Attenuation
Repository source: Attenuation
Description¶
This MRI image illustrates attenuation that can occur due to sensor position. The artifact is removed by dividing by the attenuation profile determined manually. This histograms shows how the artifact hides information in the form of scalar value clusters.
Info
See this figure in Chapter 10 the VTK Textbook.
Question
If you have a question about this example, please use the VTK Discourse Forum
Code¶
Attenuation.py
#!/usr/bin/env python3
from dataclasses import dataclass
# noinspection PyUnresolvedReferences
import vtkmodules.vtkRenderingOpenGL2
from vtkmodules.vtkCommonColor import vtkNamedColors
from vtkmodules.vtkCommonDataModel import vtkSphere
from vtkmodules.vtkIOImage import vtkImageReader2Factory
from vtkmodules.vtkImagingCore import (
vtkImageCast,
vtkImageShiftScale
)
from vtkmodules.vtkImagingGeneral import vtkImageGaussianSmooth
from vtkmodules.vtkImagingHybrid import vtkSampleFunction
from vtkmodules.vtkImagingMath import vtkImageMathematics
from vtkmodules.vtkInteractionStyle import vtkInteractorStyleImage
from vtkmodules.vtkRenderingCore import (
vtkImageActor,
vtkRenderWindow,
vtkRenderWindowInteractor,
vtkRenderer
)
def get_program_parameters():
import argparse
description = 'This MRI image illustrates attenuation that can occur due to sensor position.'
epilogue = '''
The artifact is removed by dividing by the attenuation profile determined manually.
'''
parser = argparse.ArgumentParser(description=description, epilog=epilogue,
formatter_class=argparse.RawDescriptionHelpFormatter)
parser.add_argument('filename', help='AttenuationArtifact.pgm.')
args = parser.parse_args()
return args.filename
def main():
colors = vtkNamedColors()
file_name = get_program_parameters()
# Read the image.
reader = vtkImageReader2Factory().CreateImageReader2(file_name)
reader.file_name = file_name
cast = vtkImageCast(output_scalar_type=ImageCast.OutputScalarType.VTK_DOUBLE)
# Get rid of the discrete scalars.
smooth = vtkImageGaussianSmooth(standard_deviations=(0.8, 0.8, 0))
m1 = vtkSphere(center=(310, 130, 0), radius=0)
m2 = vtkSampleFunction(implicit_function=m1, model_bounds=(0, 264, 0, 264, 0, 1), sample_dimensions=(264, 264, 1))
m3 = vtkImageShiftScale(scale=0.000095)
div = vtkImageMathematics(operation=ImageMathematics.Operation.VTK_MULTIPLY)
# Create the actors.
color_window = 256.0
color_level = 127.5
original_actor = vtkImageActor()
original_actor.property.color_window = color_window
original_actor.property.color_level = color_level
filtered_actor = vtkImageActor()
# Define the viewport ranges.
# (xmin, ymin, xmax, ymax)
original_viewport = [0.0, 0.0, 0.5, 1.0]
filtered_viewport = [0.5, 0.0, 1.0, 1.0]
# Set up the pipelines.
p = reader >> cast
p >> original_actor.mapper
(p >> smooth, m2 >> m3) >> div >> filtered_actor.mapper
# Set up the renderers.
original_renderer = vtkRenderer(background=colors.GetColor3d('SlateGray'), viewport=original_viewport)
filtered_renderer = vtkRenderer(background=colors.GetColor3d('LightSlateGray'), viewport=filtered_viewport)
original_renderer.AddActor(original_actor)
filtered_renderer.AddActor(filtered_actor)
original_renderer.ResetCamera()
filtered_renderer.ResetCamera()
render_window = vtkRenderWindow(size=(600, 300), window_name='Attenuation')
render_window.AddRenderer(original_renderer)
render_window.AddRenderer(filtered_renderer)
render_window_interactor = vtkRenderWindowInteractor()
style = vtkInteractorStyleImage()
render_window_interactor.interactor_style = style
render_window_interactor.render_window = render_window
render_window_interactor.Initialize()
render_window_interactor.Start()
@dataclass(frozen=True)
class ImageCast:
@dataclass(frozen=True)
class OutputScalarType:
VTK_CHAR: int = 2
VTK_UNSIGNED_CHAR: int = 3
VTK_SHORT: int = 4
VTK_UNSIGNED_SHORT: int = 5
VTK_INT: int = 6
VTK_UNSIGNED_INT: int = 7
VTK_LONG: int = 8
VTK_UNSIGNED_LONG: int = 9
VTK_FLOAT: int = 10
VTK_DOUBLE: int = 11
@dataclass(frozen=True)
class ImageMathematics:
@dataclass(frozen=True)
class Operation:
VTK_ADD: int = 0
VTK_SUBTRACT: int = 1
VTK_MULTIPLY: int = 2
VTK_DIVIDE: int = 3
VTK_INVERT: int = 4
VTK_SIN: int = 5
VTK_COS: int = 6
VTK_EXP: int = 7
VTK_LOG: int = 8
VTK_ABS: int = 9
VTK_SQR: int = 10
VTK_SQRT: int = 11
VTK_MIN: int = 12
VTK_MAX: int = 13
VTK_ATAN: int = 14
VTK_ATAN2: int = 15
VTK_MULTIPLYBYK: int = 16
VTK_ADDC: int = 17
VTK_CONJUGATE: int = 18
VTK_COMPLEX_MULTIPLY: int = 19
VTK_REPLACECBYK: int = 20
if __name__ == '__main__':
main()