MedicalDemo4

VTKExamples/Python/Medical/MedicalDemo4


Code

MedicalDemo4.py

#!/usr/bin/env python

"""
"""

import vtk


def main():
    colors = vtk.vtkNamedColors()

    fileName = get_program_parameters()

    colors.SetColor("BkgColor", [51, 77, 102, 255])

    # Create the renderer, the render window, and the interactor. The renderer
    # draws into the render window, the interactor enables mouse- and
    # keyboard-based interaction with the scene.
    ren = vtk.vtkRenderer()
    renWin = vtk.vtkRenderWindow()
    renWin.AddRenderer(ren)
    iren = vtk.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.)
    reader = vtk.vtkMetaImageReader()
    reader.SetFileName(fileName)

    # The volume will be displayed by ray-cast alpha compositing.
    # A ray-cast mapper is needed to do the ray-casting.
    volumeMapper = vtk.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).
    volumeColor = vtk.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.
    volumeScalarOpacity = vtk.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.
    volumeGradientOpacity = vtk.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.
    volumeProperty = vtk.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.
    volume = vtk.vtkVolume()
    volume.SetMapper(volumeMapper)
    volume.SetProperty(volumeProperty)

    # Finally, add the volume to the renderer
    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).
    camera = ren.GetActiveCamera()
    c = volume.GetCenter()
    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)

    # Set a background color for the renderer
    ren.SetBackground(colors.GetColor3d("BkgColor"))

    # Increase the size of the render window
    renWin.SetSize(640, 480)

    # Interact with the data.
    iren.Start()


def get_program_parameters():
    import argparse
    description = 'Read a volume dataset and displays it via volume rendering.'
    epilogue = '''
    Derived from VTK/Examples/Cxx/Medical4.cxx
    '''
    parser = argparse.ArgumentParser(description=description, epilog=epilogue,
                                     formatter_class=argparse.RawDescriptionHelpFormatter)
    parser.add_argument('filename', help='FullHead.mhd.')
    args = parser.parse_args()
    return args.filename


if __name__ == '__main__':
    main()