GenerateModelsFromLabels
VTKEx/Cxx/Medical/GenerateModelsFromLabels
Description¶
This example uses vtkDiscreteMarchingCubes to create vtkPolyData models from a 3D volume that contains discrete labels. These volumes are normally the output of a segmentation algorithm. The polydata for each label will be output into a separate file.
If you want to see the segmentation results as cube models, see the example GenerateCubesFromLabels. The input volume must be in MetaIO format.
Once you generate the models, you can view them with Paraview
Note
This original source code for this example is here.
Question
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Code¶
GenerateModelsFromLabels.cxx
//
// GenerateModelsFromLabels
// Usage: GenerateModelsFromLabels InputVolume Startlabel Endlabel
// where
// InputVolume is a meta file containing a 3 volume of
// discrete labels.
// StartLabel is the first label to be processed
// EndLabel is the last label to be processed
// NOTE: There can be gaps in the labeling. If a label does
// not exist in the volume, it will be skipped.
//
//
#include <vtkMetaImageReader.h>
#include <vtkImageAccumulate.h>
#include <vtkDiscreteMarchingCubes.h>
#include <vtkWindowedSincPolyDataFilter.h>
#include <vtkMaskFields.h>
#include <vtkThreshold.h>
#include <vtkGeometryFilter.h>
#include <vtkXMLPolyDataWriter.h>
#include <vtkSmartPointer.h>
#include <vtkImageData.h>
#include <vtkPointData.h>
#include <vtkUnstructuredGrid.h>
#include <sstream>
int main (int argc, char *argv[])
{
if (argc < 4)
{
std::cout << "Usage: " << argv[0] << " InputVolume StartLabel EndLabel" << std::endl;
return EXIT_FAILURE;
}
// Create all of the classes we will need
vtkSmartPointer<vtkMetaImageReader> reader =
vtkSmartPointer<vtkMetaImageReader>::New();
vtkSmartPointer<vtkImageAccumulate> histogram =
vtkSmartPointer<vtkImageAccumulate>::New();
vtkSmartPointer<vtkDiscreteMarchingCubes> discreteCubes =
vtkSmartPointer<vtkDiscreteMarchingCubes>::New();
vtkSmartPointer<vtkWindowedSincPolyDataFilter> smoother =
vtkSmartPointer<vtkWindowedSincPolyDataFilter>::New();
vtkSmartPointer<vtkThreshold> selector =
vtkSmartPointer<vtkThreshold>::New();
vtkSmartPointer<vtkMaskFields> scalarsOff =
vtkSmartPointer<vtkMaskFields>::New();
vtkSmartPointer<vtkGeometryFilter> geometry =
vtkSmartPointer<vtkGeometryFilter>::New();
vtkSmartPointer<vtkXMLPolyDataWriter> writer =
vtkSmartPointer<vtkXMLPolyDataWriter>::New();
// Define all of the variables
unsigned int startLabel = atoi(argv[2]);
unsigned int endLabel = atoi(argv[3]);
std::string filePrefix = "Label";
unsigned int smoothingIterations = 15;
double passBand = 0.001;
double featureAngle = 120.0;
// Generate models from labels
// 1) Read the meta file
// 2) Generate a histogram of the labels
// 3) Generate models from the labeled volume
// 4) Smooth the models
// 5) Output each model into a separate file
reader->SetFileName(argv[1]);
histogram->SetInputConnection(reader->GetOutputPort());
histogram->SetComponentExtent(0, endLabel, 0, 0, 0, 0);
histogram->SetComponentOrigin(0, 0, 0);
histogram->SetComponentSpacing(1, 1, 1);
histogram->Update();
discreteCubes->SetInputConnection(reader->GetOutputPort());
discreteCubes->GenerateValues(
endLabel - startLabel + 1, startLabel, endLabel);
smoother->SetInputConnection(discreteCubes->GetOutputPort());
smoother->SetNumberOfIterations(smoothingIterations);
smoother->BoundarySmoothingOff();
smoother->FeatureEdgeSmoothingOff();
smoother->SetFeatureAngle(featureAngle);
smoother->SetPassBand(passBand);
smoother->NonManifoldSmoothingOn();
smoother->NormalizeCoordinatesOn();
smoother->Update();
selector->SetInputConnection(smoother->GetOutputPort());
selector->SetInputArrayToProcess(0, 0, 0,
vtkDataObject::FIELD_ASSOCIATION_CELLS,
vtkDataSetAttributes::SCALARS);
// Strip the scalars from the output
scalarsOff->SetInputConnection(selector->GetOutputPort());
scalarsOff->CopyAttributeOff(vtkMaskFields::POINT_DATA,
vtkDataSetAttributes::SCALARS);
scalarsOff->CopyAttributeOff(vtkMaskFields::CELL_DATA,
vtkDataSetAttributes::SCALARS);
geometry->SetInputConnection(scalarsOff->GetOutputPort());
writer->SetInputConnection(geometry->GetOutputPort());
for (unsigned int i = startLabel; i <= endLabel; i++)
{
// see if the label exists, if not skip it
double frequency =
histogram->GetOutput()->GetPointData()->GetScalars()->GetTuple1(i);
if (frequency == 0.0)
{
continue;
}
// select the cells for a given label
selector->ThresholdBetween(i, i);
// output the polydata
std::stringstream ss;
ss << filePrefix << i << ".vtp";
std::cout << argv[0] << " writing " << ss.str() << std::endl;
writer->SetFileName(ss.str().c_str());
writer->Write();
}
return EXIT_SUCCESS;
}
CMakeLists.txt¶
cmake_minimum_required(VERSION 3.3 FATAL_ERROR)
project(GenerateModelsFromLabels)
find_package(VTK COMPONENTS
vtkvtkCommonCore
vtkvtkCommonDataModel
vtkvtkFiltersCore
vtkvtkFiltersGeneral
vtkvtkFiltersGeometry
vtkvtkIOImage
vtkvtkIOXML
vtkvtkImagingStatistics QUIET)
if (NOT VTK_FOUND)
message("Skipping GenerateModelsFromLabels: ${VTK_NOT_FOUND_MESSAGE}")
return ()
endif()
message (STATUS "VTK_VERSION: ${VTK_VERSION}")
if (VTK_VERSION VERSION_LESS "8.90.0")
# old system
include(${VTK_USE_FILE})
add_executable(GenerateModelsFromLabels MACOSX_BUNDLE GenerateModelsFromLabels.cxx )
target_link_libraries(GenerateModelsFromLabels PRIVATE ${VTK_LIBRARIES})
else ()
# include all components
add_executable(GenerateModelsFromLabels MACOSX_BUNDLE GenerateModelsFromLabels.cxx )
target_link_libraries(GenerateModelsFromLabels PRIVATE ${VTK_LIBRARIES})
# vtk_module_autoinit is needed
vtk_module_autoinit(
TARGETS GenerateModelsFromLabels
MODULES ${VTK_LIBRARIES}
)
endif ()
Download and Build GenerateModelsFromLabels¶
Click here to download GenerateModelsFromLabels and its CMakeLists.txt file. Once the tarball GenerateModelsFromLabels.tar has been downloaded and extracted,
cd GenerateModelsFromLabels/build
If VTK is installed:
cmake ..
If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:
cmake -DVTK_DIR:PATH=/home/me/vtk_build ..
Build the project:
make
and run it:
./GenerateModelsFromLabels
WINDOWS USERS
Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.