ITK  5.2.0
Insight Toolkit
SphinxExamples/src/Filtering/LabelMap/RemoveLabelsFromLabelMap/Code.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.
*
*=========================================================================*/
#include "itkImage.h"
using ImageType = itk::Image<unsigned char, 2>;
static void
CreateImage(ImageType::Pointer image);
int
main(int, char *[])
{
ImageType::Pointer image = ImageType::New();
CreateImage(image);
using BinaryImageToLabelMapFilterType = itk::BinaryImageToLabelMapFilter<ImageType>;
BinaryImageToLabelMapFilterType::Pointer binaryImageToLabelMapFilter = BinaryImageToLabelMapFilterType::New();
binaryImageToLabelMapFilter->SetInput(image);
binaryImageToLabelMapFilter->Update();
// The output of this filter is an itk::LabelMap, which contains itk::LabelObject's
std::cout << "There are " << binaryImageToLabelMapFilter->GetOutput()->GetNumberOfLabelObjects() << " objects."
<< std::endl;
std::vector<unsigned long> labelsToRemove;
std::cout << "There are originally " << binaryImageToLabelMapFilter->GetOutput()->GetNumberOfLabelObjects()
<< " objects." << std::endl;
// Note: do NOT remove the labels inside the loop! The IDs are stored such that they will change when one is deleted.
// Instead, mark all of the labels to be removed first and then remove them all together.
for (unsigned int i = 0; i < binaryImageToLabelMapFilter->GetOutput()->GetNumberOfLabelObjects(); i++)
{
// Get the ith region
BinaryImageToLabelMapFilterType::OutputImageType::LabelObjectType * labelObject =
binaryImageToLabelMapFilter->GetOutput()->GetNthLabelObject(i);
// std::cout << "Region " << i << " has " << labelObject->Size() << " pixels." << std::endl;
// Mark every other label to be removed
if (i % 2 == 0)
{
labelsToRemove.push_back(labelObject->GetLabel());
}
}
std::cout << "Removing " << labelsToRemove.size() << " objects." << std::endl;
// Remove all regions that were marked for removal.
for (unsigned long i : labelsToRemove)
{
binaryImageToLabelMapFilter->GetOutput()->RemoveLabel(i);
}
std::cout << "There are " << binaryImageToLabelMapFilter->GetOutput()->GetNumberOfLabelObjects()
<< " objects remaining." << std::endl;
return EXIT_SUCCESS;
}
void
CreateImage(ImageType::Pointer image)
{
// Create a black image with a white square
start.Fill(0);
size.Fill(20);
ImageType::RegionType region(start, size);
image->SetRegions(region);
image->Allocate();
image->FillBuffer(0);
// Make line of non-touching diagonal pixels
for (unsigned int i = 0; i < 20; i += 2)
{
pixel[0] = i;
pixel[1] = i;
image->SetPixel(pixel, 255);
}
}
itk::Index
Represent a n-dimensional index in a n-dimensional image.
Definition: itkIndex.h:66
itk::GTest::TypedefsAndConstructors::Dimension2::SizeType
ImageBaseType::SizeType SizeType
Definition: itkGTestTypedefsAndConstructors.h:49
itkImage.h
itkImageRegionIterator.h
itk::Index::Fill
void Fill(IndexValueType value)
Definition: itkIndex.h:270
itk::BinaryImageToLabelMapFilter
Label the connected components in a binary image and produce a collection of label objects.
Definition: itkBinaryImageToLabelMapFilter.h:56
itk::Size::Fill
void Fill(SizeValueType value)
Definition: itkSize.h:211
itk::GTest::TypedefsAndConstructors::Dimension2::IndexType
ImageBaseType::IndexType IndexType
Definition: itkGTestTypedefsAndConstructors.h:50
itk::GTest::TypedefsAndConstructors::Dimension2::RegionType
ImageBaseType::RegionType RegionType
Definition: itkGTestTypedefsAndConstructors.h:54
itkBinaryImageToLabelMapFilter.h
itkImageFileWriter.h
itk::Image
Templated n-dimensional image class.
Definition: itkImage.h:86