The Research And Implementation Of Three-dimension Seabed Terrain Simulation

The digital maps of 3D seabed terrain is flexible, intuitive, lifelike and it contains a large amount of information in auxiliary navigation, and has an extensive application in the navigation field. Therefore it is promising for application that establishing a large-scale 3D seabed terrain model. This paper focuses on establishing 3D seabed terrain model and its visual simulation based on the seabed depth data from the real 2D electronic chart, and establishing a 3D virtual marine simulation unit. It investigates main issues as follows:Firstly, this paper makes a thorough investigation into the features of seabed terrain and 3D interpolation, and discovers that after the conventional interpolation the seabed terrain will appear too smooth, while fractal interpolation can characterize the self-similarity of natural terrain. Although the popular scheme of fractional Brownian motion (fBm) interpolation enjoys higher fidelity than the conventional interpolation, its difficulties for practical application lie in the randomness of algorithm and other reasons. Accordingly, this paper focuses on the deterministic fractal interpolation based on Iterated Function System (IFS).Currently, the application of 3D IFS-based fractal interpolation is limited in the GRID DEM, this paper puts forward a IFS-based fractal interpolation algorithm for the discrete seabed depth data interpolation. Firstly, the sparse seabed depth data from the 2D electronic chart will be changed to the initial grid data of the seabed terrain after the conventional interpolation, and then enjoys terrain details by the IFS-based fractal interpolation algorithm. So that it not only dominates the whole seabed terrain outline but also guarantees that the terrain surface has rough, disorderly and uneven geometric features. The experiment proves that:after the IFS-based fractal interpolation, the DEM rebuilt from the seabed depth data can enjoy higher fidelity of the natural terrain, this algorithm will be promising for application.This paper automatically implements the seabed terrain model in the Creator software, by using the Delaunay transforming algorithm. And the model is carried on the map technology, illumination simulation and color processing. Finally, it renders the seabed environmental and its visualization simulation in the Vega software, therefore the system can display the submarine's trajectory and posture in the seabed terrain environment of the real chart on the three-dimensional way, and can implement manual roaming and automatic roaming of the vivid seabed terrain environment.