一种新的地景模型简化与快速绘制方法

A New Algorithm for Large-Scale Terrain Simplification and Data Extraction

地景模型是一类重要模型,它可以广泛应用在航空、航天与军事指挥等领域,但由于其数据量极大,如何实现快速绘制是一个难题。本文在分析地景模型数据特点的基础上,提出了地景模型简化的判决准则,并根据该准则提出了基于视点与图像分辨率的区域数据抽取与网格重构方法,以及基于法矢量(梯度)的模型简化及其LOD层次表示,最后进行了实验验证。结果表明,该方法数据压缩量大,绘制速度快,且逼真度无明显变化。

The LOD (Levels of Detail) method based on model simplification is an effective one to realize fast-speed rendering of large-scale terrain model. This paper gives a new algorithm for large-scale terrain simplification. First, it analyses the data characteristics of large-scale terrain model, gives two judging criteria of simplification. Second, based on these rules, gives an approach of viewpoints-based data extraction from terrain; according to this approach, terrain data can be compressed effectively, and then new terrain mesh will be reconstructed according to image resolution. Third, this gives a simplification algorithm based on averaged normal vectors; according to this algorithm, terrain simplification can be fulfilled after only one cycle without complicated iterative operation. At last, gives a group of experiment results, which illustrate that the algorithm given has the characteristics of a large data compression ratio, higher rendering speed and better image accuracy.