[Show abstract][Hide abstract] ABSTRACT: A Digital Terrain Model (DTM) of the Taurus-Littrow Valley with a 1.5 m/pixel resolution was derived from high resolution stereo images of the Lunar Reconnaissance Orbiter Narrow Angle Camera (LROC NAC) . It was used to create a controlled LROC NAC ortho-mosaic with a pixel size of 0.5 m on the ground. Covering the entire Apollo 17 exploration site, it allows for determining accurate astronaut and surface feature positions along the astronauts' traverses when integrating historic Apollo surface photography to our analysis.
[Show abstract][Hide abstract] ABSTRACT: We are engaged in a comprehensive analysis of lu-nar/planetary dynamics to provide updated reference frames for deep space navigation and Lunar explo-ration. On the basis of Lunar Laser ranging data, we have updated the Earth-Moon ephemeris as well as the Lunar rotation model and reference frame. We use ranging and radio tracking data to the LRO space-craft as well as numerical integrations in the GRAIL-derived Lunar gravity field to firmly tie the LRO orbit into the Lunar-fixed reference frame. We demonstrate for the Apollo 15 site that images and Laser altimeter data taken by the LRO can be firmly tied to our Lunar reference frame using Lunar Laser Reflector stations as control points.
[Show abstract][Hide abstract] ABSTRACT: We have derived algorithms and techniques to precisely co-register laser altimeter profiles with gridded Digital Terrain Models (DTMs), typically derived from stereo images. The algorithm consists of an initial grid search followed by a least-squares matching and yields the translation parameters at sub-pixel level needed to align the DTM and the laser profiles in 3D space. This software tool was primarily developed and tested for co-registration of laser profiles from the Lunar Orbiter Laser Altimeter (LOLA) with DTMs derived from the Lunar Reconnaissance Orbiter (LRO) Narrow Angle Camera (NAC) stereo images. Data sets can be co-registered with positional accuracy between 0.13 m and several meters depending on the pixel resolution and amount of laser shots, where rough surfaces typically result in more accurate co-registrations. Residual heights of the data sets are as small as 0.18 m. The software can be used to identify instrument misalignment, orbit errors, pointing jitter, or problems associated with reference frames being used. Also, assessments of DTM effective resolutions can be obtained. From the correct position between the two data sets, comparisons of surface morphology and roughness can be made at laser footprint- or DTM pixel-level. The precise co-registration allows us to carry out joint analysis of the data sets and ultimately to derive merged high-quality data products. Examples of matching other planetary data sets, like LOLA with LRO Wide Angle Camera (WAC) DTMs or Mars Orbiter Laser Altimeter (MOLA) with stereo models from the High Resolution Stereo Camera (HRSC) as well as Mercury Laser Altimeter (MLA) with Mercury Dual Imaging System (MDIS) are shown to demonstrate the broad science applications of the software tool.
No preview · Article · Dec 2013 · Planetary and Space Science
[Show abstract][Hide abstract] ABSTRACT: We have derived a stereo-topographic model and an orthoimage mosaic
based on Lunar Reconnaissance Orbiter (LRO) Narrow Angle Camera (NAC)
images to study the Luna-17 landing site. In the images (0.33-0.5
m/pixel), the Lunokhod-1, the Luna-17 landed spacecraft, and the rover
tracks can clearly be identified and mapped for 99% of the traverse. The
traverse was found to be 9.93 km long, approximately 0.50 km shorter
over what had been estimated earlier (10.54 km). The total topographic
relief along the traverse was found to be within 26 m. Along its
traverse, the rover encountered slopes of up to 5°, estimated over
2.5 m baselength. By comparison with previously published topographic
maps and using our orthomosaic as a reference (which had been tied to
the well-known Lunokhod-1 Laser reflector coordinates), we report on
coordinates of Lunokhod-1's panorama points and overnight stops.
Comparisons of currently mapped tracks with previous traverse
reconstructions show good matches on small scale, but reveal that
previous maps had long-wavelength geometric distortions of up to 100-m
level. Agreement in topographic trends was very limited.
No preview · Article · Sep 2013 · Planetary and Space Science
[Show abstract][Hide abstract] ABSTRACT: To support reanalysis of the Apollo 17 seismic data we determined the
ME-coordinates of the LSPE active sources and receivers using LROC NAC
and Apollo surface images.
[Show abstract][Hide abstract] ABSTRACT: A method to improve LOLA DTMs with the help of NAC DTMs is shown at
Connecting Ridge, a candidate landing site for the ESA Lunar Lander at
the lunar south pole.
[Show abstract][Hide abstract] ABSTRACT: Accurate coordinates of the Apollo Lunar Surface Experiment Package
(ALSEP) instruments were determined by an integrated analysis of Apollo
17 surface photography and Lunar Reconnaissance Orbiter Camera (LROC)
images. Angular measurements made in the surface images were fitted to
an LROC Narrow Angle Camera (NAC) orthoimage (0.25 m pixel scale) by
least-squares techniques. We obtained camera and ALSEP instrument
positions with respect to the lunar fixed Mean Earth/Polar Axis (ME)
reference system. Coordinate accuracies were assessed to be within one
LROC NAC pixel.
[Show abstract][Hide abstract] ABSTRACT: Newly acquired high resolution Lunar Reconnaissance Orbiter Camera
(LROC) images allow accurate determination of the coordinates of Apollo
hardware, sampling stations, and photographic viewpoints. In particular,
the positions from where the Apollo 17 astronauts recorded panoramic
image series, at the so-called “traverse stations”, were
precisely determined for traverse path reconstruction. We analyzed
observations made in Apollo surface photography as well as
orthorectified orbital images (0.5 m/pixel) and Digital Terrain
Models (DTMs) (1.5 m/pixel and 100 m/pixel) derived from LROC
Narrow Angle Camera (NAC) and Wide Angle Camera (WAC) images. Key
features captured in the Apollo panoramic sequences were identified in
LROC NAC orthoimages. Angular directions of these features were measured
in the panoramic images and fitted to the NAC orthoimage by applying
least squares techniques. As a result, we obtained the surface panoramic
camera positions to within 50 cm. At the same time, the camera
orientations, North azimuth angles and distances to nearby features of
interest were also determined. Here, initial results are shown for
traverse station 1 (northwest of Steno Crater) as well as the Apollo
Lunar Surface Experiment Package (ALSEP) area.
Preview · Article · May 2012 · Journal of Geophysical Research Atmospheres
[Show abstract][Hide abstract] ABSTRACT: MIIGAiK is developing an automated GIS-oriented mapping technology for studies of planetary surfaces. Here we present the results of the Luna-17 Landing Site GIS mapping. In our study we used the high resolution orthoimages and DEM, which were previously obtained at DLR from the photogrammetric processing of LRO (Lunar Reconnaissance Orbiter) NAC (Narrow Angle Camera) stereo images (07350_M150749234, 07351_M150756018) with spatial resolutions of 0.5 m/pixel. Both data sets were used for landing site area and Lunokhod-1 traverse GIS analyses. The work carried out may prepare us for searching and assessing future landing sites of the LUNA-GLOB and LUNA-RESOURCE missions.
[Show abstract][Hide abstract] ABSTRACT: We have carried out a search for degraded impact basins on the Moon using as a basis the near-global digital terrain model (GLD100), derived from LROC-WAC stereo images.
[Show abstract][Hide abstract] ABSTRACT: MIIGAiK is developing an automated GIS-oriented mapping technology for studies of planetary surfaces. Here we present the new results of the Luna-17 Landing Site large-scale mapping. In our study we used the high resolution orthoimages and DEM, which were previously obtained at DLR from the photogrammetric processing of LRO (Lunar Reconnaissance Orbiter) NAC (Narrow Angle Camera) stereo images (07350_M150749234, 07351_M150756018) with spatial resolutions of 0.5 m/pixel. Both data sets were used for landing site area and Lunokhod-1 traverse GIS analyses. The work carried out may prepare us for searching and assessing future landing sites of the LUNA-GLOB and LUNA-RESOURCE missions.
[Show abstract][Hide abstract] ABSTRACT: Lunar Orbiter Laser Altimeter (LOLA) tracks and Lu-
nar Reconnaissance Orbiter Camera (LROC) terrain
models are co-registered using rigorous least-squares
techniques. The precisely matched data allows us to
determine the alignment of the two instruments, to
identify offsets and erroneous trends between the two
topographic data sets, and ultimately to study surface
slopes and roughness in two dimensions.
[Show abstract][Hide abstract] ABSTRACT: DTM and orthoimage derivation from HRSC data is combined by matching in object space. Thus, interconnections between these surface models are implicitly regarded. The flexible approach is the basis for future BRDF integration (e.g. Hapke's model).
[Show abstract][Hide abstract] ABSTRACT: Zusammenfassung: Der Zeilenscanner High Resolution Stereo Camera (HRSC) an Bord des "Mars Express" Orbiters liefert dreidimensionale Farbbilder von unserem Nach- barplaneten. Insgesamt werden neun Kanäle - fünf panchromatische in Stereowinkeln von maximal 18,9° und vier Farbkanäle - in Bodenauflösungen bis 12 m/Pixel simultan aufgenommen. Auf Grund dessen sind die HRSC-Daten prädestiniert für die Ableitung Digitaler Geländemodelle (DGM) und farbiger Orthobilder. Im Gegensatz zur systematischen Prozessierung sämtlicher Bilddaten, die auf klassi- schem Image-Matching zwischen den Stereokanälen basiert, wurde im Rahmen der hier vorgestellten Arbeiten das Facetten-Stereosehen exemplarisch auf HRSC-Bilder ange- wendet. Das Facetten-Stereosehen ist ein flexibler Ansatz zur Bildinversion im Objekt- raum. Es ermöglicht die integrierte Bestimmung von DGM und Orthobild unter Berück- sichtigung der gesamten Bildinformation, d.h. sämtlicher aufgenommener Pixel. Der Al- gorithmus wurde für die HRSC auf Mars Express angepasst, in MATLAB implementiert und auf kleine Regionen der Mars-Oberfläche angewendet - die Größe eines Auswerte- gebiets liegt im Bereich weniger Kilometer; typische Eingangsbilder umfassen etwa 200x200 Pixel in drei Kanälen (die beiden äußeren Stereokanäle und der Nadirkanal der HRSC). Für diese Regionen wurden DGMs mit Stützstellen im Abstand von 200 m sowie Orthobilder mit 25 m/Pixel generiert. Der verwendete Ansatz sowie erste Ergebnisse dieser Arbeiten werden vorgestellt.
[Show abstract][Hide abstract] ABSTRACT: The High Resolution Stereo Camera (HRSC) on Mars Express covers the surface of our neighboring planet in full color and 3D. Altogether, nine channels are obtained in stereo angles between ±18.9°. These data sets are well suited to derive Digital Terrain Mo- dels (DTM) and, based on that, color orthoimages. Both, photogrammetric standard processing of HRSC data as well as alternative and/or supplementary approaches are usually based on image matching or shape-from-shading. In contrast to classical matching between images - and aiming for the combined derivation of orthoimage, DTM, and reflectance properties of the Martian surface - HRSC data are processed using the Facets Stereo Vision approach, which is a flexible method for matching in object space. Transfer functions connect the object surface (surfels) with corresponding pixels in each image; the entire image content is treated as observables. The unknowns, in particular an orthoimage (brightness values) and a DTM (height values), are estimated in a combined least squares adjustment with respect to spatially regular grids in object space, i.e. the facets. Thus, existing interconnections between these models are implicitly regarded. In this context, an indirect approach of Facets Stereo Vision is utilized for the processing of HRSC data. It is implemented with MATLAB and applied for small Martian regions with varying surface characteristics. Exemplarily, the results for a steep crater rim and a comparatively flat region are presented and judged.