小行星三维地形模型几何重建方法

3D Asteroid Terrain Model Reconstruction Based on Geometric Method

小行星全球测绘对深空探测定点着陆具有重要意义.通过对绕飞段光学敏感器拍摄的序列图像进行几何立体重建方法的研究,可以实现探测器位姿信息未知情况下的三维地形建模.综合小行星表面特性、小行星运行特点与探测器飞行需求,首先通过全局的运动恢复结构完成小行星稀疏点云重建,再利用多视角场景重建对点云进行稠密化得到致密均匀的网格.然后采用隼鸟号探测器绕飞阶段实测影像,对小行星糸川(25143 Itokawa)的三维地形进行仿真重建,分辨率为0.36 m;并在光学实验室对3D打印的小行星比例模型进行模拟观测实验,得到重建分辨率为0.67 m.最后通过点云配准,进一步验证方法的有效性.结果表明,本方法稳定性较强,在分辨率要求在米级范围内的情况下,能够较好地针对小行星表面地形进行三维重建.

Asteroid global mapping is important for deep-space exploration and landing.Via studying the geometric stereo reconstruction method of the sequence images taken by the optical sensor,the purpose of a 3 D terrain modeling can be achieved under the condition that the detector pose information is unknown.Based on the asteroid’s surface characteristics,the asteroid’s operational characteristics and the flight requirements of the detector,the asteroid’s sparse point cloud reconstruction is first completed by the global motion recovery structure,and the point cloud is densified by dense multi-view scene reconstruction to obtain a dense and uniform grid.Then,using the ostrich detector to measure the image during the flight phase,the 3 D terrain of the asteroid 25143 Itokawa is reconstructed with a resolution of 0.36 m.The 3 D printed asteroid scale model is simulated in the optical laboratory.During the observation process,the reconstruction resolution is 0.67 m.Finally,the validity of the method is further verified by point cloud registration.The results show that the method is stable.Under the condition that the resolution requirement is within the meter range,it can better reconstruct the surface topography of the asteroid.