管状组织的中轴-元球造型方法

传统的医学体数据造型方法往往局限于将体数据表达为镶嵌在轮廓线族中的三角片集合,或者是简单的三维体元阵列.实际上,生物体的结构相当复杂,采用这些简单的造型方法显然不能适应绘制的要求.文章探讨了适用于气管、血管等管状、多分枝结构的造型方法,采用离散的中轴点表达分枝的拓扑结构,结合基于元球（metaball）的隐式曲面造型方法构造管状组织的模型.这种造型方法不仅可以使管状组织复杂的拓扑结构得以保留,而且保证了分枝之间连接的光滑性.

Modeling Technique Based on Media-axis and Metaball for Vessel Biomedical Structure

The modeling of medical volume data has drawn public attention recently since traditional approaches, such as triangle tiling of the contour surface and 3D array of voxels, do not fit for the efficiently rendering, especially for rendering of vessel structure. In this paper, an algorithm for modeling vessel biomedical structure based on the extraction of medial-axis and the interaction of metaballs is proposed. The authors adopt distance transformation to extract the medial-axis, and use the metaball to describe the structure. The results show that this model not only remains the complicated topological structure, but also assures the smooth shape of rendering result.