[vtkusers] Read Particular pixel value

[Kannan U V]

Hi,
I am trying to find the value of a label at particular point in the image.
The pickedPoint gives me the x,y,z co-ordinate where I should pick the
value. How do I find the image value at that voxel? Since it is a label
image I want to use nearest neighbor interpolation. Can anyone give me
pointers of how to get the label value?


vtkRenderWindowInteractor* iren =
vtkRenderWindowInteractor::SafeDownCast(obj);

iren->SetPicker(picker);

// get event position
int event_pos[2];
iren->GetEventPosition(event_pos);

// update label
QString str;

iren->GetPicker()->Pick(iren->GetEventPosition()[0],
iren->GetEventPosition()[1], 0,
 iren->GetRenderWindow()->GetRenderers()->GetFirstRenderer());
double pickedPoint[3];
iren->GetPicker()->GetPickPosition(pickedPoint);

vtkSmartPointer<vtkImageCast> imageCast =
vtkSmartPointer<vtkImageCast>::New();
vtkSmartPointer<vtkImageData> atlasLabelImageData =
vtkSmartPointer<vtkImageData>::New();

imageCast->SetInput(atlasLabelsReader->GetOutput());
imageCast->SetOutputScalarTypeToUnsignedShort();
imageCast->Update();
atlasLabelImageData = imageCast->GetOutput();
unsigned long labelCellID = (unsigned short)
atlasLabelImageData->FindPoint(pickedPoint);

str.sprintf("(x, y, z) = (%3.2f, %3.2f, %3.2f), Label Value = %f",
pickedPoint[0], pickedPoint[1], pickedPoint[2], labelCellID);

-- 
Thanks,
Kannan
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