[vtkusers] Strange stereo effect with Volume Rendering

[Valeria Gallo]

Hi, I have just implemented a passive stereo effect in C++ with VTK
libraries using the CrystalEyes method on a NVidia Quadro Graphics Card,
with two projectors, a not-depolarizing screen and linear polarized lens and
glasses. This is the code:

 

renWin->SetStereoCapableWindow(3);

renWin->StereoRenderOn();

renWin->SetStereoTypeToCrystalEyes();

renderer->GetActiveCamera()->ParallelProjectionOff();

renderer->GetActiveCamera()->SetEyeAngle(3.0);

 

The stereo effect is perfect if the object is generated (from DICOM images)
with a Surface rendering, whilst with the Volume Rendering the 3D image
generated is confused.

The strange thing is that if I set a negative "eye angle" the stereo effect
on the Volume Rendering is good but reversed (I see the reconstructed object
beyond the plane of the screen).

Using the surface rendering, instead, the effect is perfect in both
directions (but I'm interested that the object poke through the plane of the
screen).

 

I'm thinking the problem could be the way the ray casting method is
implemented in the Volume rendering: probably the camera and the viewpoint
are not in the same point.

I think this also because using a SetEyeAngle(0.3) on the Volume Rendered
image gives me roughly the same effect of a SetEyeAngle(3.0) on the Surface
Rendered object, therefore I think the images for left and right view are
generated, with the Volume Rendering, in a different way in comparison with
the Surface Rendering ones.

 

Someone could help me to address my problem?

 

Thanx,

Valeria

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