多等值面抽取算法

new multi-isosurfaces extraction algorithm is proposed, which can extract multiple isosurfaces in one pass. Based on the Skeleton Climbing method, intersections between the multi-isosurfaces and the grid edges (1-skeleton), faces (2-skeleton) and cubes (3-skeleton) are computed and processed in a uniform way. Because the sharing vertices, edges and surfaces in the junctions of the multi-isosurfaces are obtained, the topological connection information among the multi-isosurfaces can be maintained explicitly. The kernel of the proposed algorithm how to compute the intersections between the multi-isosurfaces and the voxel, are discussed in detail. Similar to the classical isosurface algorithms, the ambiguity and singularity are also carefully discussed step by step. Compared with the classical isosurface algorithms, the multi-isosurfaces not only can express more details of the volume data, but also is convenient for further processing. In addition, we believe that many potential applications of the proposed algorithm will benefit from our algorithm.