def __init__(self, inputs = (1,1)): """ Initialization """ FourierFilters.FourierFilter.__init__(self, inputs) self.filter = vtk.vtkImageButterworthLowPass() self.filterDesc = "Low pass filter in frequency domain using Butterworth algorithm\nInput: Complex image\nOutput: Complex image"
def __init__(self, module_manager):
SimpleVTKClassModuleBase.__init__(
self, module_manager,
vtk.vtkImageButterworthLowPass(), 'Processing.',
('vtkImageData',), ('vtkImageData',),
replaceDoc=True,
inputFunctions=None, outputFunctions=None)
def filterpass(self, lowcutoff=None, highcutoff=None, order=3):
"""
Low-pass and high-pass filtering become trivial in the frequency domain.
A portion of the pixels/voxels are simply masked or attenuated.
This function applies a high pass Butterworth filter that attenuates the
frequency domain image with the function
|G_Of_Omega|
The gradual attenuation of the filter is important.
A simple high-pass filter would simply mask a set of pixels in the frequency domain,
but the abrupt transition would cause a ringing effect in the spatial domain.
:param list lowcutoff: the cutoff frequencies
:param list highcutoff: the cutoff frequencies
:param int order: order determines sharpness of the cutoff curve
"""
#https://lorensen.github.io/VTKExamples/site/Cxx/ImageProcessing/IdealHighPass
fft = vtk.vtkImageFFT()
fft.SetInputData(self._data)
fft.Update()
out = fft.GetOutput()
if highcutoff:
butterworthLowPass = vtk.vtkImageButterworthLowPass()
butterworthLowPass.SetInputData(out)
butterworthLowPass.SetCutOff(highcutoff)
butterworthLowPass.SetOrder(order)
butterworthLowPass.Update()
out = butterworthLowPass.GetOutput()
if lowcutoff:
butterworthHighPass = vtk.vtkImageButterworthHighPass()
butterworthHighPass.SetInputData(out)
butterworthHighPass.SetCutOff(lowcutoff)
butterworthHighPass.SetOrder(order)
butterworthHighPass.Update()
out = butterworthHighPass.GetOutput()
butterworthRfft = vtk.vtkImageRFFT()
butterworthRfft.SetInputData(out)
butterworthRfft.Update()
butterworthReal = vtk.vtkImageExtractComponents()
butterworthReal.SetInputData(butterworthRfft.GetOutput())
butterworthReal.SetComponents(0)
butterworthReal.Update()
caster = vtk.vtkImageCast()
caster. SetOutputScalarTypeToUnsignedChar()
caster.SetInputData(butterworthReal.GetOutput())
caster.Update()
return self._update(caster.GetOutput())
#!/usr/bin/env python
import vtk
from vtk.util.misc import vtkGetDataRoot
VTK_DATA_ROOT = vtkGetDataRoot()
# This script shows the result of an ideal lowpass filter in frequency space.
# Image pipeline
reader = vtk.vtkPNGReader()
reader.SetFileName("" + str(VTK_DATA_ROOT) + "/Data/fullhead15.png")
fft = vtk.vtkImageFFT()
fft.SetDimensionality(2)
fft.SetInputConnection(reader.GetOutputPort())
#fft DebugOn
lowPass = vtk.vtkImageButterworthLowPass()
lowPass.SetInputConnection(fft.GetOutputPort())
lowPass.SetOrder(2)
lowPass.SetXCutOff(0.2)
lowPass.SetYCutOff(0.1)
lowPass.ReleaseDataFlagOff()
#lowPass DebugOn
viewer = vtk.vtkImageViewer()
viewer.SetInputConnection(lowPass.GetOutputPort())
viewer.SetColorWindow(10000)
viewer.SetColorLevel(5000)
#viewer DebugOn
viewer.Render()
# --- end of script --
