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| <div class="floatcenter">[[File:ITK_Examples_Baseline_ImageProcessing_TestResampleSegmentedImage.png]]</div>
| | {{warning|1=The media wiki content on this page is no longer maintained. The examples presented on the https://itk.org/Wiki/* pages likely require ITK version 4.13 or earlier releases. In many cases, the examples on this page no longer conform to the best practices for modern ITK versions. |
| ==ResampleSegmentedImage.cxx==
| | }} |
| <source lang="cpp">
| |
| #include "itkImage.h"
| |
| #include "itkImageFileReader.h"
| |
| #include "itkIdentityTransform.h"
| |
| #include "itkLabelImageGaussianInterpolateImageFunction.h"
| |
| #include "itkNearestNeighborInterpolateImageFunction.h"
| |
| #include "itkResampleImageFilter.h"
| |
| | |
| #include "itkCustomColormapFunction.h"
| |
| #include "itkScalarToRGBColormapImageFilter.h"
| |
| #include "itkRGBPixel.h"
| |
| #include "itkMersenneTwisterRandomVariateGenerator.h"
| |
| | |
| #include "QuickView.h"
| |
| | |
| #include <iostream>
| |
|
| |
| typedef unsigned short InputPixelType;
| |
| typedef itk::Image<InputPixelType, 2> ImageType;
| |
| typedef itk::RGBPixel<unsigned char> RGBPixelType;
| |
| typedef itk::Image<RGBPixelType, 2> RGBImageType;
| |
| | |
| typedef itk::Function::CustomColormapFunction<
| |
| ImageType::PixelType, RGBImageType::PixelType> ColormapType;
| |
| | |
| static void CreateRandomColormap(unsigned int size, ColormapType::Pointer colormap);
| |
| | |
| int main( int argc, char * argv[] )
| |
| { | |
| if( argc != 3 )
| |
| {
| |
| std::cerr << "Usage: " << argv[0]
| |
| << " inputImageFile pixelSize"
| |
| << std::endl;
| |
|
| |
| return EXIT_FAILURE;
| |
| }
| |
| double spacing = atof(argv[2]);
| |
|
| |
| typedef itk::ImageFileReader<ImageType> ReaderType;
| |
|
| |
| // Identity transform.
| |
| // We don't want any transform on our image except rescaling which is not
| |
| // specified by a transform but by the input/output spacing as we will see
| |
| // later.
| |
| // So no transform will be specified.
| |
| typedef itk::IdentityTransform<double, 2>
| |
| TransformType;
| |
|
| |
| typedef itk::LabelImageGaussianInterpolateImageFunction<ImageType, double>
| |
| GaussianInterpolatorType;
| |
| typedef itk::NearestNeighborInterpolateImageFunction<ImageType, double>
| |
| NearestNeighborInterpolatorType;
| |
| | |
| typedef itk::ResampleImageFilter<ImageType, ImageType>
| |
| ResampleFilterType;
| |
| | |
| // Prepare the reader and update it right away to know the sizes beforehand.
| |
| ReaderType::Pointer reader =
| |
| ReaderType::New();
| |
| reader->SetFileName( argv[1] );
| |
| reader->Update();
| |
|
| |
| // Instantiate the transform and specify it should be the identity transform.
| |
| TransformType::Pointer transform =
| |
| TransformType::New();
| |
| transform->SetIdentity();
| |
|
| |
| // Instantiate the interpolators
| |
| GaussianInterpolatorType::Pointer gaussianInterpolator =
| |
| GaussianInterpolatorType::New();
| |
| gaussianInterpolator->SetSigma(1.0);
| |
| gaussianInterpolator->SetAlpha(3.0);
| |
| | |
| NearestNeighborInterpolatorType::Pointer nearestNeighborInterpolator =
| |
| NearestNeighborInterpolatorType::New();
| |
|
| |
| // Instantiate the resamplers. Wire in the transforms and the interpolators.
| |
| ResampleFilterType::Pointer resizeFilter1 =
| |
| ResampleFilterType::New();
| |
| resizeFilter1->SetTransform(transform);
| |
| resizeFilter1->SetInterpolator(gaussianInterpolator);
| |
| | |
| ResampleFilterType::Pointer resizeFilter2 =
| |
| ResampleFilterType::New();
| |
| resizeFilter2->SetTransform(transform);
| |
| resizeFilter2->SetInterpolator(nearestNeighborInterpolator);
| |
|
| |
| // Compute and set the output size
| |
| //
| |
| // The computation must be so that the following holds:
| |
| //
| |
| // new width old x spacing
| |
| // ---------- = ---------------
| |
| // old width new x spacing
| |
| //
| |
| //
| |
| // new height old y spacing
| |
| // ------------ = ---------------
| |
| // old height new y spacing
| |
| //
| |
| // So either we specify new height and width and compute new spacings
| |
| // or we specify new spacing and compute new height and width
| |
| // and computations that follows need to be modified a little (as it is
| |
| // done at step 2 there:
| |
| // http://itk.org/Wiki/ITK/Examples/DICOM/ResampleDICOM)
| |
| //
| |
| | |
| // Fetch original image spacing.
| |
| const ImageType::SpacingType& inputSpacing =
| |
| reader->GetOutput()->GetSpacing();
| |
|
| |
| double outputSpacing[2];
| |
| outputSpacing[0] = spacing;
| |
| outputSpacing[1] = spacing;
| |
|
| |
| // Fetch original image size
| |
| const ImageType::RegionType& inputRegion =
| |
| reader->GetOutput()->GetLargestPossibleRegion();
| |
| const ImageType::SizeType& inputSize = inputRegion.GetSize();
| |
| unsigned int oldWidth = inputSize[0]; | |
| unsigned int oldHeight = inputSize[1];
| |
| | |
| unsigned int newWidth = (double) oldWidth * inputSpacing[0] / spacing;
| |
| unsigned int newHeight = (double) oldHeight * inputSpacing[1] / spacing;
| |
| | |
| // Set the output spacing as specified on the command line
| |
| resizeFilter1->SetOutputSpacing(outputSpacing);
| |
| resizeFilter2->SetOutputSpacing(outputSpacing);
| |
| | |
| // Set the computed size
| |
| itk::Size<2> outputSize = { {newWidth, newHeight} };
| |
| resizeFilter1->SetSize(outputSize);
| |
| resizeFilter2->SetSize(outputSize);
| |
|
| |
| // Specify the input for the resamplers
| |
| resizeFilter1->SetInput(reader->GetOutput());
| |
| resizeFilter2->SetInput(reader->GetOutput());
| |
|
| |
| // Display the images
| |
| typedef itk::ScalarToRGBColormapImageFilter<ImageType, RGBImageType> ColormapFilterType;
| |
| ColormapFilterType::Pointer colormapFilter1 =
| |
| ColormapFilterType::New();
| |
| | |
| ColormapType::Pointer colormap
| |
| = ColormapType::New();
| |
| CreateRandomColormap(4096, colormap);
| |
| | |
| colormapFilter1->SetInput (reader->GetOutput());
| |
| colormapFilter1->SetColormap(colormap);
| |
| | |
| ColormapFilterType::Pointer colormapFilter2 =
| |
| ColormapFilterType::New();
| |
| colormapFilter2->SetInput (resizeFilter1->GetOutput());
| |
| colormapFilter2->SetColormap(colormap);
| |
| | |
| ColormapFilterType::Pointer colormapFilter3 =
| |
| ColormapFilterType::New();
| |
| colormapFilter3->SetInput (resizeFilter2->GetOutput());
| |
| colormapFilter3->SetColormap(colormap);
| |
| | |
| QuickView viewer;
| |
| std::stringstream desc;
| |
| desc << itksys::SystemTools::GetFilenameName(argv[1]) << ": " << oldWidth << ", " << oldHeight;
| |
| viewer.AddRGBImage(
| |
| colormapFilter1->GetOutput(),
| |
| true,
| |
| desc.str());
| |
| | |
| std::stringstream desc2;
| |
| desc2 << "Gaussian Interpolation: " << newWidth << ", " << newHeight;
| |
| viewer.AddRGBImage(
| |
| colormapFilter2->GetOutput(),
| |
| true,
| |
| desc2.str());
| |
| | |
| std::stringstream desc3;
| |
| desc3 << "Nearest Neighbor Interpolation: " << newWidth << ", " << newHeight;
| |
| viewer.AddRGBImage(
| |
| colormapFilter3->GetOutput(),
| |
| true,
| |
| desc3.str());
| |
| | |
| viewer.Visualize();
| |
| | |
| return EXIT_SUCCESS;
| |
| }
| |
| | |
| void CreateRandomColormap(unsigned int size, ColormapType::Pointer colormap)
| |
| {
| |
| #define LOW .3
| |
| ColormapType::ChannelType redChannel;
| |
| ColormapType::ChannelType greenChannel;
| |
| ColormapType::ChannelType blueChannel;
| |
| itk::Statistics::MersenneTwisterRandomVariateGenerator::Pointer random =
| |
| itk::Statistics::MersenneTwisterRandomVariateGenerator::New();
| |
| | |
| random->SetSeed ( 8775070 );
| |
| redChannel.push_back(LOW);
| |
| greenChannel.push_back(LOW);
| |
| blueChannel.push_back(LOW);
| |
| for (unsigned int i = 1; i < size; ++i)
| |
| {
| |
| redChannel.push_back(static_cast<ColormapType::RealType>
| |
| (random->GetUniformVariate(LOW, 1.0)));
| |
| greenChannel.push_back(static_cast<ColormapType::RealType>
| |
| (random->GetUniformVariate(LOW, 1.0)));
| |
| blueChannel.push_back(static_cast<ColormapType::RealType>
| |
| (random->GetUniformVariate(LOW, 1.0)));
| |
| }
| |
| colormap->SetRedChannel(redChannel);
| |
| colormap->SetGreenChannel(greenChannel);
| |
| colormap->SetBlueChannel(blueChannel);
| |
| }
| |
| </source>
| |
| | |
| {{ITKVTKCMakeLists|{{SUBPAGENAME}}}}
| |
