An improved merging algorithm for delaunay meshing on 3D visualization multibeam bathymetric data

Multibeam echo-sounder sonars are indispensably important instruments on seabed mapping and three-dimensional visualization of seafloor can be obtained from multibeam sonar bathymetry via Digital Terrain Modeling. In this paper, we study the algorithms of Delaunay triangulation construction to obtain a seafloor Digital Terrain Model and focus on the problem of the intersection of newly formed triangle and the original triangles during the merging process of two subtriangulations. We present an improved merging method called “bidirectional sew” to obtain a triangle with good-shape once it is formed, and then execute Local Optimization Procedure (LOP) in the seam to finally get the whole Delaunay triangulation. The improved algorithm can effectively reduce the complicacy of the subsequent Local Optimization Procedure (LOP) and enhance the robustness and efficiency of the procedure. After seafloor DTM modeling, by properly setting of color and light, we finally obtain the 3D visualization of seafloor.