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| In this example, we demonstrate the itkScaleTransform. By specifying the scale as 1.5, what we are actually doing is making the new image bigger than the old image in the physical space. When the image is resampled, the outer regions of the image are not overlapping the old image. Therefore, the resulting image appears to have shrunk, even though the scale factor was > 1.
| | {{warning|1=The media wiki content on this page is no longer maintained.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. |
| | }} |
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| ==ScaleTransform.cxx==
| | [https://itk.org/ITKExamples[ITK Sphinx Examples]] |
| <source lang="cpp">
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| #include "itkImage.h"
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| #include "itkScaleTransform.h"
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| #include "itkImageFileReader.h"
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| #include "itkImageFileWriter.h"
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| #include "itkResampleImageFilter.h"
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| | |
| typedef itk::Image<unsigned char, 2> ImageType;
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| | |
| static void CreateImage(ImageType::Pointer image);
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| | |
| int main(int argc, char *argv[])
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| {
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| ImageType::Pointer image = ImageType::New();
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| CreateImage(image);
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|
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| typedef itk::ImageFileWriter<ImageType> WriterType;
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| WriterType::Pointer inputWriter = WriterType::New();
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| inputWriter->SetFileName("input.png");
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| inputWriter->SetInput(image);
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| inputWriter->Update();
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| | |
| // typedef itk::ScaleTransform<float, 2> TransformType; // If you want to use float here, you must use:
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| // typedef itk::ResampleImageFilter<ImageType, ImageType, float> ResampleImageFilterType; later.
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| typedef itk::ScaleTransform<double, 2> TransformType;
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| TransformType::Pointer scaleTransform = TransformType::New();
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| itk::FixedArray<float, 2> scale;
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| scale[0] = 1.5; // newWidth/oldWidth
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| scale[1] = 1.5;
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| scaleTransform->SetScale(scale);
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| | |
| itk::Point<float,2> center;
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| center[0] = image->GetLargestPossibleRegion().GetSize()[0]/2;
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| center[1] = image->GetLargestPossibleRegion().GetSize()[1]/2;
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| | |
| scaleTransform->SetCenter(center);
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|
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| typedef itk::ResampleImageFilter<ImageType, ImageType> ResampleImageFilterType;
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| ResampleImageFilterType::Pointer resampleFilter = ResampleImageFilterType::New();
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| resampleFilter->SetTransform(scaleTransform);
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| resampleFilter->SetInput(image);
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| resampleFilter->SetSize(image->GetLargestPossibleRegion().GetSize());
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| resampleFilter->Update();
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| | |
| WriterType::Pointer outputWriter = WriterType::New();
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| outputWriter->SetFileName("output.png");
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| outputWriter->SetInput(resampleFilter->GetOutput());
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| outputWriter->Update();
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| | |
| return EXIT_SUCCESS;
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| }
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| | |
| void CreateImage(ImageType::Pointer image)
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| {
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| itk::Index<2> start;
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| start.Fill(0);
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| itk::Size<2> size;
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| size.Fill(101);
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| ImageType::RegionType region(start, size);
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| image->SetRegions(region);
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| image->Allocate();
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| image->FillBuffer(0);
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| | |
| // Make a white square
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| for(unsigned int r = 40; r < 60; r++)
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| {
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| for(unsigned int c = 40; c < 60; c++)
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| {
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| ImageType::IndexType pixelIndex;
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| pixelIndex[0] = r;
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| pixelIndex[1] = c;
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| | |
| image->SetPixel(pixelIndex, 255);
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| }
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| }
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| | |
| itk::ImageRegionIterator<ImageType> imageIterator(image, image->GetLargestPossibleRegion());
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| | |
| // Draw a white border
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| while(!imageIterator.IsAtEnd())
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| {
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| if(imageIterator.GetIndex()[0] == 0 || imageIterator.GetIndex()[0] == static_cast<int>(image->GetLargestPossibleRegion().GetSize()[0]) - 1 ||
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| imageIterator.GetIndex()[1] == 0 || imageIterator.GetIndex()[1] == static_cast<int>(image->GetLargestPossibleRegion().GetSize()[1]) - 1)
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| {
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| imageIterator.Set(255);
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| }
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| ++imageIterator;
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| }
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| }
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| | |
| </source>
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| | |
| {{ITKCMakeLists|ScaleTransform}}
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