283 / 2023-10-09 10:19:28

Three-dimensional reconstruction and Geometric Morphology Analysis of Lunar Small Craters within the Patrol Range of the Yutu-2 Rover

Small crater; Yutu-2; geometrical morphology analysis; terrain reconstruction; visual positioning

Craters on the lunar surface are the most direct basis for the study of geological processes, and are of great significance to the study of lunar evolution. In order to fill the research gap of small craters (diameter less than 3 m), we focuses on the small craters around the moving path of the Yutu 2 lunar rover, and carries out 3D reconstruction and geometrical morphology analysis on them. First, a self-calibration model with multiple feature constraints is used to calibrate the navigation camera and obtain the internal and external parameters. Then, the sequence images with overlapping regions from neighboring stations are used to obtain the precise position of the rover through the bundle adjustment (BA) method. After that, a cross-scale cost aggregation for stereo matching network is proposed to obtain the parallax map, which can further obtain 3D point clouds of the lunar surface. Finally the indexes of the craters are extracted (Diameter D、Depth d、Depth-diameter ratio d_r), and the different indicators were fitted and analyzed. The results suggested that the CscaNet has an anomaly percentage value of 1.73% in the KITTI2015 dataset, and an EPE of 0.74px in the SceneFlow dataset, both of which are superior to GC-Net, DispNet, and PSMnet, and have higher reconstruction accuracy. The correlation between D and d is high and exhibits a positive correlation, while the correlation between D and d_r is low. The geometric morphology expressions of small craters fitted by using D and d are significantly different from the expressions proposed by other scholars for large craters. This study provides a priori knowledge for the subsequent Von Karmen crater survey mission in the SPA basin.