MedicalVisualization

DVR Sampling

DVR Principles | | Optical Effects

In order to simulate the photons behaviour, light rays are cast through the volume in direction of the viewer (ray casting). On its way through the gaseous material the effects the photons undergo are accumulated. This is done by sampling the ray in discrete steps. Each single step contributes to the appearance of the same image point.

Sampling can be uniform or adaptive.

  • according to Shannons sampling theoreme two samples per voxel are necessary.
  • in practice one sample per voxel is mostly sufficient.

Ray Casting:

Adaptive Ray Casting:

  • Adapts to non-uniformities of the volume
  • Best known adaptive technique: Empty Space Leaping


DVR Principles | | Optical Effects

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