Fast Stereo Volume Rendering [](2nd Part)

Segment composition scheme for stereo shear warp.

• Use the Shear-Warp Approach (Image quality decided by volume resolution)
  
• The left-rays ( See figure ) and right-rays are perpendicular to the same volume slices in the sheared object space.
• Shear factor for the nth slice.

  

• The distance between left and right eye .

  

• Then

  

    
  Figure: Relation between viewing rays and volume coordinate system
  

    
  Figure: Scaling marching for stereo shear-warp
  

  The offset between left and right eye projection is the same for all sampling points on the same slice.
  

  

  After some calculations (See []). Assuming distance between eyes is 5 degrees (three times bigger than the recommended). They get to the conclusion that:

  

  This states that on the average the left eye-result of at least five slices can be re-projected to the right-image when the sampling rate is the same that the volume sampling distance.
  So apply Shear-warp to the left image and re-project the composition result of several left eye slices to the right image.
  To assure correct early ray termination. Intermediate image scan-line are marched simultaneous with the voxel scanline. If in both scanlines pixel is opaque it is skipped ( See figure ) .

  Balanced images can be generated placing the point in the middle eye.