Preparation of the ExoMars Mission: Feasibility study and preliminary methods for generating stereoscopic data with the CLose-UP Imager CLUPI

The CLose-UP Imager (CLUPI) onboard the ESA ExoMars rover is a camera system that will be used for capturing high-resolution images of Martian rocks and soil. The goal of this study was to define a method based on the Structure-from-Motion (SfM) that allows for generating stereoscopic and three-dimensional data from CLUPI images. Although CLUPI is a mono-optic camera, we were able to identify the ideal CLUPI positioning and calculate the rover movements necessary for acquiring images in a given rover position that we subsequently processed to produce stereoscopic photographs and derive 3D and topographical data with Agisoft. To perform this feasibility test in our laboratory, using the EM+, a CLUPI representative engineering model, the 3D and topographical reconstruction was based on a translation of the rover, on the ”close-up outcrop observation” configuration in a fixed drill position. The two acquired images, one before and one after the rover’s translation are the stereo pairs needed to perform the digital outcrop model (DOM) reconstruction. By importing the data into Geographic Information System (GIS) software, we generated maps, profiles, and stream maps, which enable a detailed characterization of rock textures and sedimentary structures (e.g., clast and phenocryst shape, size, and distribution, laminations thickness and angular relationships…). This study proposes a method easily reusable for creating 3D and stereo data with CLUPI images.