Reslice 3d Raw image using vtkImageReslice

Question

I'm trying to get a 2d slice from a 3d raw image, and I'm viewing the output on a vtkImageViewer2 but I'm getting a blank window.

I'm afraid that i can not make this code shorter because each step in this pipeline is necessary as mentioned here: example that i followed .

also you need a raw image and its header file FullHead.raw.gz which uses FullHead.mhd as a header file.

Here is my code :

#include <vtkPolyDataMapper.h>
#include <vtkActor.h>
#include <vtkRenderer.h>
#include<vtkRenderWindow.h>
#include<vtkRenderWindowInteractor.h>
#include <vtkGenericOpenGLRenderWindow.h>
#include <vtkInteractorStyleTrackballCamera.h>
#include <vtkImageReslice.h>
#include <vtkImageData.h>
#include <vtkLookupTable.h>
#include <vtkImageMapToColors.h>
#include <vtkImageViewer2.h>
#include <vtkMatrix4x4.h>
int main(){
vtkSmartPointer<vtkImageData> imagedata =
 vtkSmartPointer<vtkImageData>::New();
 vtkSmartPointer<vtkRenderWindow> m_renderWindow = 
 vtkSmartPointer<vtkRenderWindow>::New();
  std:string file_path = "FullHead.mhd";
   vtkSmartPointer<vtkMetaImageReader> m_rawImageReader = 
   vtkSmartPointer<vtkMetaImageReader>::New();
   m_rawImageReader->SetFileName(file_path.c_str());
 imagedata = m_rawImageReader->GetOutput();

 double * center = imagedata->GetCenter();

 static double axialElements[16] = {
    1, 0, 0, 0,
    0, 1, 0, 0,
    0, 0, 1, 0,
    0, 0, 0, 1 };
vtkMatrix4x4 *resliceAxes = vtkMatrix4x4::New();
resliceAxes->DeepCopy(axialElements);

resliceAxes->SetElement(0, 3, center[0]);
resliceAxes->SetElement(1, 3, center[1]);
resliceAxes->SetElement(2, 3, center[2]);

vtkSmartPointer<vtkImageReslice> imageReslice =
    vtkSmartPointer<vtkImageReslice>::New();
imageReslice->SetInputConnection(m_rawImageReader- 
>GetOutputPort());
 imageReslice->SetOutputDimensionality(2);
 imageReslice->SetResliceAxes(resliceAxes);
 imageReslice->SetInterpolationModeToLinear();
 // Create a greyscale lookup table
 vtkSmartPointer<vtkLookupTable> table = 
 vtkSmartPointer<vtkLookupTable>::New();
 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
 vtkSmartPointer<vtkImageMapToColors> color = 
  vtkSmartPointer<vtkImageMapToColors>::New();
  color->SetLookupTable(table);
  color->SetInputConnection(imageReslice- 
 >GetOutputPort());

 vtkSmartPointer<vtkImageViewer2> viewier = 
 vtkSmartPointer<vtkImageViewer2>::New();
 viewier->SetInputData(color->GetOutput()); 
 viewier->SetRenderWindow(m_renderWindow); 
 viewier->SetupInteractor(m_renderWindow- 
 >GetInteractor());
 viewier->Render();
  return 0;
 }

It seems that i do not understand this pipeline fully. So, Dose any body know how to this properly?

Answer 1

Before using color->GetOutput() you have to update the Pipeline at least once. VTk uses demand driven pipelines and will only update the parts necessary. So try color->update() before creating the view. Without update the output of your ImageMapToColors filter is empty.