Automatic Extraction And Analyses Of Impact Craters Fusing Dataacquired By Chang'E Satellites

The moon is the closest natural object tothe Earth.In 2004,China launched the moon exploration project named “Chang'E” project.The widespread craters on the moon are important data for learning the origin and the evolution of the moon.The large number of craters have provided a good basis for studying the evolution history.However,it will be a waste of time if we extract the craters through artificial way.Therefore,it is always a hot and difficult subject to extract the impact craters automatically.For the difference of lighting conditions,the impact craters of different latitudes show different characteristics in CCD image data,they can be divided into three categories:(1)the craters in high latitudes are divided into two parts: light part and shade part;(2)the craters in low latitude have a more bright edge;(3)the craters in middle latitude are without special characters.Based on the image segmentation,this paper proposes an algorithm to automatically extract the impact craters from images of low latitudes.It is proved that the algorithm can obtain good results in the extraction of craters in the low latitude.However,there are some disadvantages both in the algorithms of this paper and the algorithms raised by others based on the extraction of impact craters in high latitude:(1)The universality of the algorithm is relatively poor.(2)Both algorithms include image preprocessing,so algorithms cannotachieve a good result in small-scall craters.Considering that most of the craters in the CCD image data show a similar circular shape,this paper presents the automatic extraction algorithm of the impact craters based on the HOG feature combined with the SVM classifier.Experiments show that the proposed algorithm can achieve good results for the impact craters extraction in different latitude images,and it has a good performance on the small-scal impact craters.This paper uses the differences of section line toclassify the impact craters and count the paraments of craters surface diameter,bottom diameters and the depth.Then,two different regions of high and low latitudes were selected to calculate the surface diameters,depths and pit bottom diameters of the craters in the two regions.The fractal model was used to obtain the degradation degree of the craters.Finally,the correlation between the surface diameter of the crater and the foundation diameter and depth of the crater is verified,and the consistency of the dynamic environment in the process of crater formation is verified.