期刊名称：ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences
印刷版ISSN：2194-9042
电子版ISSN：2194-9050
出版年度：2003
卷号：XXXIV-3/W13
出版社：Copernicus Publications
摘要：A proper representation of the surface of the earth and the man-made object build upon it is needed as a data source for environmental modelling and planning. One way to represent the terrain given by a set of surface points is to construct a Delaunay Triangular Irregular Network (DTIN). This DTIN is believed to give the 'best' triangular tessellation as the Delaunay empty circle criterion opts for well-formed 'fat' triangles and the resulting triangulation maximizes the smallest angle within each triangle. This idea is true for many computational geometry applications, but it is not valid for visual and analytical geo-computational queries dependent on the height of the surface. This limitation is given by the fact that the distribution of the triangular mesh is defined in the two-dimensional XY-plane and the Z-value of the surface points is not taken into account by the Delaunay empty circle criterion at all. Alternatively, Data Dependent Triangulations (DDTINs) aim to identify which triangulation over a given set of points will optimize some quality, i.e. the minimal spatial area of the surface or the volume below the resulting surface. The Z-value of the surface points is now taken into account, but still no certainty can be given that the derived TIN represents the actual surface. Hence, the reconstruction of the surface given by only the set of surface points is not unambiguous. This paper describes a surface reconstruction method based on the Delaunay Tetrahedronised Irregular Network (DTEN), which tessellates the 3D-space with non-overlapping, adjacent, tetrahedrons. The DTEN is constructed by the Delaunay criterion, resulting in a tessellation where the circumscribing sphere of each tetrahedron is empty. The approach presented in this paper is new in that not only the surface points are included into the DTEN, but also the observation lines, i.e. the lines-of-sight between the observer (i.e. an airborne or tripoded laser altimeter) and the targets (the measured points). These observation lines add the information needed to extract the Surface TIN (STIN) from this DTEN. The observation lines can also be artificial or simulated for this purpose. The STIN approach presented in this paper is a full 3D-implementation and refinement of the research presented in (Verbree, 2001).
关键词：Conforming Delaunay Tetrahedronized Networks; Surface Reconstruction; Data Dependent Triangulations
