LandmarkTransform
VTKExamples/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.
Code
LandmarkTransform.cxx
#include <vtkVersion.h>
#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();
#if VTK_MAJOR_VERSION <= 5
sourceGlyphFilter->SetInputConnection(source->GetProducerPort());
#else
sourceGlyphFilter->SetInputData(source);
#endif
sourceGlyphFilter->Update();
vtkSmartPointer<vtkVertexGlyphFilter> targetGlyphFilter =
vtkSmartPointer<vtkVertexGlyphFilter>::New();
#if VTK_MAJOR_VERSION <= 5
targetGlyphFilter->SetInputConnection(target->GetProducerPort());
#else
targetGlyphFilter->SetInputData(target);
#endif
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 2.8)
PROJECT(LandmarkTransform)
find_package(VTK REQUIRED)
include(${VTK_USE_FILE})
add_executable(LandmarkTransform MACOSX_BUNDLE LandmarkTransform.cxx)
target_link_libraries(LandmarkTransform ${VTK_LIBRARIES})
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 PLEASE NOTE: Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.