LandmarkTransform

VTKEx/Cxx/Filtering/LandmarkTransform

Description

This example creates two point sets which it assumes are known, ordered correspondences. It then transforms Source to Target and displays the matrix used in the transformation.

Question

If you have a simple question about this example contact us at VTKExProject If your question is more complex and may require extended discussion, please use the VTK Discourse Forum

Code

LandmarkTransform.cxx

#include <vtkPoints.h>
#include <vtkSmartPointer.h>
#include <vtkLandmarkTransform.h>
#include <vtkMatrix4x4.h>
#include <vtkPolyDataMapper.h>
#include <vtkActor.h>
#include <vtkRenderWindow.h>
#include <vtkRenderer.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkProperty.h>
#include <vtkTransformPolyDataFilter.h>
#include <vtkVertexGlyphFilter.h>

int main(int, char *[])
{
  /*
  This demo creates a coordinate frame (+x, +y, +z) of vectors and a rotated,
  peturbed frame (+z, +y, -x) and aligns the rotated frame to the original as best as possible.
  */

  vtkSmartPointer<vtkPoints> sourcePoints =
    vtkSmartPointer<vtkPoints>::New();
  double sourcePoint1[3] = {1.0, 0.0, 0.0};
  sourcePoints->InsertNextPoint(sourcePoint1);
  double sourcePoint2[3] = {0.0, 1.0, 0.0};
  sourcePoints->InsertNextPoint(sourcePoint2);
  double sourcePoint3[3] = {0.0, 0.0, 1.0};
  sourcePoints->InsertNextPoint(sourcePoint3);

  vtkSmartPointer<vtkPoints> targetPoints =
    vtkSmartPointer<vtkPoints>::New();
  double targetPoint1[3] = {0.0, 0.0, 1.1};
  targetPoints->InsertNextPoint(targetPoint1);
  double targetPoint2[3] = {0.0, 1.02, 0.0};
  targetPoints->InsertNextPoint(targetPoint2);
  double targetPoint3[3] = {-1.11, 0.0, 0.0};
  targetPoints->InsertNextPoint(targetPoint3);

  // Setup the transform
  vtkSmartPointer<vtkLandmarkTransform> landmarkTransform = 
    vtkSmartPointer<vtkLandmarkTransform>::New();
  landmarkTransform->SetSourceLandmarks(sourcePoints);
  landmarkTransform->SetTargetLandmarks(targetPoints);
  landmarkTransform->SetModeToRigidBody();
  landmarkTransform->Update(); //should this be here?

  vtkSmartPointer<vtkPolyData> source =
    vtkSmartPointer<vtkPolyData>::New();
  source->SetPoints(sourcePoints);

  vtkSmartPointer<vtkPolyData> target =
    vtkSmartPointer<vtkPolyData>::New();
  target->SetPoints(targetPoints);

  vtkSmartPointer<vtkVertexGlyphFilter> sourceGlyphFilter =
    vtkSmartPointer<vtkVertexGlyphFilter>::New();
  sourceGlyphFilter->SetInputData(source);
  sourceGlyphFilter->Update();

  vtkSmartPointer<vtkVertexGlyphFilter> targetGlyphFilter =
    vtkSmartPointer<vtkVertexGlyphFilter>::New();
  targetGlyphFilter->SetInputData(target);
  targetGlyphFilter->Update();

  vtkSmartPointer<vtkTransformPolyDataFilter> transformFilter =
    vtkSmartPointer<vtkTransformPolyDataFilter>::New();
  transformFilter->SetInputConnection(sourceGlyphFilter->GetOutputPort());
  transformFilter->SetTransform(landmarkTransform);
  transformFilter->Update();

  // Display the transformation matrix that was computed
  vtkMatrix4x4* mat = landmarkTransform->GetMatrix();
  std::cout << "Matrix: " << *mat << std::endl;

  // Visualize
  vtkSmartPointer<vtkPolyDataMapper> sourceMapper =
    vtkSmartPointer<vtkPolyDataMapper>::New();
  sourceMapper->SetInputConnection(sourceGlyphFilter->GetOutputPort());

  vtkSmartPointer<vtkActor> sourceActor =
    vtkSmartPointer<vtkActor>::New();
  sourceActor->SetMapper(sourceMapper);
  sourceActor->GetProperty()->SetColor(0,1,0);
  sourceActor->GetProperty()->SetPointSize(4);

  vtkSmartPointer<vtkPolyDataMapper> targetMapper =
    vtkSmartPointer<vtkPolyDataMapper>::New();
  targetMapper->SetInputConnection(targetGlyphFilter->GetOutputPort());

  vtkSmartPointer<vtkActor> targetActor =
    vtkSmartPointer<vtkActor>::New();
  targetActor->SetMapper(targetMapper);
  targetActor->GetProperty()->SetColor(1,0,0);
  targetActor->GetProperty()->SetPointSize(4);

  vtkSmartPointer<vtkPolyDataMapper> solutionMapper =
    vtkSmartPointer<vtkPolyDataMapper>::New();
  solutionMapper->SetInputConnection(transformFilter->GetOutputPort());

  vtkSmartPointer<vtkActor> solutionActor =
    vtkSmartPointer<vtkActor>::New();
  solutionActor->SetMapper(solutionMapper);
  solutionActor->GetProperty()->SetColor(0,0,1);
  solutionActor->GetProperty()->SetPointSize(3);

  // Create a renderer, render window, and interactor
  vtkSmartPointer<vtkRenderer> renderer =
    vtkSmartPointer<vtkRenderer>::New();
  vtkSmartPointer<vtkRenderWindow> renderWindow =
    vtkSmartPointer<vtkRenderWindow>::New();
  renderWindow->AddRenderer(renderer);
  vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
    vtkSmartPointer<vtkRenderWindowInteractor>::New();
  renderWindowInteractor->SetRenderWindow(renderWindow);

  // Add the actor to the scene
  renderer->AddActor(sourceActor);
  renderer->AddActor(targetActor);
  renderer->AddActor(solutionActor);
  renderer->SetBackground(.3, .6, .3); // Background color green

  // Render and interact
  renderWindow->Render();
  renderWindowInteractor->Start();

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(LandmarkTransform)

find_package(VTK COMPONENTS 
  vtkvtkCommonCore
  vtkvtkCommonMath
  vtkvtkCommonTransforms
  vtkvtkFiltersGeneral
  vtkvtkInteractionStyle
  vtkvtkRenderingContextOpenGL2
  vtkvtkRenderingCore
  vtkvtkRenderingFreeType
  vtkvtkRenderingGL2PSOpenGL2
  vtkvtkRenderingOpenGL2 QUIET)
if (NOT VTK_FOUND)
  message("Skipping LandmarkTransform: ${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(LandmarkTransform MACOSX_BUNDLE LandmarkTransform.cxx )
  target_link_libraries(LandmarkTransform PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(LandmarkTransform MACOSX_BUNDLE LandmarkTransform.cxx )
  target_link_libraries(LandmarkTransform PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS LandmarkTransform
    MODULES ${VTK_LIBRARIES}
    )
endif ()

Download and Build LandmarkTransform

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

cd LandmarkTransform/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:

./LandmarkTransform

WINDOWS USERS

Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.