); const InputImageType::SpacingType& inputSpacing = inputImage->GetSpacing(); // A casting filter is instantiated in order to convert the pixel type of the // input image into the pixel type desired for computing the resampling. typedef itk::CastImageFilter< InputImageType, InternalImageType > CastFilterType; CastFilterType::Pointer caster = CastFilterType::New(); caster->SetInput( inputImage ); typedef itk::ResampleImageFilter< InternalImageType, OutputImageType > ResampleFilterType; ResampleFilterType::Pointer resampler = ResampleFilterType::New(); // Since the resampling is performed in the same physical extent of the input // image, we select the IdentityTransform as the one to be used by the resampling // filter. typedef itk::IdentityTransform< double, Dimension > TransformType; TransformType::Pointer transform = TransformType::New(); transform->SetIdentity(); resampler->SetTransform( transform ); const unsigned int WindowRadius = 5; typedef itk::Function::WelchWindowFunction< WindowRadius > WindowFunctionType; // by default, the constant = 0 typedef itk::ConstantBoundaryCondition< InternalImageType > BoundaryConditionType; typedef itk::WindowedSincInterpolateImageFunction<InternalImageType, WindowRadius, WindowFunctionType, BoundaryConditionType, double> InterpolatorType; InterpolatorType::Pointer interpolator = InterpolatorType::New(); resampler->SetInterpolator( interpolator ); resampler->SetDefaultPixelValue( 0 ); // value for regions without source OutputImageType::SpacingType spacing; spacing[0] = inputSpacing[0] * factorX; spacing[1] = inputSpacing[1] * factorY; spacing[2] = inputSpacing[2] * factorZ; resampler->SetOutputSpacing( spacing ); // The origin of the input image is preserved and passed to the output image. resampler->SetOutputOrigin( inputImage->GetOrigin() ); // The number of pixels to use along each direction on the grid of the // resampled image is computed using the number of pixels in the input image // and the sampling factors. InputImageType::SizeType inputSize = inputImage->GetLargestPossibleRegion().GetSize(); typedef InputImageType::SizeType::SizeValueType SizeValueType; InputImageType::SizeType size; size[0] = static_cast< SizeValueType >( inputSize[0] / factorX ); size[1] = static_cast< SizeValueType >( inputSize[1] / factorY ); size[2] = static_cast< SizeValueType >( inputSize[2] / factorZ ); resampler->SetSize( size ); //connect to the pipeline resampler->SetInput( caster->GetOutput() ); typedef itk::ImageFileWriter< OutputImageType > WriterType; WriterType::Pointer writer = WriterType::New(); writer->SetInput( resampler->GetOutput() ); writer->SetFileName( argv[2] ); try { writer->Update(); } catch( itk::ExceptionObject & excep ) { std::cerr << "Exception caught!" << std::endl; std::cerr << excep << std::endl; } // std::cout << "Resampling Done !" << std::endl; return EXIT_SUCCESS; }