Automatic Recognition of Impact Craters on the Martian Surface from DEM and Images - Planetary Exploration and Science: Recent Results and Advances - page 98

or lunar like, transitional, or diverse) (Barlow et al. 2003 ). Previous investigations
of the history of surface modification are based on crater morphology because the
impact craters are the only surface feature with initial known shape, which is one of
the most direct and effective approaches for human beings to better understand the
planets.
Another important and possible application of crater recognition is for a space-
craft to choose a landing site (Leroy et al. 2001 ). The spacecraft pose is always
refined for safe landing using conspicuous landmarks, such as craters, observed by
a visual sensor. It is very necessary to propose a robust method to detect craters
quickly and effectively. The detected craters in the image are matched with the
existing catalogue in order to avoid the uneven or hilly sites corresponding to the
craters.
All the previous studies on craters are based on the specific and reliable catalogue
of craters. Several teams aim to assemble as complete a global catalogue of Martian
impact craters as possible. It is laborious and complicated to construct a useful
catalogue (Barlow 1988 ; Stepinski et al. 2009 ; Salamuniccar et al. 2011 ). The
MA130301GT is one of the most complete and specific Martian crater catalogues
constructed by Salamuniccar et al. ( 2011 ), which contains the major currently
available manually assembled catalogues and the automatically detected catalogues.
This catalogue has already integrated all the attributes available in the old catalogue
(Barlow, Rodionova, Boyce, Kuzmin, Stepinski). MA130301GT provides these
catalogues with (1) the correlation between various morphological descriptors
from used catalogues; (2) the correlation between manually assigned attributes
and automated depth/diameter measurements from MA75919T and our CDA; (3)
global surface dating; (4) average errors and their standard deviations for manually
and automatically assigned attributes, such as position coordinates, diameters, and
depth/diameter ratios; and (5) positional accuracy of features in the used datasets
according to the defined coordinate system referred to as Mars Global Digital Image
Mosaic MDIM 2.1, which incorporates 1,232 globally distributed ground control
points, while our catalogue contains 130,301 cross-references between each used
dataset. There is a considerable improvement in comparison with the completeness
of the Rodionova ( 10 km), Barlow ( 5km),andStepinski( 3 km) catalogues.
It is fundamental to develop an effective crater-detection algorithm (CDA) to
construct the crater catalogue. Salamuniccar and Loncari´c( 2012 ) reported that there
were 82 optical-based CDAs, 39 DEMs (Digital Elevation Maps) based on CDAs,
16 CDAs that could utilize both optical and DEM images, and only 3 CDAs from
other types of images. Fifty-nine percent CDAs are optically based because most
of the available images are optical ones. The second largest group of CDAs is
DEM based (28 %). The reason is that it is easier to develop a CDA for DEM
data, wherein issues like the position of the Sun, spacecraft, and the lunar/planetary
body are irrelevant. Changes in these values cause the changes in light direction and
extent of shadows and therefore make a development of optical-based CDAs more
challenging. A development of universal CDAs, which can process optical images
as well as DEMs, is even more challenging because algorithms applicable to the
first type of images are usually not applicable to the second type and vice versa.