[vtkusers] Picking a pixel from an image (works, but ...)

[John Smith]

Dear all,

I have a little problem picking a pixel from a vtkImageViewer2. I use vtkPointPicker for that. Here's the procedure I use:

1.Get mouse location in scene space:
double point[3];
picker->GetMapperPosition(point);
2.Get correct mapped z-location:
double spacing[3];
imageViewer->GetInput()->GetSpacing(spacing);
point[2] = imageViewer->GetSlice() * spacing[2];
3.Get the actual volume index of the mouse over pixel;
int index = imageViewer->GetInput()->FindPoint(point);
double* scalarPointer = (double*)imageViewer->GetInput()->GetScalarPointer();
double intensity = scalarPointer[index];

4.Printing the picked pixel coordinates and the pixel intensity:
cerr << "(" << point[0] << ", " << point[1] << ", " << point[2] << "): "  << intensity;

The problem I have is that I always get wrong values comparing to other programs. Maybe I miss something out. 

Thank you in advance.

Regards,

J.





      
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