CurvedReformation

VTKExamples/Cxx/Visualization/CurvedReformation


Description

This example makes a curved reformation of a volume. The example requires three parameters:

  1. Input volume

  2. Input polydata that defines a polyline for the reformation. The polyline will be resampled with a cubic spline

  3. Resolution is the result resolution of the reformation.

Code

CurvedReformation.cxx

#include <vtkVersion.h>
#include <vtkSmartPointer.h>

#include <vtkImageReader2Factory.h>
#include <vtkImageReader2.h>
#include <vtkPolyDataReader.h>
#include <vtkProbeFilter.h>
#include <vtkImageData.h>
#include <vtkSplineFilter.h>

#include <vtkPoints.h>
#include <vtkCellArray.h>
#include <vtkPolyData.h>

#include <vtkWindowLevelLookupTable.h>
#include <vtkDataSetMapper.h>
#include <vtkActor.h>
#include <vtkCamera.h>
#include <vtkRenderWindow.h>
#include <vtkRenderer.h>
#include <vtkRenderWindowInteractor.h>

#include <sstream>

static vtkSmartPointer<vtkPolyData> SweepLine (vtkPolyData *line,
                                               double direction[3],
                                               double distance,
                                               unsigned int cols);
int main (int argc, char *argv[])
{
  // Verify arguments
  if (argc < 4)
  {
      std::cout << "Usage: " << argv[0]
                << " InputVolume PolyDataInput"
                << " Resolution"
                << std::endl;
      return EXIT_FAILURE;
  }

  // Parse arguments
  std::string volumeFileName = argv[1];
  std::string polyDataFileName = argv[2];
  std::stringstream ssResolution;
  ssResolution << argv[3];
  unsigned int resolution;
  ssResolution >> resolution;

  // Output arguments
  std::cout << "InputVolume: " << volumeFileName << std::endl
            << "PolyDataInput: " << polyDataFileName << std::endl
            << "Resolution: " << resolution << std::endl;

  // Read the volume data
  vtkSmartPointer< vtkImageReader2Factory > imageFactory =
    vtkSmartPointer< vtkImageReader2Factory >::New();
  vtkImageReader2 *imageReader =
  imageFactory->CreateImageReader2(volumeFileName.c_str());
  imageReader->SetFileName(volumeFileName.c_str());
  imageReader->Update();

  // Read the Polyline
  vtkSmartPointer<vtkPolyDataReader> polyLineReader =
    vtkSmartPointer<vtkPolyDataReader>::New();
  polyLineReader->SetFileName(polyDataFileName.c_str());
  polyLineReader->Update();

  vtkSmartPointer<vtkSplineFilter> spline =
    vtkSmartPointer<vtkSplineFilter>::New();
  spline->SetInputConnection(polyLineReader->GetOutputPort());
  spline->SetSubdivideToSpecified();
  spline->SetNumberOfSubdivisions(resolution);

  // Sweep the line to form a surface
  double direction[3];
  direction[0] = 0.0;
  direction[1] = 0.0;
  direction[2] = 1.0;
  double distance = 164;
  spline->Update();
  vtkSmartPointer<vtkPolyData> surface =
    SweepLine(spline->GetOutput(),
              direction,
              distance,
              atoi(argv[3]));

  // Probe the volume with the extruded surface
  vtkSmartPointer<vtkProbeFilter> sampleVolume =
    vtkSmartPointer<vtkProbeFilter>::New();
  sampleVolume->SetInputConnection(1, imageReader->GetOutputPort());
#if VTK_MAJOR_VERSION <= 5
  sampleVolume->SetInput(0, surface);
 #else
  sampleVolume->SetInputData(0, surface);
#endif
  // Compute a simple window/level based on scalar range
  vtkSmartPointer<vtkWindowLevelLookupTable> wlLut =
    vtkSmartPointer<vtkWindowLevelLookupTable>::New();
  double range = imageReader->GetOutput()->GetScalarRange()[1] -
                 imageReader->GetOutput()->GetScalarRange()[0];
  double level = (imageReader->GetOutput()->GetScalarRange()[1] +
                  imageReader->GetOutput()->GetScalarRange()[0]) / 2.0;
  wlLut->SetWindow(range);
  wlLut->SetLevel(level);

  // Create a mapper and actor.
  vtkSmartPointer<vtkDataSetMapper> mapper =
    vtkSmartPointer<vtkDataSetMapper>::New();
  mapper->SetInputConnection(sampleVolume->GetOutputPort());
  mapper->SetLookupTable(wlLut);
  mapper->SetScalarRange(0, 255);

  vtkSmartPointer<vtkActor> actor =
    vtkSmartPointer<vtkActor>::New();
  actor->SetMapper(mapper);

  // 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 actors to the scene
  renderer->AddActor(actor);
  renderer->SetBackground(.2, .3, .4);

  // Set the camera for viewing medical images
  renderer->GetActiveCamera()->SetViewUp(0,0,1);
  renderer->GetActiveCamera()->SetPosition(0,0,0);
  renderer->GetActiveCamera()->SetFocalPoint(0,1,0);
  renderer->ResetCamera();

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

  imageReader->Delete();
  return EXIT_SUCCESS;
}

vtkSmartPointer<vtkPolyData> SweepLine (vtkPolyData *line,
                                        double direction[3],
                                        double distance,
                                        unsigned int cols)
{
  unsigned int rows = line->GetNumberOfPoints();
  double spacing = distance / cols;
  vtkSmartPointer<vtkPolyData> surface =
    vtkSmartPointer<vtkPolyData>::New();

  // Generate the points
  cols++;
  unsigned int numberOfPoints = rows * cols;
  unsigned int numberOfPolys = (rows - 1) * (cols - 1);
  vtkSmartPointer<vtkPoints> points =
    vtkSmartPointer<vtkPoints>::New();
  points->Allocate(numberOfPoints);
  vtkSmartPointer<vtkCellArray> polys =
    vtkSmartPointer<vtkCellArray>::New();
  polys->Allocate(numberOfPolys*4);

  double x[3];
  unsigned int cnt = 0;
  for (unsigned int row = 0; row < rows; row++)
  {
      for (unsigned int col = 0; col < cols; col++)
      {
          double p[3];
          line->GetPoint(row, p);
          x[0] = p[0] + direction[0] * col * spacing;
          x[1] = p[1] + direction[1] * col * spacing;
          x[2] = p[2] + direction[2] * col * spacing;
          points->InsertPoint(cnt++, x);
      }
  }
  // Generate the quads
  vtkIdType pts[4];
  for (unsigned int row = 0; row < rows - 1; row++)
  {
      for (unsigned int col = 0; col < cols - 1; col++)
      {
          pts[0] = col + row * (cols);
          pts[1] = pts[0] + 1;
          pts[2] = pts[0] + cols + 1;
          pts[3] = pts[0] + cols;
          polys->InsertNextCell(4,pts);
      }
  }
  surface->SetPoints(points);
  surface->SetPolys(polys);

  return surface;
}

CMakeLists.txt

cmake_minimum_required(VERSION 2.8)

PROJECT(CurvedReformation)

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

add_executable(CurvedReformation MACOSX_BUNDLE CurvedReformation.cxx )

target_link_libraries(CurvedReformation ${VTK_LIBRARIES})

Download and Build CurvedReformation

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

cd CurvedReformation/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:

./CurvedReformation

WINDOWS USERS

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