VTK how to Import 3D image data via imageImport on c++ for Volume Rendering
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Thanks for VTK first, it is a nice Tool. But I meet a problem as follow.
Through VTK Python API, I can import/make 3d image data and Volume Rendering as follow:
And the Python code is:
# coding=utf-8 import vtk from numpy import * import random num = 74 # We begin by creating the data we want to render. # For this tutorial, we create a 3D-image containing three overlaping cubes. # This data can of course easily be replaced by data from a medical CT-scan or anything else three dimensional. # The only limit is that the data must be reduced to unsigned 8 bit or 16 bit integers. data_matrix = zeros([num, num, num], dtype=uint8) # data_matrix[0:35, 0:35, 0:35] = 50 # data_matrix[25:55, 25:55, 25:55] = 100 # data_matrix[45:74, 45:74, 45:74] = 150 for i in range(0, num - 1): for j in range(0, num - 1): for k in range(0, num - 1): data_matrix[i:i + 1, j:j + 1, k:k + 1] = 100 # For VTK to be able to use the data, it must be stored as a VTK-image. This can be done by the vtkImageImport-class which # imports raw data and stores it. dataImporter = vtk.vtkImageImport() # The preaviusly created array is converted to a string of chars and imported. data_string = data_matrix.tostring() # dataImporter.CopyImportVoidPointer(data_string, len(data_string)) dataImporter.SetImportVoidPointer(data_matrix) # The type of the newly imported data is set to unsigned char (uint8) dataImporter.SetDataScalarTypeToUnsignedChar() # Because the data that is imported only contains an intensity value (it isnt RGB-coded or someting similar), the importer # must be told this is the case. dataImporter.SetNumberOfScalarComponents(1) # The following two functions describe how the data is stored and the dimensions of the array it is stored in. For this # simple case, all axes are of length 75 and begins with the first element. For other data, this is probably not the case. # I have to admit however, that I honestly dont know the difference between SetDataExtent() and SetWholeExtent() although # VTK complains if not both are used. dataImporter.SetDataExtent(0, 74, 0, 74, 0, 74) dataImporter.SetWholeExtent(0, 74, 0, 74, 0, 74) # The following class is used to store transparencyv-values for later retrival. In our case, we want the value 0 to be # completly opaque whereas the three different cubes are given different transperancy-values to show how it works. alphaChannelFunc = vtk.vtkPiecewiseFunction() alphaChannelFunc.AddPoint(0, 0.0) # alphaChannelFunc.AddPoint(50, 0.001) # alphaChannelFunc.AddPoint(100, 0.02) alphaChannelFunc.AddPoint(150, 0.02) # This class stores color data and can create color tables from a few color points. For this demo, we want the three cubes # to be of the colors red green and blue. colorFunc = vtk.vtkColorTransferFunction() colorFunc.AddRGBPoint(50, 0.0, 0.2, 0.2) colorFunc.AddRGBPoint(100, 0.0, 1.0, 0.0) colorFunc.AddRGBPoint(150, 0.0, 0.0, 1.0) # The preavius two classes stored properties. Because we want to apply these properties to the volume we want to render, # we have to store them in a class that stores volume prpoperties. volumeProperty = vtk.vtkVolumeProperty() volumeProperty.SetColor(colorFunc) volumeProperty.SetScalarOpacity(alphaChannelFunc) # This class describes how the volume is rendered (through ray tracing). compositeFunction = vtk.vtkVolumeRayCastCompositeFunction() # We can finally create our volume. We also have to specify the data for it, as well as how the data will be rendered. volumeMapper = vtk.vtkVolumeRayCastMapper() volumeMapper.SetVolumeRayCastFunction(compositeFunction) volumeMapper.SetInputConnection(dataImporter.GetOutputPort()) # The class vtkVolume is used to pair the preaviusly declared volume as well as the properties to be used when rendering that volume. volume = vtk.vtkVolume() volume.SetMapper(volumeMapper) volume.SetProperty(volumeProperty) # With almost everything else ready, its time to initialize the renderer and window, as well as creating a method for exiting the application renderer = vtk.vtkRenderer() renderWin = vtk.vtkRenderWindow() renderWin.AddRenderer(renderer) renderInteractor = vtk.vtkRenderWindowInteractor() renderInteractor.SetRenderWindow(renderWin) # We add the volume to the renderer ... renderer.AddVolume(volume) # ... set background color to white ... renderer.SetBackground(1, 1, 1) # ... and set window size. renderWin.SetSize(400, 400) # A simple function to be called when the user decides to quit the application. def exitCheck(obj, event): if obj.GetEventPending() != 0: obj.SetAbortRender(1) # Tell the application to use the function as an exit check. # renderWin.AddObserver("AbortCheckEvent", exitCheck) renderInteractor.Initialize() # Because nothing will be rendered without any input, we order the first render manually before control is handed over to the main-loop. renderWin.Render() renderInteractor.Start()
But for c++ API, I can not get the same Volume Rendering through ImageImport.
The following code is the C++ code I write refer to the above Python code. But the result is as follow：
the C++ code I write refer to the above Python code:
#include <iostream> #include
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Honghe -
John Zuhone