Automatic Detection of Lunar Elliptical Craters from Apollo Image

Impact crater is the major geomorphologic unit of the lunar surface.Its shape and distribution characteristics can provide a large amount of information about the impact history and the lunar evolution process.In this paper,based on the real shape of craters,the authors proposed an automatic extraction method of elliptical craters.The method consists of three steps: image preprocessing,edge detection and ellipse fitting.The last step uses principal component analysis(PCA) of local interesting parameters and Hough transform to derive multiple ellipses.The total accuracy based on a comparison with manually-derived result is over 76%,with the result of larger craters even in excess of 83%.Statistics of the size-frequency distributions of the craters show that,when the length of the long half axis(D) is smaller than 160 meters,the crater number N and D-3.8 has a significant linear relationship.