ITK  5.2.0
Insight Toolkit
Examples/Segmentation/RelabelComponentImageFilter.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.
*
*=========================================================================*/
// Software Guide : BeginLatex
//
// The \doxygen{RelabelComponentImageFilter} is commonly used for
// reorganizing the labels in an image that has been produced as the result
// of a segmentation method. For example, region growing, or a K-means
// statistical classification.
//
// \index{itk::RelabelComponentImageFilter}
//
// Software Guide : EndLatex
// Software Guide : BeginLatex
//
// The header file corresponding to this filter should be included first.
//
// \index{itk::RelabelComponentImageFilter!header}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
// Software Guide : EndCodeSnippet
int
main(int argc, char * argv[])
{
if (argc < 3)
{
std::cerr << "Usage: " << std::endl;
std::cerr << argv[0] << " inputImageFile outputImageFile" << std::endl;
return EXIT_FAILURE;
}
// Software Guide : BeginLatex
//
// Then the pixel types for input and output image must be defined and,
// with them, the image types can be instantiated.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
using InputPixelType = unsigned char;
using OutputPixelType = unsigned char;
using InputImageType = itk::Image<InputPixelType, 2>;
using OutputImageType = itk::Image<OutputPixelType, 2>;
// Software Guide : EndCodeSnippet
ReaderType::Pointer reader = ReaderType::New();
WriterType::Pointer writer = WriterType::New();
reader->SetFileName(argv[1]);
writer->SetFileName(argv[2]);
// Software Guide : BeginLatex
//
// Using the image types it is now possible to instantiate the filter type
// and create the filter object.
//
// \index{itk::RelabelComponentImageFilter!instantiation}
// \index{itk::RelabelComponentImageFilter!New()}
// \index{itk::RelabelComponentImageFilter!Pointer}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
using FilterType =
FilterType::Pointer relabeler = FilterType::New();
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The input to the filter can be taken from any other filter, for example
// a reader. The output can be passed down the pipeline to other filters,
// for example, a writer. An update call on any downstream filter will
// trigger the execution of the mean filter.
//
// \index{itk::RelabelComponentImageFilter!SetInput()}
// \index{itk::RelabelComponentImageFilter!GetOutput()}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
relabeler->SetInput(reader->GetOutput());
writer->SetInput(relabeler->GetOutput());
writer->Update();
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// We can now query the size of each one of the connected components, both
// in pixel units and in physical units.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
using SizesInPixelsType = std::vector<itk::SizeValueType>;
const SizesInPixelsType & sizesInPixels =
relabeler->GetSizeOfObjectsInPixels();
auto sizeItr = sizesInPixels.begin();
auto sizeEnd = sizesInPixels.end();
std::cout << "Number of pixels per class " << std::endl;
unsigned int kclass = 0;
while (sizeItr != sizeEnd)
{
std::cout << "Class " << kclass << " = " << *sizeItr << std::endl;
++kclass;
++sizeItr;
}
// Software Guide : EndCodeSnippet
// Software Guide : BeginCodeSnippet
using SizesInPhysicalUnitsType = std::vector<float>;
const SizesInPhysicalUnitsType sizesInUnits =
relabeler->GetSizeOfObjectsInPhysicalUnits();
auto physicalSizeItr = sizesInUnits.begin();
auto physicalSizeEnd = sizesInUnits.end();
std::cout << "Area in Physical Units per class " << std::endl;
unsigned int jclass = 0;
while (physicalSizeItr != physicalSizeEnd)
{
std::cout << "Class " << jclass << " = " << *physicalSizeItr << std::endl;
++jclass;
++physicalSizeItr;
}
// Software Guide : EndCodeSnippet
return EXIT_SUCCESS;
}
itkImageFileReader.h
itkRelabelComponentImageFilter.h
itk::ImageFileReader
Data source that reads image data from a single file.
Definition: itkImageFileReader.h:75
itk::ImageFileWriter
Writes image data to a single file.
Definition: itkImageFileWriter.h:87
itkImageFileWriter.h
itk::RelabelComponentImageFilter
Relabel the components in an image such that consecutive labels are used.
Definition: itkRelabelComponentImageFilter.h:82
itk::Image
Templated n-dimensional image class.
Definition: itkImage.h:86