Sebastian Walter

Freie Universität Berlin | FUB · Institute of Geological Sciences

After more than ten years in orbit at Mars, the coverage from the High Resolution Stereo Camera (HRSC) on the European Space Agency’s Mars Express is sufficient to begin constructing mosaic products on a global scale. We describe our systematic processing procedure and, in particular, the technique used to bring images affected by atmospheric dust...

Web-based planetary image dissemination platforms usually show outline coverage of available data and offer querying for metadata as well as preview and download. While the usual form of presenting multiorbit data sets is to merge the data into a larger mosaic, for change detection purposes it is essential to maintain the individual images as an im...

Perseverance’s Mastcam-Z instrument provides high-resolution stereo and multispectral images with a unique combination of spatial resolution, spatial coverage, and wavelength coverage along the rover’s traverse in Jezero crater, Mars. Images reveal rocks consistent with an igneous (including volcanic and/or volcaniclastic) and/or impactite origin a...

Perseverance's Mastcam-Z instrument provides high-resolution stereo and multispectral images with a unique combination of spatial resolution, spatial coverage, and wavelength coverage along the rover's traverse in Jezero crater, Mars. Images reveal rocks consistent with an igneous (including volcanic and/or volcaniclastic) and/or impactite origin a...

Spaceborne impact ionization mass spectrometers, such as the Cosmic Dust Analyzer on board the past Cassini spacecraft or the SUrface Dust Analyzer being built for NASA's upcoming Europa Clipper mission, are of crucial importance for the exploration of icy moons in the Solar System, such as Saturn's moon Enceladus or Jupiter's moon Europa. For the...

Since 2003 the High Resolution Stereo Camera (HRSC) experiment on Mars Express is in orbit around Mars. Besides the obligatory “Earth Farewell” and “Mars Approach” releases, created during transit of the spacecraft, the first surface-images were sent to Earth on January 14th 2004. On January 19th these images were released featuring Hydraotes Chaos...

We provide an overview of quality characteristics of the regional data products of the HRSC Mars Chart (HMC-30) series, and present new data on coordinate accuracy relative to the MOLA global reference, which were not available from previous HRSC DTMs. Finally, details of the HMC-30 global map layout and tiling scheme are reported.

Virtual Observatory tools are specifically designed for astronomical data, but they can be adapted to work with geospatial data by providing existing Geographical Information System tools with Simple Application Messaging Protocol interface. Open source QGIS package was chosen as a platform for this. The Simple Application Messaging Protocol interf...

The first high-resolution Digital Terrain Model (DTM) of the entire South Pole of Mars has been produced. A modified version (Kim and Muller, 2009) of a NASA-VICAR-based pipeline developed by DLR (German Aerospace Centre) and JPL (Jet Propulsion Laboratory) has been employed with image matching based on the Gotcha (Gruen-Otto-Chau) algorithm (Shin...

The 90.5-km Occator crater, with its peculiar and unique bright spots, is one of the most prominent and renowned feature on Ceres. Occator attracted broad public attention in scientific media as it is proposed to exhibit signs of post-impact cryovolcanic activity. In order to understand the time sequence of deposition, several attempts were made du...

Digital Terrain Model (DTM) creation is essential to improving our understanding of the formation processes of the Martian surface. Although there have been previous demonstrations of open-source or commercial planetary 3D reconstruction software, planetary scientists are still struggling with creating good quality DTMs that meet their science need...

This work presents the coregistered, orthorecti�ed and mosaiced high-resolution products of the MC11 quadrangle of Mars, which have been processed using novel, fully automatic, techniques. We discuss the development of a pipeline that achieves fully automatic and parameter independent geometric alignment of high-resolution planetary images, startin...

There has been a revolution in 3D surface imaging of Mars over the last 12 years with systematic stereoscopy from HRSC. Digital Terrain Models (DTMs) and OrthoRectified Images (ORIs) have been produced for almost 50% of the Martian surface. DLR, together with the HRSC science team, produced 3D HRSC mosaic products for large regions comprising aroun...

There has been a revolution in 3D surface imaging of Mars over the last 12 years with systematic stereoscopy from HRSC and the production for almost 50% of the Martian surface of DTMs and ORIs. The iMars project has been exploiting this unique set of 3D products as a basemap to co-register NASA imagery going back to the 1970s. DLR have produced 3D...

Understanding planetary atmosphere-surface and extra-terrestrial-surface formation processes within our Solar System is one of the fundamental goals of planetary science research. There has been a revolution in planetary surface observations over the last 15 years, especially in 3D imaging of surface shape. This has led to the ability to be able to...

Understanding planetary atmosphere-surface and extra-terrestrial-surface formation processes within our Solar System is one of the fundamental goals of planetary science research. There has been a revolution in planetary surface observations over the last 15 years, especially in 3D imaging of surface shape. This has led to the ability to be able to...

Understanding planetary atmosphere-surface exchange and extra-terrestrial-surface formation processes within our Solar System is one of the fundamental goals of planetary science research. There has been a revolution in planetary surface observations over the last 15 years, especially in 3D imaging of surface shape. This has led to the ability to o...

Understanding planetary atmosphere-surface exchange and extra-terrestrial-surface formation processes within our Solar System is one of the fundamental goals of planetary science research. There has been a revolution in planetary surface observations over the last 15 years, especially in 3D imaging of surface shape. This has led to the ability to o...

The High Resolution Stereo Camera (HRSC) of ESA's Mars Express is designed to map and investigate the topography of Mars. The camera, in particular its Super Resolution Channel (SRC), also obtains images of Phobos and Deimos on a regular basis. As HRSC is a push broom scanning instrument with nine CCD line detectors mounted in parallel, its unique...

We present a new online database for quick and easy access to already published HRSC-based geological mappings on Mars.

Understanding the role of different solid surface formation processes within our Solar System is one of the fundamental goals of planetary science research. There has been a revolution in planetary surface observations over the last 8 years, especially in 3D imaging of surface shape (down to resolutions of 10s of cms) and subsequent terrain correct...

Understanding the role of different planetary surface formation processes within our Solar System is one of the fundamental goals of planetary science research. There has been a revolution in planetary surface observations over the last 8 years, especially in 3D imaging of surface shape (down to resolutions of 10cm) and subsequent terrain correctio...

For global mosaicking of HRSC we present a first-order systematic photometric correction for the single image sequences based on a Lambertian reflectance model.

Introduction: Mars Express HRSC image strips show varying brightnesses caused by differing illumination and atmospheric conditions. Lambert correction improves the situation [1], but not sufficiently for a visually consistent mosaic (Fig 1).

Introduction: The High Resolution Stereo Camera (HRSC) on the Mars Express (MEx) orbiter has acquired 3640 images (with 'preliminary level 4' processing as described in [1]) of the Martian surface since arriving in orbit in 2003, covering over 90% of the planet [2]. At resolutions that can reach 10 me-ters/pixel, these MEx/HRSC images [3-4] are con...

We have performed extensive analyses of size-frequency distributions accumulated on ejecta blankets of 42 fresh primary craters on Vesta.

We have measured size-frequency distributions of sub-km impact craters on fresh units on Vesta and performed weighted least squares regression analyses. Derived power-law exponents were then compared with the two currently used production functions.

The High Resolution Stereo Camera (HRSC) is a push-broom image sensor onboard Mars Express recording the Martian surface in 3D and color. Being in orbit since 2004, the camera has obtained over 3,600 panchromatic image sequences covering about 70% of the planet's surface at 10-20 m/pixel. The composition of an homogenous global mosaic is a major ch...

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We derived model functions for the crater production size-frequency distribution and chronology of the asteroids 951 Gaspra, 243 Ida, 21 Lutetia and 4 Vesta, based on a lunar-like crater production function and a lunar-like chronology with a smooth exponential decay in impact rate for the first ~1 Ga of Solar System history. For Gaspra, Ida and Lut...

We discuss our approach toward automatically combining hundreds of the MarsExpress/HRSC panchromatic or color images together to construct a global mosaic.

We want to improve HRSC data dissemination for scientific analysis by a dynamic mapserver for data queries and data products compliant to geospatial standards.

We measured size-frequency distributions of small impact craters on the protoplanet Vesta to investigate probabilities of contamination by secondary craters.

We have completed a new 1:3,000,000 geomorphologic map of Tempe Terra along with parts of sorrounding units of Kasei Valles, Tharsis, and Arcadia Planitia.

(abridged) We describe an image-comparison technique of Heidemann and Ritter that uses image compression, and is capable of: (i) detecting novel textures in a series of images, as well as of: (ii) alerting the user to the similarity of a new image to a previously-observed texture. This image-comparison technique has been implemented and tested usin...

We discuss our approach towards automatically mosaicking hundreds of the HRSC panchromatic or RGB images together. Our best results consist of adding a high-pass-filtered HRSC mosaic to a low-pass-filtered OMEGA global mosaic.

The High Resolution Stereo Camera (HRSC) on the Mars Express (MEx) orbiter has acquired 3640 images (with 'preliminary level 4' processing as described in [1]) of the Martian surface since arriving in orbit in 2003, covering over 90% of the planet [2]. At resolutions that can reach 10 meters/pixel, these MEx/HRSC images [3-4] are constructed in a p...

Planetary Sciences teach us how special our homeplanet is in the solar system. Incorporating a broad variety of natural science topics they count to the most fundamental branches of scientific research with a strong interdisciplinary character. However, since planetary sciences are not a school subject, children as well as adults are often lacking...

At the Planetary Sciences and Remote Sensing Group of Freie Universitaet Berlin we have set up a map server for dynamic data queries of the High Resolution Stereo Camera (HRSC, [1, 2]). Various preprocessed image data products, converted to common raster formats (GeoTiff and GeoJP2000), are provided for download from within the web interface. The H...

http://meetingorganizer.copernicus.org/EPSC2013/EPSC2013-990.pdf

We investigated prominent impact features in the mapping quadrangle Av-13 Tuccia, as this quadrangle offers a rich variety of different crater morphologies.

We want to use the bundle adjusted orientation information of the High Resolution Stereo Camera (HRSC) together with the terrain model to derive an empirical photometric model of the image and use it for eliminating the topographic shading effects.

In a systematic approach, we want to use the exact orientation information of an image sequence of the High Resolution Stereo Camera (HRSC, [1], [2]) to derive a synthetic photometric model and compare it with the recorded HRSC image. This model can serve for several purposes, one of which would be the isolation of albedo features from the topograp...

We want to use orientation information of HRSC and the surface to derive a photometric model and compare it with the HRSC image. This model can then be used for several purposes, e.g. to correct the acquired image to standard lighting geometry.

We describe an image-compression technique of Heidemann and Ritter [4] that is capable of: (i) de-tecting novel textures in a series of images, as well as of: (ii) alerting the user to the similarity of a new image to a previously-observed texture. This image-compression technique has been implemented and tested using our Astrobiology phone-cam sys...

Data sets, acquired from Mars during several missions have provided detailed data for a better understanding of the evolution of the Tharsis Region in particular the origin of the Tharsis Montes. The High Resolution Stereo Camera (HRSC) on board of the ESA Mars Express Orbiter provided high-resolution color and stereo image data of the Tharsis Mont...

Correction of Shading Effects of HRSC Images using Photometric Models on Pixel-scale Surface Orientation

In this work, we present a new frontend for the existing data sets served by the Mars Mapserver prototype. This new frontend is based on the Open Source p.mapper/MapScript framework and includes improved functionality together with an advanced dynamic user interface.

Photometric correction routines of planetary image data are developed and implemented using the ArcGIS framework with which the assessment, quantification and correction of photometric effects can be improved in an efficient way on an end-user level.

We want to present our approach for the systematic correction of shading effects on level 4 HRSC imagery using simple and approved photometric models applied on the real surface orientation derived by the associated HRSC-DTM.

Herein we present a computer vision algorithm, based in part on an artificial neural network capable of identifying novel, previously unseen areas of geological or astrobiological scenery.

(ABRIDGED) In previous work, two platforms have been developed for testing computer-vision algorithms for robotic planetary exploration (McGuire et al. 2004b,2005; Bartolo et al. 2007). The wearable-computer platform has been tested at geological and astrobiological field sites in Spain (Rivas Vaciamadrid and Riba de Santiuste), and the phone-camer...

We will demonstrate techniques to exemplary deliver image and footprint data of the two instruments HRSC/SRC and OMEGA onboard ESA's Mars Express Orbiter. The aim here is to use open source software and comply to standards defined by the Open Geospatial Consortium (OGC). There are two interesting services defined by the OGC which are well suited fo...

We will demonstrate techniques to deliver HRSC and SRC image data as well as OMEGA footprint data based on standards defined by the Open Geospatial Consortium (OGC) using open source software.

HRSCview provides a rapid online means to explore Mars Express HRSC images. It is a joint website of the Free University of Berlin and the German Aerospace Center (DLR) and can be visited at http://hrscview.fu-berlin.de (Source: http://adsabs.harvard.edu/abs/2008LPI....39.1822M):

HRSCview provides a rapid online means to explore Mars Express HRSC images. It is a joint website of the Free University of Berlin and the German Aerospace Center (DLR) and can be visited at http://hrscview.fu-berlin.de.

The High Resolution Stereo Camera (HRSC) on the ESA Mars Express spacecraft has been orbiting Mars since January 2004. By spring 2007 it had returned around 2 terabytes of image data, covering around 35% of the Martian surface in stereo and colour at a resolu-tion of 10-20 m/pixel. HRSCview provides a rapid means to explore these images up to their...

Being in its fourth year of operation, the HRSC/SRC instrument onboard ESA's Mars Express orbiter has acquired over 1400 images in colour and stereo during nearly 4500 orbits around the red planet. Approximately two thirds of the surface has been covered in a resolution of at least 200m per pixel. As the amount is rising, there is a fundamental nee...

To increase the usability and accessibility of the very large HRSC dataset to the science community we have implemented a system for exploring the data via the web, with linked access to full archived science data products.

The geometric outline of remote sensing image data, the so called footprint, can be represented as a number of coordinate tuples. These polygons are associated with according attribute information such as orbit name, ground- and image resolution, solar longitude and illumination conditions to generate a powerful base for classification of planetary...

To increase the usability and accessibility of the now very large Mars Express HRSC colour stereo image dataset (now exceeding 2 TB map-projected) to the science community we have implemented a system for exploring the data via the web, and providing access to download the full map-projected science dataproducts. The system may be accessed using a...