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3D Digital Reconstruction of the Kimberley Outcrop (Gale Crater, Mars) from Photogrammetry using Multi-Scale Imagery from Mars Science Laboratory
Gwénaël Caravaca, Stéphane Le Mouélic, Nicolas Mangold, Jonas l’Haridon, Laetitia Le Deit, Marion Massé
To cite this version:
Gwénaël Caravaca, Stéphane Le Mouélic, Nicolas Mangold, Jonas l’Haridon, Laetitia Le Deit, et al.. 3D Digital Reconstruction of the Kimberley Outcrop (Gale Crater, Mars) from Photogram-metry using Multi-Scale Imagery from Mars Science Laboratory. 50th Lunar and Planetary Sci-ence ConferSci-ence 2019, Mar 2019, The Woodlands, United States. 179, pp.300 - 314, 2012, �10.13140/RG.2.2.19734.57929�. �hal-02882363�
Introduction:
Structure-from-Motion (SfM) photogrammetry is an efficient, low-cost and powerful method to reconstruct Digital Outcrop Models (DOM) based only on a set of photos [1]. This method is particularly well-suited in
remote planetary exploration such as that of Gale Crater, Mars, using extensive imagery data from the Mars Science Laboratory (MSL) rover Curiosity [2].
Using a set of multi-scale images photos from 3 different instruments aboard Curiosity, we were able to compute a high-resolution and highly-detailed full color DOM of the Kimberley outcrop (sols 603-630). This model
has then been integrated into a Virtual Reality (VR) environment for visualization and “in situ” geological characterization.
3D digital reconstruction of the Kimberley outcrop (Gale Crater, Mars) from photogrammetry
using multi-scale imagery from Mars Science Laboratory
Gwénaël Caravaca*
1, Stéphane Le Mouélic
1, Nicolas Mangold
1, Jonas L’Haridon
1, Laetitia Le Deit
1, Marion Massé
1*Corresponding author; gwenael.caravaca@univ-nantes.fr 1
Laboratoire de Planétologie et Géodynamique, UMR 6112 CNRS, Université de Nantes, Université d’Angers, 2 Rue de la Houssinière, 44322 Nantes Cedex 3, France
Photogrammetry using Structure-from-Motion:
SfM photogrammetry allows to reconstruct a DOM from only a set of
overlapping photos [1, 2]. The process consists in:
• Analysis and alignment of overlapping photos
• Recognition of tie-points across the photoset
• Projection of tie-points within a 3D space into a scarce/dense point cloud
• Triangulation of the points to create a grid or “3D mesh”
• Colorization and/or texturing of the mesh
Here we use Agisoft PhotoScan Professional software to perform SfM photogrammetry
Perspectives for the geological analysis of the multiscale Kimberley DOM
The Kimberley DOM was integrated into a Virtual Reality environment, allowing one or several networked users:
• Visualization and exploration of the model at real-scale, and contextualization of the sampling targets (e.g. Windjana drill)
• Accurate characterization and mapping of the various geological features without deformation
The Kimberley area presents poorly constrained stratigraphic relations though they are critical to the signification of the local unusually high potassic accumulations [5]. Therefore, the integration of the Kimberley DOM into VR allows a
new and more accurate geological “in situ” analysis of the outcrop, leading to new understandings of the local to
regional paleoenvironments.
Reconstruction of reliable photorealistic DOM using photogrammetry and their integration within a VR
environment opens the way for future exploration of remote Martian outcrops. Forthcoming work will be dedicated
to the development of measurement tools to be used directly in VR (e.g. compass, clinometer, distance meter, etc.)
a) “Selfie” of Curiosity taken by the MAHLI camera, showing the position of both right and left MastCam (MR, ML) and NavCam. b) Composite image showing the variations in resolution, colorization and field of view of the different NavCam and MastCam cameras (MR and ML)
Reconstruction of the Kimberley Digital Outcrop Model:
The Kimberley DOM was reconstructed using 530 NavCam and 1443 MastCam georeferenced photos available on the public Planetary Data System servers [4].
These multi-scale data (mm– to pluri-meter-scale) are used to reconstruct a highly-resolved, full color DOM, covering a surface of ~1670 m². Georeferenced source material also allows to obtain a geographically constrained and scaled 3D model.
A 3D model of the Windjana drill was also reconstructed using 32 MAHLI photos to provide a sub-mm-scale additional level of detail to the DOM.
Processing multi-scale data:
Curiosity is equipped with different cameras such as:
• The navigational cameras (NavCam): a pair of greyscale
stereoscopic cameras.
• The left and right mast cameras (MastCam): full color camera
with different focal lengths (ML: 34 mm, MR: 100 mm).
• The Mars Hand Lens Imager (MAHLI): a full color microscope.
Those cameras have different resolutions and focal lengths, resulting in poor overlapping between successive photos [3], preventing a direct use for SfM photogrammetry, except for the NavCam.
Our objective is to integrate all the photos taken at Kimberley using these three cameras to reconstruct a multi-scale DOM with higher accuracy and greater details for geological analysis.
Acknowledgments:
This work is part of a project that has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement Nº776276 (PLANMAP)References:
[1] Westoby M.J. et al. (2012) Geomorphology, 179, 300-314. [2] Ostwald A.M. & Hurtado J.M. Jr. (2017) LPS XLVIII, Abstract #1787. [3] Alexander, D., Deen, R. (2015) Mars Science Laboratory Project Software Interface Specification,
Version 3.5. [4] Planetary Data System archive node, https://pds-imaging.jpl.nasa.gov/portal/msl_mission.html [5]
Le Deit et al. (2016) J. Geophys. Res. Planets, 121, 784-804.
a) Interpreted VR panorama of
the Kimberley stratigraphic series
(after [5]).
b) Two VR users are exploring the
Kimberley outcrop.
c) Close-up of the very
high-resolution MAHLI mesh of the
Windjana drill. The sub-mm-scale
resolution of the model allows to
observe the marks left by
Chem-Cam’s Laser-Induced Breakdown
Spectroscopy instrument (LIBS;
<1 mm).
a) Georeferenced photos are automatically positioned within
PhotoScan reproducing the
actual traverse of Curiosity
b) Scarce point cloud generated
using tie-points recognized
across the 530 aligned NavCam photos
c) Dense point cloud generated using the 530 aligned NavCam photos. The dense point cloud allows to observe the general shape of the Kimberley outcrop
d) Dense point cloud generated using the 530 NavCam photos AND the 1443 MastCam photos. These latter are aligned based on the previously-computed position of the 530 NavCam
e) Low-resolution greyscale
DOM triangulated from the NavCam only dense cloud (c). This DOM shows a restricted level of detail and accuracy (dm-scale)
f) High-resolution full color DOM triangulated from the NavCam + MastCam dense cloud (d). This DOM shows a very high level of detail and accuracy (up to sub-cm-scale). The textures have been computed using MastCam photos only
