一种新的轮廓线三维地质表面重建方法

在三维地质建模中,由于地质剖面与医学CT有本质上的相似性,因此,轮廓线的三维表面重建技术有广泛的应用。目前,较为成熟的算法并没有考虑地质数据的特殊性,由于地质体形态复杂多变,地质剖面稀疏、数据来源多样等特点,将普适的算法应用到地质建模中,只是解决了重建曲面的合理性,并没有关注曲面的几何质量,导致曲面无法达到地质建模对于模型质量的要求。本文针对地质数据的特点,提出了一种新的轮廓线表面重构方法。在不改变轮廓线连接的合理性与正确性的情况下,通过生成过渡剖面轮廓线,克服传统方法生成曲面过于粗糙的缺点,以提高建模质量。在Creatar三维地质基础平台上,对多种情况的剖面数据实验结果表明,在数据稀疏的情况下达到了良好的建模效果。该方法的扩展模型满足了地质剖面轮廓线建模中复杂地质情况,以及交叉剖面数据的曲面重建,且算法复杂度低,实现简单,有较强的实用性。

High Quality Geological Surface Reconstruction from Planar Contours

In three-dimensional geological modeling, because the geological section and the medical section are essentially similar, the three-dimensional surface reconstruction methods based on contour lines that have been widely used in biomedical modeling are now introduced to geological modeling. But most algorithms from medical modeling that have been applied to geological modeling do not fit specifically for geological data. They only consider the rationality of reconstructed surface, however they concern little about the quality of surface geometry. In geological modeling, there are challenges including the complex and changeable shapes of geological objects, sparse geological section data and various origins of data sources; therefore, the methods that simply connect data could not meet the quality requirements of three-dimensional geological modeling. To overcome it, we consider solving the problem of how to reconstruct high quality triangular surfaces from sparse contour lines in this paper. According to the characteristics of geological data, a new algorithm that improves the quality of geological modeling by interpolating transitional sections is presented. The algorithm deals with geological sections that are stored as vectors and integrate them through a series of manipulations, including: matching features between contour lines that have the same geological property; building a mapping function between each matched pair; generating transitional contour lines; constructing surfaces from transitional contours and original contours. The main process can be summarized as follows: (1) matching geological feature; (2) building mapping function; (3) generating transition model; (4) constructing surface. A standard mathematical model which can resolve contour lines from parallel sections and a extended model that can resolve contour lines from cross sections are both defined in this paper. Some illustrative examples and analytical data are given at the end of this paper to prove that the surface reconstructed by this algorithm has much better quality than traditional ones.