三维地形不变性特征描述及其在地形匹配中的应用

Invariant Feature Vector Description for 3D Terrain and Its Application to Terrain Contour Matching

针对实时地形图与基准地形图之间存在旋转、缩放和平移等相似变换的地形匹配问题,提出一种基于地形不变性特征描述的匹配方法。分析了地形的凹凸特征,根据三维地形表面的局部极值点相对位置分布稳定的特点,采用极值点相对位置归一化表示的方法构造了地形的不变性特征向量,基于二维地形特征向量间的距离比较,实现了适应相似变换的地形匹配。该地形描述与匹配方法不依赖于地形的绝对尺度值,仿真实验表明了方法具有较好的实用性,是解决导航定位中存在缩放变换的地形匹配的有效方法。

To deal with the matching of 3D terrains which involves similar transformations of scale, rotation, and shift, a terrain contour matching approach based on the invariant feature description of a 3D terrain is proposed. The concavo-convex feature of a 3D terrain is analyzed first, and then the shape of the terrain is represented by an invariant feature vector which describes the relative position distribution of the vertexes. The feature vector is formed by the distances from the local convex points to the reference convex point in the normal direction and tangent direction of the terrain surface around the reference convex point. The terrain matching approach is realized by calculating and comparing the distances of feature vectors which is robust for the similarity transformation of the terrain. The describing and matching method of a 3D terrain is independent with its absolute scale. The simulated experiments prove the validation of the algorithm. It is suitable for the matching of scaled terrain for navigation.