MedicalDemo4
Repository source: MedicalDemo4
Description¶
Volume rendering of the dataset.
Usage
MedicalDemo4 FullHead.mhd
Note
This original source code for this example is here.
Info
The example uses src/Testing/Data/FullHead.mhd
which references src/Testing/Data/FullHead.raw.gz
.
Question
If you have a question about this example, please use the VTK Discourse Forum
Code¶
MedicalDemo4.java
import vtk.vtkNamedColors;
import vtk.vtkNativeLibrary;
import vtk.vtkRenderWindow;
import vtk.vtkRenderWindowInteractor;
import vtk.vtkRenderer;
import vtk.vtkMetaImageReader;
import vtk.vtkCamera;
import vtk.vtkColorTransferFunction;
import vtk.vtkPiecewiseFunction;
import vtk.vtkFixedPointVolumeRayCastMapper;
import vtk.vtkVolumeProperty;
import vtk.vtkVolume;
public class MedicalDemo4
{
// -----------------------------------------------------------------
// Load VTK library and print which library was not properly loaded
static
{
if (!vtkNativeLibrary.LoadAllNativeLibraries())
{
for (vtkNativeLibrary lib : vtkNativeLibrary.values())
{
if (!lib.IsLoaded())
{
System.out.println(lib.GetLibraryName() + " not loaded");
}
}
}
vtkNativeLibrary.DisableOutputWindow(null);
}
// -----------------------------------------------------------------
public static void main(String args[])
{
//parse command line arguments
if (args.length != 1)
{
System.err.println("Usage: java -classpath ... Filename(.mhd) e.g FullHead.mhd");
return;
}
String inputFilename = args[0];
vtkNamedColors colors = new vtkNamedColors();
double Bgcolor[] = new double[4];
colors.GetColor("SteelBlue", Bgcolor);
// Create the renderer, render window and interactor.
vtkRenderer ren = new vtkRenderer();
vtkRenderWindow renWin = new vtkRenderWindow();
renWin.AddRenderer(ren);
vtkRenderWindowInteractor iren = new vtkRenderWindowInteractor();
iren.SetRenderWindow(renWin);
// The following reader is used to read a series of 2D slices (images)
// that compose the volume. The slice dimensions are set, and the
// pixel spacing. The data Endianness must also be specified. The reader
// uses the FilePrefix in combination with the slice number to construct
// filenames using the format FilePrefix.%d. (In this case the FilePrefix
// is the root name of the file: quarter.)
vtkMetaImageReader reader = new vtkMetaImageReader();
reader.SetFileName(inputFilename);
// The volume will be displayed by ray-cast alpha compositing.
// A ray-cast mapper is needed to do the ray-casting.
vtkFixedPointVolumeRayCastMapper volumeMapper = new vtkFixedPointVolumeRayCastMapper();
volumeMapper.SetInputConnection(reader.GetOutputPort());
// The color transfer function maps voxel intensities to colors.
// It is modality-specific, and often anatomy-specific as well.
// The goal is to one color for flesh (between 500 and 1000)
// and another color for bone (1150 and over).
vtkColorTransferFunction volumeColor = new vtkColorTransferFunction();
volumeColor.AddRGBPoint(0, 0.0, 0.0, 0.0);
volumeColor.AddRGBPoint(500, 1.0, 0.5, 0.3);
volumeColor.AddRGBPoint(1000, 1.0, 0.5, 0.3);
volumeColor.AddRGBPoint(1150, 1.0, 1.0, 0.9);
// The opacity transfer function is used to control the opacity
// of different tissue types.
vtkPiecewiseFunction volumeScalarOpacity = new vtkPiecewiseFunction();
volumeScalarOpacity.AddPoint(0, 0.00);
volumeScalarOpacity.AddPoint(500, 0.15);
volumeScalarOpacity.AddPoint(1000, 0.15);
volumeScalarOpacity.AddPoint(1150, 0.85);
// The gradient opacity function is used to decrease the opacity
// in the "flat" regions of the volume while maintaining the opacity
// at the boundaries between tissue types. The gradient is measured
// as the amount by which the intensity changes over unit distance.
// For most medical data, the unit distance is 1mm.
vtkPiecewiseFunction volumeGradientOpacity = new vtkPiecewiseFunction();
volumeGradientOpacity.AddPoint(0, 0.0);
volumeGradientOpacity.AddPoint(90, 0.5);
volumeGradientOpacity.AddPoint(100, 1.0);
// The VolumeProperty attaches the color and opacity functions to the
// volume, and sets other volume properties. The interpolation should
// be set to linear to do a high-quality rendering. The ShadeOn option
// turns on directional lighting, which will usually enhance the
// appearance of the volume and make it look more "3D". However,
// the quality of the shading depends on how accurately the gradient
// of the volume can be calculated, and for noisy data the gradient
// estimation will be very poor. The impact of the shading can be
// decreased by increasing the Ambient coefficient while decreasing
// the Diffuse and Specular coefficient. To increase the impact
// of shading, decrease the Ambient and increase the Diffuse and Specular.
vtkVolumeProperty volumeProperty = new vtkVolumeProperty();
volumeProperty.SetColor(volumeColor);
volumeProperty.SetScalarOpacity(volumeScalarOpacity);
volumeProperty.SetGradientOpacity(volumeGradientOpacity);
volumeProperty.SetInterpolationTypeToLinear();
volumeProperty.ShadeOn();
volumeProperty.SetAmbient(0.4);
volumeProperty.SetDiffuse(0.6);
volumeProperty.SetSpecular(0.2);
// The vtkVolume is a vtkProp3D (like a vtkActor) and controls the position
// and orientation of the volume in world coordinates.
vtkVolume volume = new vtkVolume();
volume.SetMapper(volumeMapper);
volume.SetProperty(volumeProperty);
double c[] = new double[3];
c=volume.GetCenter();
ren.AddViewProp(volume);
// Set up an initial view of the volume. The focal point will be the
// center of the volume, and the camera position will be 400mm to the
// patient's left (which is our right).
vtkCamera camera = new vtkCamera();
camera.SetViewUp (0, 0, -1);
camera.SetPosition (c[0], c[1] - 400, c[2]);
camera.SetFocalPoint (c[0], c[1], c[2]);
camera.Azimuth(30.0);
camera.Elevation(30.0);
camera.Dolly(0.75);
// Actors are added to the renderer. An initial camera view is created.
// The Dolly() method moves the camera towards the FocalPoint, thereby enlarging the image.
ren.SetActiveCamera(camera);
// Set a background color for the renderer and set the size of the
// render window (expressed in pixels).
ren.SetBackground(Bgcolor);
// Note that when camera movement occurs (as it does in the Dolly()
// method), the clipping planes often need adjusting. Clipping planes
// consist of two planes: near and far along the view direction. The
// near plane clips out objects in front of the plane; the far plane
// clips out objects behind the plane. This way only what is drawn
// between the planes is actually rendered.
ren.ResetCameraClippingRange ();
renWin.SetSize(300, 300);
renWin.Render();
iren.Initialize();
iren.Start();
}
}