[vtkusers] vtkDICOMImageReader volume rendering problem

[Peter]

hi my friends,

when i am trying to do some volume rendering using
vtkDICOMImageReader, it shows some error likes this.

ERROR: In C:\VTK4.4\Rendering\vtkVolumeRayCastMapper.cxx, line 325
vtkOpenGLVolumeRayCastMapper (026A2BB0): Cannot volume render data of
type short, only unsigned char or unsigned short.


my code is roughly like:

=======

vtkDICOMImageReader reader
      reader SetDataByteOrderToLittleEndian;
      reader SetDirectoryName "C:\\dicom"
      [reader GetOutput] ReleaseDataFlagOn
      reader SetDataSpacing 0.938 0.938 1.3
      reader Update

vtkPiecewiseFunction volOpacityTransferFunctiono
...
...

vtkColorTransferFunction colorTransferFunction
....
....

vtkVolumeProperty vol_prop
vol_prop SetColor colorTransferFunction
vol_prop SetScalarOpacity volOpacityTransferFunction
vol_prop SetInterpolationTypeToLinear
vol_prop ShadeOn

vtkVolumeRayCastCompositeFunction comp_func

vtkVolumeRayCastMapper  volmap
volmap SetInput [reader GetOutput]
volmap SetVolumeRayCastFunction comp_func

volmap SetSampleDistance 1.0

vtkVolume vol
vol SetProperty vol_prop
vol SetMapper volmap
ren1 AddVolume vol

===============


can anyone out there help me out for how to use vtkDICOMImageReader to
do some volume rendering. it seems fine when using vtkVolume16Reader.


Thank you very much

Yours

Peter Pan