关键词: 二义性, 鞍点, 等值面提取, 立方体剖分, 四面体, 插值

Abstract: Iso-surface extraction is an effective manner to study the visualization of three-dimensional data field.To solve the ambiguity question of the existing iso-surface extraction algorithms，a fast iso-surface extraction method which uses saddle to ensure the topology correct is proposed.The accurate iso-surface in the interior of cube is constructed by using the bilinear and the trilinear interpolant method.According to the number of saddle in cube，the cube is tessellated to several tetrahedral cell.This method is only relate to the properties of original data rather than the iso-value，so the cube is only tessellated once when the original data are not changed.Finally，tetrahedral cells are classified into different classes by the class group mehtod，so that only the tetrahedral cell which is intersected with the given iso-surface is visited，the speed of extration is quite improved.Whether the iso-value is smoothly changed or randomly changed，the algorithm is able to maintain a good character.

Key words: ambiguity, saddle, iso-surface extraction, cube tessellation, tetrahedral cell, interpolation