Question

我想打开两个nrrd文件，然后将这两个文件重叠。此步骤的第一步是使用vtk的vktImageData或Mapper打开nrrd文件。我编写了代码来执行此操作，但是运行它时只显示黑屏。

我已经通过将Image替换为一个卷并一遍又一遍地打印两个文件来做到这一点。但是，当我尝试对此结果进行颜色映射时，我注意到颜色映射的坐标与两个文件的坐标不匹配。此时，我没有使用用于渲染对象的同一映射器和颜色映射的映射器，并且我认为坐标是不同的。

因此，我从头开始使用相同的映射器来呈现文件和颜色映射。

import vtk


def main():
    renWin = vtk.vtkRenderWindow()
    renderer = vtk.vtkRenderer()
    renWin.AddRenderer(renderer)
    iren = vtk.vtkRenderWindowInteractor()
    iren.SetRenderWindow(renWin)


    reader = vtk.vtkNrrdReader()
    reader.SetFileName('Segmentation-label_2.nrrd')
    reader.Update()

    mapper = vtk.vtkPolyDataMapper()
    mapper.SetInputConnection(reader.GetOutputPort())

    actor = vtk.vtkActor()
    actor.SetMapper(mapper)

    renderer.AddActor(actor)

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

if __name__ == "__main__":
    main()

运行此代码时，仅输出黑屏。我搜索了很多数据，但是我不知道问题出在哪里。

感谢您的答复。

Answer 1

通过调整https://vtk.org/Wiki/VTK/Examples/Python/DataManipulation/Cube.py中给出的示例，这将为您的3D图像数据加载您经过的2D切片。

#!/usr/bin/env python

import vtk

# Start by loading some data.
reader = vtk.vtkNrrdReader()
reader.SetFileName('Segmentation-label_2.nrrd')
reader.Update()    

# Calculate the center of the volume
reader.Update()
(xMin, xMax, yMin, yMax, zMin, zMax) = reader.GetExecutive().GetWholeExtent(reader.GetOutputInformation(0))
(xSpacing, ySpacing, zSpacing) = reader.GetOutput().GetSpacing()
(x0, y0, z0) = reader.GetOutput().GetOrigin()

center = [x0 + xSpacing * 0.5 * (xMin + xMax),
          y0 + ySpacing * 0.5 * (yMin + yMax),
          z0 + zSpacing * 0.5 * (zMin + zMax)]

# Matrices for axial, coronal, sagittal, oblique view orientations
axial = vtk.vtkMatrix4x4()
axial.DeepCopy((1, 0, 0, center[0],
                0, 1, 0, center[1],
                0, 0, 1, center[2],
                0, 0, 0, 1))

coronal = vtk.vtkMatrix4x4()
coronal.DeepCopy((1, 0, 0, center[0],
                  0, 0, 1, center[1],
                  0,-1, 0, center[2],
                  0, 0, 0, 1))

sagittal = vtk.vtkMatrix4x4()
sagittal.DeepCopy((0, 0,-1, center[0],
                   1, 0, 0, center[1],
                   0,-1, 0, center[2],
                   0, 0, 0, 1))

oblique = vtk.vtkMatrix4x4()
oblique.DeepCopy((1, 0, 0, center[0],
                  0, 0.866025, -0.5, center[1],
                  0, 0.5, 0.866025, center[2],
                  0, 0, 0, 1))

# Extract a slice in the desired orientation
reslice = vtk.vtkImageReslice()
reslice.SetInputConnection(reader.GetOutputPort())
reslice.SetOutputDimensionality(2)
reslice.SetResliceAxes(sagittal)
reslice.SetInterpolationModeToLinear()

# Create a greyscale lookup table
table = vtk.vtkLookupTable()
table.SetRange(0, 2000) # image intensity range
table.SetValueRange(0.0, 1.0) # from black to white
table.SetSaturationRange(0.0, 0.0) # no color saturation
table.SetRampToLinear()
table.Build()

# Map the image through the lookup table
color = vtk.vtkImageMapToColors()
color.SetLookupTable(table)
color.SetInputConnection(reslice.GetOutputPort())

# Display the image
actor = vtk.vtkImageActor()
actor.GetMapper().SetInputConnection(color.GetOutputPort())

renderer = vtk.vtkRenderer()
renderer.AddActor(actor)

window = vtk.vtkRenderWindow()
window.AddRenderer(renderer)

# Set up the interaction
interactorStyle = vtk.vtkInteractorStyleImage()
interactor = vtk.vtkRenderWindowInteractor()
interactor.SetInteractorStyle(interactorStyle)
window.SetInteractor(interactor)
window.Render()

# Create callbacks for slicing the image
actions = {}
actions["Slicing"] = 0

def ButtonCallback(obj, event):
    if event == "LeftButtonPressEvent":
        actions["Slicing"] = 1
    else:
        actions["Slicing"] = 0

def MouseMoveCallback(obj, event):
    (lastX, lastY) = interactor.GetLastEventPosition()
    (mouseX, mouseY) = interactor.GetEventPosition()
    if actions["Slicing"] == 1:
        deltaY = mouseY - lastY
        reslice.Update()
        sliceSpacing = reslice.GetOutput().GetSpacing()[2]
        matrix = reslice.GetResliceAxes()
        # move the center point that we are slicing through
        center = matrix.MultiplyPoint((0, 0, sliceSpacing*deltaY, 1))
        matrix.SetElement(0, 3, center[0])
        matrix.SetElement(1, 3, center[1])
        matrix.SetElement(2, 3, center[2])
        window.Render()
    else:
        interactorStyle.OnMouseMove()


interactorStyle.AddObserver("MouseMoveEvent", MouseMoveCallback)
interactorStyle.AddObserver("LeftButtonPressEvent", ButtonCallback)
interactorStyle.AddObserver("LeftButtonReleaseEvent", ButtonCallback)

# Start interaction
interactor.Start()
del renderer
del window
del interactor

如果我使用vtk打开nrrd文件，则仅输出黑屏

1 个答案: