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

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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 Conference 2019, Mar 2019, The Woodlands, United States. 179, pp.300 - 314, 2012, ￿10.13140/RG.2.2.19734.57929￿. ￿hal-02882363￿

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Gwénaël Caravaca*1, Stéphane Le Mouélic1 , Nicolas Mangold1, Jonas L’Haridon1, Laetitia Le Deit1, Marion Massé1 *Corresponding author; [email protected] 1Laboratoire de Planétologie et Géodynamique, UMR 6112 CNRS, Université de Nantes, Université d’Angers, 2 Rue de la Houssinière, 44322 Nantes Cedex 3, France

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.

Photogrammetry using Structure-from-Motion: Reconstruction of the Kimberley Digital Outcrop Model: SfM photogrammetry allows to reconstruct a DOM from only a set of The Kimberley DOM was reconstructed using 530 NavCam and 1443 MastCam georeferenced photos available on the public Planetary Data System servers [4]. overlapping photos [1, 2]. The process consists in: • Analysis and alignment of overlapping photos 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.

• Recognition of tie-points across the photoset Georeferenced source material also allows to obtain a geographically constrained and scaled 3D model.

• Projection of tie-points within a 3D space into a scarce/dense point cloud 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.

• Triangulation of the points to create a grid or “3D mesh” a) Georeferenced photos are • Colorization and/ortexturing of the mesh automatically positioned within PhotoScan reproducing the Here we use Agisoft PhotoScan Professional software to perform SfM actual traverse of Curiosity photogrammetry 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 Processing multi-scale data: allows to observe the general shape of the Kimberley outcrop Curiosity is equipped with different cameras such as:

• The navigational cameras (NavCam): a pair of greyscale stereoscopic cameras. d) Dense point cloud generated using the 530 NavCam photos • The left and right mast cameras (MastCam): full color camera AND the 1443 MastCam photos. with different focal lengths (ML: 34 mm, MR: 100 mm). These latter are aligned based • The Mars Hand Lens Imager (MAHLI): a full color microscope. on the previously-computed Those cameras have different resolutions and focal lengths, resulting position of the 530 NavCam in poor overlapping between successive photos [3], preventing a direct use for SfM photogrammetry, except for the NavCam.

e) Low-resolution greyscale Our objective is to integrate all the photos taken at Kimberley using DOM triangulated from the these three cameras to reconstruct a multi-scale DOM with higher NavCam only dense cloud (c). accuracy and greater details for geological analysis. 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 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 photos only NavCam and MastCam cameras (MR and ML)

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 mappingof 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 a) Interpreted VR panorama of to the development of measurement tools to be used directly in VR (e.g. compass, clinometer, distance meter, etc.) the Kimberley stratigraphic series (after [5]).

b) Two VR users are exploring the

Acknowledgments: This work is part of a project that has received funding from the European Union's Horizon Kimberley outcrop. 2020 research and innovation programme under grant agreement Nº776276 (PLANMAP) c) Close-up of the very high- resolution MAHLI mesh of the Windjana drill. The sub-mm-scale

References: resolution of the model allows to

[1] Westoby M.J. et al. (2012) Geomorphology, 179, 300-314. [2] Ostwald A.M. & Hurtado J.M. Jr. (2017) LPS XLVIII, observe the marks left by Chem-

Abstract #1787. [3] Alexander, D., Deen, R. (2015) Mars Science Laboratory Project Software Interface Specification, Cam’s Laser-Induced Breakdown

Version 3.5. [4] Planetary Data System archive node, https://pds-imaging.jpl.nasa.gov/portal/msl_mission.html [5] Spectroscopy instrument (LIBS;

Le Deit et al. (2016) J. Geophys. Res. Planets, 121, 784-804. <1 mm).