Image cutting is done using the Python version of VTK

This is the fifth day of my participation in the November Gwen Challenge. Check out the details: The last Gwen Challenge 2021

This article describes cutting the surface rendering model using the Python version of VTK

This section describes the modules that will be used

1. Read 2d image sequence to complete surface rendering

See read 2d sequence display for details

Vtk.vtkoutlinefilter (

This space is equivalent to generating the contour line of the rendering model. For example, if the size of the 3D image is (256x256x200), then this control will generate a rectangular frame with length, width and height 256x256x200 respectively

Details: VTK official documentation

3, the implicit function graphic module VTK. VtkImplicitPlaneWidget ()

Use this module to flexibly adjust the selected plane vtkImplicitPlaneWidget official document

4, VTK. VtkClipPolyData ()

The shear result of VTKclipPolydata is divided into upper and lower parts according to the tangent plane normals, with corresponding output interface in the interface

VtkClipPolyData official document

Cutting effect display

The code is as follows:

import vtk


def main() :
    arender = vtk.vtkRenderer()
    arender.SetViewport(0.0.0.0.5.1.0)
    renWin = vtk.vtkRenderWindow()
    renWin.AddRenderer(arender)
    iren = vtk.vtkRenderWindowInteractor()
    iren.SetRenderWindow(renWin)

    # Reader = vtk.vtkMetaImageReader()
    # Reader.SetFileName("bbb.mhd")
    # Reader.Update()
# Read pictures, surface drawing
    Reader = vtk.vtkPNGReader()
    Reader.SetNumberOfScalarComponents(1)
    Reader.GetOutput().GetOrigin()
    Reader.SetDataByteOrderToLittleEndian()
    Reader.SetFileDimensionality(3)
    Reader.SetDataExtent(0.512.0.512.0.226)
    Reader.SetFilePrefix("E:/qct_data/in_out_data/in_data/inner/label/22/")
    #Reader.SetFilePrefix("C:/Users/deng5/Desktop/2/48/")
    Reader.SetFilePattern("%s%d.png")
    Reader.SetDataSpacing(1.1.1)  # Volume Pixel
    Reader.Update()
    
See the python-vtk Complete surface rendering article for more details
    skinExtractor = vtk.vtkContourFilter()
    skinExtractor.SetInputConnection(Reader.GetOutputPort())
    skinExtractor.SetValue(0.1)
    skinExtractor.ComputeGradientsOn();
    skinExtractor.ComputeScalarsOn();
    smooth = vtk.vtkSmoothPolyDataFilter()
    smooth.SetInputConnection(skinExtractor.GetOutputPort())
    smooth.SetNumberOfIterations(100)

    skinNormals = vtk.vtkPolyDataNormals()
    skinNormals.SetInputConnection(smooth.GetOutputPort())
    skinNormals.SetFeatureAngle(50)

    skinStripper = vtk.vtkStripper()
    skinStripper.SetInputConnection(skinNormals.GetOutputPort())

    skinMapper = vtk.vtkPolyDataMapper()
    skinMapper.SetInputConnection(skinStripper.GetOutputPort())
    skinMapper.ScalarVisibilityOff()

    skin = vtk.vtkActor()

    skin.SetMapper(skinMapper)
Define an image boundary control
    outlineData = vtk.vtkOutlineFilter()
    outlineData.SetInputConnection(Reader.GetOutputPort())

    mapOutline = vtk.vtkPolyDataMapper()
    mapOutline.SetInputConnection(outlineData.GetOutputPort())

    outline = vtk.vtkActor()
    outline.SetMapper(mapOutline)
    outline.GetProperty().SetColor(0.0.0)

    aCamera = vtk.vtkCamera()
    aCamera.SetViewUp(0.0, -1)
    aCamera.SetPosition(0.1.0)
    aCamera.ComputeViewPlaneNormal()
    aCamera.Azimuth(30.0)
    aCamera.Elevation(30.0)
    aCamera.Dolly(1.5)
    arender.AddActor(outline)
    arender.AddActor(skin)
    #splineActor.GetProperty().SetLineWidth(5)
    #arender.AddActor(splineActor)
    #arender.AddActor(pointActor)
    arender.SetActiveCamera(aCamera)
    arender.ResetCamera()
    arender.SetBackground(2..3..4.)
    arender.ResetCameraClippingRange()

    renWin.SetSize(1000.1000)
    style = vtk.vtkInteractorStyleTrackballCamera()
    iren.SetInteractorStyle(style);
Define the cutter
    global cliper
    cliper = vtk.vtkClipPolyData()
    cliper.SetInputData(skinStripper.GetOutput())
# Define the plane implicit function
    implicitPlaneWidget = vtk.vtkImplicitPlaneWidget()
    implicitPlaneWidget.SetInteractor(iren)
    implicitPlaneWidget.SetPlaceFactor(1.25)
    implicitPlaneWidget.SetInputData(skinStripper.GetOutput())
    implicitPlaneWidget.PlaceWidget()
    global coneSkinActor
    coneSkinActor = vtk.vtkActor()
    coneSkinActor.SetMapper(skinMapper)

    rRenderer = vtk.vtkRenderer()
    rRenderer.SetBackground(0.2.0.3.0.5)
    rRenderer.SetViewport(0.5.0.0.1.0.1.0)

    coneSkinActor.RotateZ(90)
    rRenderer.AddActor(coneSkinActor)

    renWin.AddRenderer(rRenderer)
    # correlation CallBack function
    implicitPlaneWidget.AddObserver("EndInteractionEvent", my_call_back)
    implicitPlaneWidget.On()


    renWin.Render()
    iren.Initialize()
    iren.Start()

# CallBack function
def my_call_back(pWidget,ev) :
# indicates that the function is fired when the pWidget control changes
    if (pWidget):
        print(pWidget.GetClassName(), "Event Id:", ev)
        planeNew = vtk.vtkPlane()
        Get the plane in the pWidget and assign the plane value planeNew
        pWidget.GetPlane(planeNew)
        #cliper Sets the plane of clipper cliper to planeNew
        cliper.SetClipFunction(planeNew)
        planeNew.GetNormal()
        cliper.Update();
        Pass the trimmed model to another window
        clipedData = vtk.vtkPolyData()
        clipedData.DeepCopy(cliper.GetOutput())

        coneMapper = vtk.vtkPolyDataMapper()
        coneMapper.SetInputData(clipedData)
        coneMapper.ScalarVisibilityOff()
        coneSkinActor.SetMapper(coneMapper)
        print("Plane Normal = "+str(planeNew.GetNormal()))
        print("Plane Origin = "+str(planeNew.GetOrigin()))
        

main()



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