Master student’s work placement offer-Bio-inspired solar tracking system for estimating the sun’s position using polarimetric analysis

Key words: polarisation pattern, UV/Visible camera, optical bench, solar position, solar tracker, bioinspiration.

This internship is part of the POLAR project. It aims to develop a collaboration between the Institut des Sciences du Mouvement (ISM) in Marseille (Luminy campus) and the Laboratoire d’Optique Atmosphérique (LOA) in Villeneuve d’Ascq. This project will involve estimating the position of the sun from the pattern of polarised light in the sky in the Visible/UV spectral bands for the purposes of atmospheric observations. Studies have shown that certain animals, such as insects like the desert ant Cataglyphis, use the polarisation pattern of the sky in the ultraviolet band (350 nm) to find their heading. We

have recently developed an experimental set‐up using two polarimetric cameras: a polarimetric camera sensitive to visible radiation and a camera

sensitive to UV radiation equipped with a rotating polarised filter driven by a stepper motor (Fig. 1). The advantage of using two cameras (one UV and the

other visible) will be to show that it is possible to estimate the position of the sun, even on overcast days. The aim of the course will be to calibrate this pair

Figure 1. Experimental bench. See [1].

of cameras, then to estimate the position of the sun by merging the optical information from the different types of images (intensity, polarisation angle, degree of polarisation). The aim is to prove not only the value of measuring different types of radiation, but also the value of fusing optical data to significantly improve the estimation of the sun’s position, whatever the cloud cover. By estimating the position of the sun relative to the camera frame of reference, the PLASMA photometer head can be aimed at the sun or at a point in the sky for atmospheric measurements and aerosol characterisation.

Duration: 5~6 months from February 2025

Address: Institut des Sciences du Mouvement – Etienne‐Jules Marey, Equipe Systèmes Bio‐Inspirés, 163 Avenue de Luminy, 13009 Marseille, France (South of France). At the heart of the Calanques National Park of Marseille.

Net gratuity: €670 per month (regulatory minimum set at €4.35 per hour in 2025 in France)

Profile required:

Engineering school or specialised master’s degree

Knowledge of optics, instrumentation, analogue electronics and image processing, A taste for experimentation and modelling,

Python programming

Knowledge of deep learning and the Tensorflow tool would be a plus Good level of English

Please send a CV, covering letter and Master’s transcripts to:

Supervision:

Prof. Julien Serres, University Professor AMU, ISM, https://serres‐lab.com/

Dr. Stéphane Viollet, CNRS Research Director, ISM, https://www.biorobotique.fr/

Collaborator:

Dr. Luc BLAREL, R&D Engineer, LOA Laboratory, PHOTONS/AERONET observation service, University of Lille, North of France, who will be monitoring the POLAR project and sharing his technical and scientific expertise in order to integrate the POLAR observation instrument into the LOA laboratory.

Application to be sent to: julien.serres@univ‐amu.fr and stephane.viollet@univ‐amu.fr

¹ Moutenet, A., Serres, J., & Viollet, S. (2023, October). Ultraviolet vs. Visible Skylight Polarization Measurements. In IEEE Sensors 2023. IEEE. https://hal.science/hal‐04267719/