测地自旋图:三维物体局部形状描述符

Geodesic-spin-image:local shape descriptor of 3D object

针对自旋图中欧氏测量存在歧义、形状信息存在丢失的现象,提出一种新的三维物体表面局部形状描述符:测地自旋图(Geodesic-spin-image,GSI)。GSI采用测地距离取代欧氏距离限定局部支持区域;GSI在自旋图的基础上,还引入了3个新的特征,以补偿自旋图在方位角上的信息丢失。这3个特征为:局部支持区域在描述点切平面上投影的长轴长度、短轴长度,以及局部支持区域形心到描述点切平面的距离。基于GSI描述改进了现有自旋图匹配算法,首先基于3个新特征进行粗略匹配,而后基于测地支持区域内的自旋图进行精确匹配,以提高识别效率。仿真实验结果表明:相比于标准自旋图方法,该方法提供的物体局部形状信息更丰富,具有更高的目标分辨能力和匹配识别效率。

Geodesic-spin-image （GSI）, a new three-dimensional（3D） local shape descriptor, was proposed to solve the problems of ambiguous Euclidean measure and insufficient shape information description when utilizing the Spin Image （SI） descriptor. The local support region of GSI was defined by Geodesic measure instead of Euclidean measure. Besides, three new features were also introduced to compensate the azimuth information loss while these features were long axis length and short axis length of the support region＇s projection onto the tangent plane of the given point, and the distance from the centroid of the support region to the tangent plane. Based on the GSI, matching strategy of SI was modified through a combination of coarse matching utilizing the three new features and fine matching utilizing SI defined by geodesic measure, so as to improve the matching efficiency. Simulation experiment results show that compared with the original SI method, the proposed GSI descriptor is proved to provide more shape information and be more discriminative, and its matching strategy is more efficient.