AUTOMATIC CHARACTERIZATION OF LUNAR IMPACT CRATER DEGRADATION

In this work we propose a semi-automatic method for characterizing and classifying degradation activities for lunar craters based on a recent approach [1] that uses Chebyshev polynomials to represent craters.

Degradation of lunar impact craters can be studied by comparing and contrasting topographic descriptors obtained from analyzing crater elevation profiles. The process involves one of the following two approaches. The first uses scaling relationships to fit crater elevation profiles by regression and then the analysis of the fitting parameters is used to estimate and classify topographic changes across crater populations [2]. The second approach fits the radial elevation variation of a crater to an arbitrary rational or irrational polynomial function [3]. For both the above-mentioned processes – fitting to an arbitrary, need specific model, is involved.

Instead of data fitting to an arbitrary model, we choose to approximate the topographic profile for a crater (thus avoiding a model mismatch) by the Chebyshev approximation process. Using the approximated profile, we show that the slope, rim sharpness and the nature of topographic variation (defection points along the radial profile) can be analyzed automatically and efficiently based on the approximation coefficients, leading to an understanding of the degradation process. Topographic data from the Lunar Reconnaissance Orbiter (LRO) Narrow Angle Camera digital elevation model (DEM) [4] and the LRO Wide Angle Camera global DEM [5] is used to describe our results. Craters

(diameters from 500 m to 5 km) from the same geologic unit are examined and compared .

References:

[1] Mahanti, P., et al., Icarus (2014). Volume 241, October 2014, Pages 114–129

[2] Pike, R., 1977b. Impact and Explosion Cratering: Planetary and Terrestrial Implications, vol. 1, pp. 489–509.

[3] R.A. Craddock, A.D. Howard, JGR.: Planets (1991–2012), 105 (E8) (2000), pp. 20387–20401

[4] Tran, T et al., Special Joint Symposium of ISPRS Technical Commission IV and AutoCarto, pp. 15–19.

[5] F. Scholten, et al.,JGR., 117 (2012), p. E00H17