Pyramid data structures

• The average pyramid:
  Each node in the average pyramid stores the average of its eight children. A level 0 voxel in the average pyramid is the cubic region supported by 8 data values and contains their average value.
• The and the pyramide:
  Each leave of the pyramide stores the average of the maximum value of the corresponding data point and of its 26 neighbours.
  Each node on higher levels contains the maximum value of its child and its 26 neighbours.
  The pyramide works analogue.
• The pyramid:
  Each voxel contains the Manhattan distance

  

  between the scaled RGBA value derived from sampling the and pyramide.

  Whenever this value is small the region is nearly homogeneous.

• The pyramid: see .

The pyramide has a better worst case behaviour as the pyramid: A large voxel high up in a pyramide may be mostly empty, containing only a very thin yet totally opaque wall and yet have low variance because of the samll amount of variant pixels. This could lead to dramatic image artifacts. The pyramid cannot make this kind of mistakes.