engleski

Method for crater detection from digital topography data: interpolation based improvement and application to Lunar SELENE LALT data

Crater detection algorithms (CDAs) are an important subject of recent scientific research, as evident from the numerous recent publications in the field [ASR, 42 (1), 6-19]. In our previous work: (1) all the craters from the major currently available manually assembled catalogues have been merged into the catalogue with 57633 known Martian impact-craters [PSS, 56 (15), 1992-2008] ; and (2) the CDA (developed to search for still uncatalogued impact-craters using 1/128$^\circ$ MOLA data) has been used to extend GT-57633 catalogue with 57592 additional craters resulting in GT-115225 catalog [GRS, 48 (5), in press, doi:10.1109/TGRS.2009.2037750]. On the other hand, the most complete catalog for Moon is the Morphological catalog of Lunar craters [edited by V. V. Shevchenko], which includes information on 14923 craters larger than 10km, visible on the lunar nearside and farside. This was the main motivation for application of our CDA to newly available Lunar SELENE LALT data. However, one of the main differences between MOLA and LALT data is the highest available resolution, wherein MOLA is available in 1/128$^\circ$ and LALT in 1/16$^\circ$. The consequence is that only the largest craters can be detected using LALT dataset. However, this is still an excellent opportunity for further work on CDA in order to prepare it for forthcoming LRO LOLA data (which is expected to be in even better resolution than MOLA). The importance is in the fact that morphologically Martian and Lunar craters are not the same. Therefore, it is important to use the dataset for Moon in order to work on the CDA which is meant for detection of Lunar craters as well. In order to overcome the problem of currently available topography data in low resolution only, we particularly concentrated our work on the CDA’s capability to detect very small craters relative to available dataset (up to the extreme case wherein the radius is as small as only two pixels). For this purpose, we improved the previous CDA with a new algorithm for sub-pixel interpolation of elevation samples, before subsequent computations. For elevation samples on larger distances from the crater’s center, linear interpolation was used in order to speed-up the computations. For samples closer to the crater’s center, the elevation value at the crater’s center and relative sub-pixel distance to the selected elevation sample is additionally taken into account. The purpose is to compute the most realistic values for estimated elevation at a selected point. The results are, according to the initial visual evaluation, that numerous craters were successfully detected using SELENE LALT data.

Moon; crater detection

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