ITK/Examples/Statistics/KdTree

Description

Cluster a collection of measurements using the KMeans algorithm. The name "KdTreeBased" indicates that this is an efficient implementation which uses a KdTree.

KdTree.cxx

<source lang="cpp">

1. include "itkVector.h"
2. include "itkListSample.h"
3. include "itkWeightedCentroidKdTreeGenerator.h"
4. include "itkEuclideanDistanceMetric.h"

int main(int, char *[]) {

 typedef itk::Vector< float, 2 > MeasurementVectorType;

 typedef itk::Statistics::ListSample< MeasurementVectorType > SampleType;
 SampleType::Pointer sample = SampleType::New();
 sample->SetMeasurementVectorSize( 2 );

 MeasurementVectorType mv;
 for (unsigned int i = 0 ; i < 100 ; ++i )
   {
   mv[0] = static_cast<float>(i);
   mv[1] = static_cast<float>(i);
   sample->PushBack( mv );
   }

 typedef itk::Statistics::KdTreeGenerator< SampleType > TreeGeneratorType;
 TreeGeneratorType::Pointer treeGenerator = TreeGeneratorType::New();
 treeGenerator->SetSample( sample );
 treeGenerator->SetBucketSize( 16 );
 treeGenerator->Update();

 typedef TreeGeneratorType::KdTreeType TreeType;
 typedef TreeType::NearestNeighbors NeighborsType;
 typedef TreeType::KdTreeNodeType NodeType;

 TreeType::Pointer tree = treeGenerator->GetOutput();

 MeasurementVectorType queryPoint;
 queryPoint[0] = 10.0;
 queryPoint[1] = 7.0;

 // K-Neighbor search
 std::cout << "K-Neighbor search:" << std::endl;
 unsigned int numberOfNeighbors = 3;
 TreeType::InstanceIdentifierVectorType neighbors;
 tree->Search( queryPoint, numberOfNeighbors, neighbors ) ;

 for ( unsigned int i = 0 ; i < neighbors.size() ; ++i )
   {
   std::cout << tree->GetMeasurementVector( neighbors[i] ) << std::endl;
   }
   
 // Radius search
 std::cout << "Radius search:" << std::endl;
 double radius = 4.0;
 tree->Search( queryPoint, radius, neighbors ) ;
 std::cout << "There are " << neighbors.size() << " neighbors." << std::endl;
 for ( unsigned int i = 0 ; i < neighbors.size() ; ++i )
   {
   std::cout << tree->GetMeasurementVector( neighbors[i] ) << std::endl;
   }

 return EXIT_SUCCESS;

} </source>

CMakeLists.txt

<syntaxhighlight lang="cmake"> cmake_minimum_required(VERSION 3.9.5)

project(KdTreeGenerator)

find_package(ITK REQUIRED) include(${ITK_USE_FILE}) if (ITKVtkGlue_LOADED)

 find_package(VTK REQUIRED)
 include(${VTK_USE_FILE})

else()

 find_package(ItkVtkGlue REQUIRED)
 include(${ItkVtkGlue_USE_FILE})
 set(Glue ItkVtkGlue)

endif()

add_executable(KdTreeGenerator MACOSX_BUNDLE KdTreeGenerator.cxx) target_link_libraries(KdTreeGenerator

 ${Glue}  ${VTK_LIBRARIES} ${ITK_LIBRARIES})

</syntaxhighlight>

Download and Build KdTreeGenerator

Click here to download KdTreeGenerator. and its CMakeLists.txt file. Once the tarball KdTreeGenerator.tar has been downloaded and extracted,

cd KdTreeGenerator/build 

• If ITK is installed:

cmake ..

• If ITK is not installed but compiled on your system, you will need to specify the path to your ITK build:

cmake -DITK_DIR:PATH=/home/me/itk_build ..

Build the project,

make

and run it:

./KdTreeGenerator

WINDOWS USERS PLEASE NOTE: Be sure to add the VTK and ITK bin directories to your path. This will resolve the VTK and ITK dll's at run time.

Building All of the Examples

Many of the examples in the ITK Wiki Examples Collection require VTK. You can build all of the the examples by following these instructions. If you are a new VTK user, you may want to try the Superbuild which will build a proper ITK and VTK.

ItkVtkGlue

ITK >= 4

For examples that use QuickView (which depends on VTK), you must have built ITK with Module_ITKVtkGlue=ON.

ITK < 4

Some of the ITK Examples require VTK to display the images. If you download the entire ITK Wiki Examples Collection, the ItkVtkGlue directory will be included and configured. If you wish to just build a few examples, then you will need to download ItkVtkGlue and build it. When you run cmake it will ask you to specify the location of the ItkVtkGlue binary directory.