针对深空探测器光学导航技术的需要,提出了行星表面陨石坑导航路标的提取与匹配方法。陨石坑是行星表面最显著的地形特征,在光照条件下,陨石坑具有清晰的几何轮廓。结合光照方向,通过陨石坑边缘的检测、边缘配对以及形状参数拟合等处理实现陨石坑的提取。对检测出的陨石坑,基于平面二次曲线的几何不变特性,采用投票策略实现与陨石坑数据库的匹配,并设计陨石坑误匹配及失配的校正策略,从而有效地确定陨石坑在目标天体表面的全局位置。最后通过嫦娥一号获得的目表图像验证了所提方法的有效性和可行性。
This article presents a crater landmark detection and matching method for pinpoint navigation for planetary exploration. Craters are the most notable terrain features with clear outlines in lighting conditions. While taking into consideration the direction of the lighting source, the craters are detected through edge detection, edge clustering of the same crater and ellipse fitting. Based on the geometric invariants of coplanar con ics, the voting strategy is used to match the detected craters with the crater database. Besides, a false match and miss match revision strategy is proposed to obtain the crater's accurate global position. Lunar surface images obtained by Chang' e-1 are given to show the feasibility of the proposed method.