中文摘要：

陨石坑是月球表面最重要的地形特征，对于研究月球的地质状况和地理状况具有重要的意义。充分考虑低太阳高度角影像中陨石坑特殊的拓扑结构和灰度分布特点，提出一种新的基于光照方向的陨石坑边缘连接方法，综合边缘线判别、边缘线组合、陨石坑判别的陨石坑筛选三步法，形成一套完整的低太阳高度角月球影像陨石坑自动提取流程。用低太阳高度角Lunar Orbit影像进行实验，检测成功率达到了73．9％，表明该方法对于低太阳高度角月球影像陨石坑的自动提取有较好的适用性。

英文摘要：

Lunar crater is the most important terrain feature of the lunar surface, so craters have important meaning in the study of lunar geology and geography. Considering the special topology and gray distribution characteristics of lunar images under low solar elevation angle, an automatic crater extraction process is developed in this paper. This process mainly includes a new crater edge connection method based on the solar azimuth, the crater selection procedure combines discrimination of crater edges, matching of crater edges and crater screening. Lunar Orbit images of low solar elevation angle are used to do an experiment and the successful detection rate is 73.9%. The result shows that this process is useful for crater automatic detecting of lunar images under low solar elevation angle.