ITK  5.2.0
Insight Toolkit
Examples/Filtering/ResampleImageFilter4.cxx
/*=========================================================================
*
* Copyright NumFOCUS
*
* 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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*=========================================================================*/
// Software Guide : BeginCommandLineArgs
// INPUTS: {BrainProtonDensitySlice.png}
// OUTPUTS: {ResampleImageFilterOutput10.png}
// ARGUMENTS: -15
// Software Guide : EndCommandLineArgs
// Software Guide : BeginLatex
//
// The following example illustrates how to rotate an image around its
// center. In this particular case an \doxygen{AffineTransform} is used to
// map the input space into the output space.
//
// \index{itk::AffineTransform!resampling}
//
// Software Guide : EndLatex
#include "itkImage.h"
// Software Guide : BeginLatex
//
// The header of the affine transform is included below.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
// Software Guide : EndCodeSnippet
int
main(int argc, char * argv[])
{
if (argc < 4)
{
std::cerr << "Usage: " << std::endl;
std::cerr << argv[0] << " inputImageFile outputImageFile degrees"
<< std::endl;
return EXIT_FAILURE;
}
constexpr unsigned int Dimension = 2;
using InputPixelType = unsigned char;
using OutputPixelType = unsigned char;
using InputImageType = itk::Image<InputPixelType, Dimension>;
using OutputImageType = itk::Image<OutputPixelType, Dimension>;
ReaderType::Pointer reader = ReaderType::New();
WriterType::Pointer writer = WriterType::New();
reader->SetFileName(argv[1]);
writer->SetFileName(argv[2]);
const double angleInDegrees = std::stod(argv[3]);
using FilterType =
FilterType::Pointer filter = FilterType::New();
// Software Guide : BeginLatex
//
// The transform type is instantiated using the coordinate representation
// type and the space dimension. Then a transform object is constructed
// with the \code{New()} method and passed to a \doxygen{SmartPointer}.
//
// \index{itk::AffineTransform!instantiation}
// \index{itk::AffineTransform!New()}
// \index{itk::AffineTransform!Pointer}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
TransformType::Pointer transform = TransformType::New();
// Software Guide : EndCodeSnippet
using InterpolatorType =
InterpolatorType::Pointer interpolator = InterpolatorType::New();
filter->SetInterpolator(interpolator);
filter->SetDefaultPixelValue(100);
// Software Guide : BeginLatex
//
// The parameters of the output image are taken from the input image.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
reader->Update();
const InputImageType * inputImage = reader->GetOutput();
const InputImageType::SpacingType & spacing = inputImage->GetSpacing();
const InputImageType::PointType & origin = inputImage->GetOrigin();
inputImage->GetLargestPossibleRegion().GetSize();
filter->SetOutputOrigin(origin);
filter->SetOutputSpacing(spacing);
filter->SetOutputDirection(inputImage->GetDirection());
filter->SetSize(size);
// Software Guide : EndCodeSnippet
filter->SetInput(reader->GetOutput());
writer->SetInput(filter->GetOutput());
// Software Guide : BeginLatex
//
// Rotations are performed around the origin of physical coordinates---not
// the image origin nor the image center. Hence, the process of
// positioning the output image frame as it is shown in Figure
// \ref{fig:ResampleImageFilterOutput10} requires three steps. First, the
// image origin must be moved to the origin of the coordinate system. This
// is done by applying a translation equal to the negative values of the
// image origin.
//
// \begin{figure}
// \center
// \includegraphics[width=0.44\textwidth]{BrainProtonDensitySliceBorder20}
// \includegraphics[width=0.44\textwidth]{ResampleImageFilterOutput10}
// \itkcaption[Effect of the Resample filter rotating an image]{Effect of
// the resample filter rotating an image.}
// \label{fig:ResampleImageFilterOutput10}
// \end{figure}
//
//
// \index{itk::AffineTransform!Translate()}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
TransformType::OutputVectorType translation1;
const double imageCenterX = origin[0] + spacing[0] * size[0] / 2.0;
const double imageCenterY = origin[1] + spacing[1] * size[1] / 2.0;
translation1[0] = -imageCenterX;
translation1[1] = -imageCenterY;
transform->Translate(translation1);
// Software Guide : EndCodeSnippet
std::cout << "imageCenterX = " << imageCenterX << std::endl;
std::cout << "imageCenterY = " << imageCenterY << std::endl;
// Software Guide : BeginLatex
//
// In a second step, the rotation is specified using the method
// \code{Rotate2D()}.
//
// \index{itk::AffineTransform!Rotate2D()}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
const double degreesToRadians = std::atan(1.0) / 45.0;
const double angle = angleInDegrees * degreesToRadians;
transform->Rotate2D(-angle, false);
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The third and final step requires translating the image origin back to
// its previous location. This is be done by applying a translation equal
// to the origin values.
//
// \index{itk::AffineTransform!Translate()}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
TransformType::OutputVectorType translation2;
translation2[0] = imageCenterX;
translation2[1] = imageCenterY;
transform->Translate(translation2, false);
filter->SetTransform(transform);
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The output of the resampling filter is connected to a writer and the
// execution of the pipeline is triggered by a writer update.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
try
{
writer->Update();
}
catch (const itk::ExceptionObject & excep)
{
std::cerr << "Exception caught !" << std::endl;
std::cerr << excep << std::endl;
}
// Software Guide : EndCodeSnippet
return EXIT_SUCCESS;
}
itk::GTest::TypedefsAndConstructors::Dimension2::PointType
ImageBaseType::PointType PointType
Definition: itkGTestTypedefsAndConstructors.h:51
itkImageFileReader.h
itk::GTest::TypedefsAndConstructors::Dimension2::SizeType
ImageBaseType::SizeType SizeType
Definition: itkGTestTypedefsAndConstructors.h:49
itkImage.h
itkAffineTransform.h
itk::AffineTransform
Definition: itkAffineTransform.h:101
itk::ImageFileReader
Data source that reads image data from a single file.
Definition: itkImageFileReader.h:75
itk::LinearInterpolateImageFunction
Linearly interpolate an image at specified positions.
Definition: itkLinearInterpolateImageFunction.h:50
itk::ImageFileWriter
Writes image data to a single file.
Definition: itkImageFileWriter.h:87
itkImageFileWriter.h
itk::ResampleImageFilter
Resample an image via a coordinate transform.
Definition: itkResampleImageFilter.h:90
itk::Image
Templated n-dimensional image class.
Definition: itkImage.h:86
itkResampleImageFilter.h
itk::GTest::TypedefsAndConstructors::Dimension2::Dimension
constexpr unsigned int Dimension
Definition: itkGTestTypedefsAndConstructors.h:44
itk::Size::GetSize
const SizeValueType * GetSize() const
Definition: itkSize.h:169