3Gonzalez R C, Woods R E. Digital Image Processing, Upper Saddle River[M]. 2nd ed. NJ : Prentice Hall, 2002.
4Matheron G, Serra J. Convexity and Symmetry: Part 2: Image Analysis and Mathematical Morphology: Theoretical Advances[M].London: Academic Press, 1988:359 -375.
5Otsu N. A Threshold Selection Method from Gray Level Histograms[J].IEEE Transactions on Systems, Man, and Cybernetics, 1979,9(1): 62-66.
6Kass M, Witkin A, Terzopoulos D. Snakes:Active Contour Models[J].International Journal of Computer Vision, 1987,1(4):312-331.
7Williams D J, Shah M A. A Fast Algorithm for Active Contours and Curvature Estimation[J].CVGIP:Image Understanding, 1992, 55(1): 14-26.
9He Qizhi, Space Law and Environment, in Space law: development and scope (edited by Nandasiri Jasentuliyana), International Institute of Space Law(1992), at159 - 162.
10Howard A. Baker. space debris: law And Policy in the united states. University of Colorado law Review. 1989. at61.
