RayCastIsosurface
Repository source: RayCastIsosurface
Info
The example uses src/Testing/Data/FullHead.mhd
which references src/Testing/Data/FullHead.raw.gz
.
Description¶
This examples show how volume rendering can produce isosurface-like images. Using vtkOpenGLGPUVolumeRayCastMapper with an isosurface blend mode, two isosurfaces are created using appropriate transfer functions. The effect is similar to what is shown in MedicalDemo2. The user can specify the .mhd file and the two isosurface values. The example uses 500 and 1150 for the two isosurface values. The volume rendering "surfaces" are fuzzier than the hard surfaces created by vtkMarchingCubes in MedicalDemo3.
Usage
RayCastIsosurface.py FullHead.mhd 500 1150
Info
The example uses src/Testing/Data/FullHead.mhd
which references src/Testing/Data/FullHead.raw.gz
.
Other languages
See (Cxx)
Question
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Code¶
RayCastIsosurface.py
#!/usr/bin/env python3
from dataclasses import dataclass
from pathlib import Path
# noinspection PyUnresolvedReferences
import vtkmodules.vtkInteractionStyle
# noinspection PyUnresolvedReferences
import vtkmodules.vtkRenderingOpenGL2
from vtkmodules.vtkCommonColor import vtkNamedColors
from vtkmodules.vtkCommonDataModel import vtkPiecewiseFunction
from vtkmodules.vtkIOImage import vtkMetaImageReader
from vtkmodules.vtkInteractionStyle import vtkInteractorStyleTrackballCamera
from vtkmodules.vtkRenderingCore import (
vtkCamera,
vtkColorTransferFunction,
vtkRenderWindow,
vtkRenderWindowInteractor,
vtkRenderer,
vtkVolume,
vtkVolumeProperty
)
from vtkmodules.vtkRenderingVolumeOpenGL2 import vtkOpenGLGPUVolumeRayCastMapper
def get_program_parameters():
import argparse
description = 'Use volume rendering to produce an iso-surface-like image.'
epilogue = '''
'''
parser = argparse.ArgumentParser(description=description, epilog=epilogue)
parser.add_argument('filename', help='A required filename e.g. FullHead.mhd.')
parser.add_argument('iso1', default=500, type=int, nargs='?', help='The first iso-contour.')
parser.add_argument('iso2', default=1150, type=int, nargs='?', help='The second iso-contour.')
args = parser.parse_args()
return args.filename, args.iso1, args.iso2
def main():
fn, iso1, iso2 = get_program_parameters()
if not Path(fn).is_file():
print(f'The path: {fn} does not exist.')
return
reader = vtkMetaImageReader(file_name=fn)
colors = vtkNamedColors()
mapper = vtkOpenGLGPUVolumeRayCastMapper(auto_adjust_sample_distances=False, sample_distance=0.5)
reader >> mapper
mapper.SetBlendModeToIsoSurface()
iso1_rgb_pt_color = tuple(colors.GetColor3d('flesh'))
iso2_rgb_pt_color = tuple(colors.GetColor3d('ivory'))
color_transfer_function = vtkColorTransferFunction()
color_transfer_function.RemoveAllPoints()
color_transfer_function.AddRGBPoint(iso1, *iso1_rgb_pt_color)
color_transfer_function.AddRGBPoint(iso2, *iso2_rgb_pt_color)
scalar_opacity = vtkPiecewiseFunction()
scalar_opacity.AddPoint(iso1, 0.3)
scalar_opacity.AddPoint(iso2, 0.6)
volume_property = vtkVolumeProperty(shade=True,
interpolation_type=VolumeProperty.InterpolationType.VTK_LINEAR_INTERPOLATION,
color=color_transfer_function, scalar_opacity=scalar_opacity)
volume = vtkVolume(mapper=mapper, property=volume_property)
renderer = vtkRenderer(background=colors.GetColor3d('cornflower'))
renderer.AddVolume(volume)
renderer.ResetCamera()
render_window = vtkRenderWindow(size=(800, 600), window_name='RayCastIsosurface')
render_window.AddRenderer(renderer)
style = vtkInteractorStyleTrackballCamera()
interactor = vtkRenderWindowInteractor()
interactor.render_window = render_window
interactor.interactor_style = style
# Add some contour values to draw iso-surfaces.
volume_property.iso_surface_values.SetValue(0, iso1)
volume_property.iso_surface_values.SetValue(1, iso2)
# Generate a good view.
camera = vtkCamera()
camera.view_up = (0, 0, -1)
camera.position = (0, -1, 0)
camera.focal_point = (0, 0, 0)
renderer.active_camera = camera
renderer.ResetCamera()
camera.Azimuth(30.0)
camera.Elevation(30.0)
camera.Dolly(1.5)
renderer.ResetCameraClippingRange()
render_window.Render()
interactor.Start()
@dataclass(frozen=True)
class VolumeProperty:
@dataclass(frozen=True)
class InterpolationType:
VTK_NEAREST_INTERPOLATION: int = 0
VTK_LINEAR_INTERPOLATION: int = 1
VTK_CUBIC_INTERPOLATION: int = 2
if __name__ == '__main__':
main()