Optical-radar fusion for rip-channel detection from Sentinel data

Inria; Valbonne; Remote; EUR 6,700 - 10,000; Full time

Benefits offered by this job

Partial reimbursement of public travel

Teleworking possible

Health insurance

Training opportunities

Job summary

Inria Côte d’Azur recherche un stagiaire au sein de l’équipe EVERGREEN pour travailler sur la fusion optique–radar et la détection de rip-channels à partir des données Sentinel. Vous utiliserez des détecteurs inspirés de DETR et enrichirez le jeu de données BAISen2 avec Sentinel‑1 pour évaluer les gains apportés par la fusion SAR/optique.

Le stage implique la collecte et le prétraitement de données Sentinel, l’entraînement et l’évaluation de modèles, et une collaboration étroite avec le

Qualifications

• Master, ou équivalent, requis.
• Bonne maîtrise de Python et du deep learning.
• Connaissance en télédétection, vision par ordinateur et apprentissage automatique.
• Expérience en détection d’objets appréciée.
• Expérience avec les données SAR ou satellites serait un plus.

Responsibilities

• Lire la littérature sur la détection des rip-channels et la fusion SAR/optique.
• Collecter et prétraiter les données Sentinel-1 afin de les faire matcher avec BAISen2.
• Former et évaluer des détecteurs de type DETR sur Sentinel-1 seul et en comparaison avec Sentinel-2.
• Concevoir et mettre en place des stratégies de fusion optique–radar en PyTorch, en s’appuyant sur le code existant.
• Rapporter et résumer les résultats.

Skills

Python programming

Deep learning (PyTorch)

Remote sensing / ML / CV

Object detection experience

SAR / satellite data experience

Education

Master's degree or equivalent

Tools

PyTorch

Job description

Optical-radar fusion for rip-channel detection from Sentinel data

Level of qualifications required : Master's or equivalent

Fonction : Internship Research

About the research centre or Inria department

Inria is the French National Institute for Research in Digital Science, of which the Inria Côte d'Azur University Center is a part. With strong expertise in computer science and applied mathematics, the research projects of the Inria Côte d'Azur University Center cover all aspects of digital science and technology and generate innovation. Based mainly in Sophia Antipolis, but also in Nice and Montpellier, it brings together 47 research teams and nine support services. It is active in the fields of artificial intelligence, data science, IT system security, robotics, network engineering, natural risk prevention, ecological transition, digital biology, computational neuroscience, health data, and more. The Inria Center at Université Côte d'Azur is a major player in terms of scientific excellence, thanks to the results it has achieved and its collaborations at both European and international level.

Context

The internship position is opened in the context of the EVERGREEN team project - https://team.inria.fr/evergreen/ .

Our team is actively working on the design and implementation of cutting-edge machine learning techniques to effectively exploit heterogeneous and multi-temporal Earth observation data for agricultrual and enviromental applications.

The team, located in a multidisciplinary laboratory, has an active and stimulating environment with master, PhD and Post-doc students coming from different countries.

The internshipwill be funded by a project in collaboration with INRAE.

Assignment

Assignments : With the help of members of the EVERGREEN team (Cassio F. Dantas and Dino Ienco), the intern will add Sentinel-1 SAR data to an existing Sentinel-2 dataset for rip-channel detection (BAISen2), which was developed within the context of an ongoing PhD thesis in the team (Christopher Jabea). The intern will then assess what SAR imagery brings to the detection of rip channels along the French Atlantic coast, using deep learning detectors based on the DETR architecture and optical-radar fusion.

For a better knowledge of the proposed research subject :

Rip channels are deep incisions in surf-zone sandbars associated with rip currents, the leading cause of drowning on beaches worldwide [1]. Our team built BAISen2 [2], an open dataset of 2,058 Sentinel-2 patches with 12,504 bounding boxes. It covers 42 sites along 350 km of the French Atlantic coast from 2015 to 2024.

Optical imagery depends on daylight and cloud cover, but SAR does not, and rip-current signatures have already been seen in spaceborne SAR imagery [3]. The internship will address three questions:

• Are rip channels visible in Sentinel-1 imagery?
• How does a detector trained on Sentinel-1 alone compare with one trained on Sentinel-2?
• Does combining Sentinel-1 and Sentinel-2 improve detection [4]?

The team’s existing codebase for training and evaluating DETR‑like detectors will be extended to optical–radar fusion.

[1] B. Castelle, T. Scott, R. W. Brander, R. J. McCarroll. “Rip current types, circulation and hazard.” Earth-Science Reviews, 163:1–21, 2016.

[2] C. Jabea, J. Turpin, C. F. Dantas, B. Castelle, I. Manighetti, D. Ienco. “BAISen2: A Sentinel-2 image dataset for rip channels detection along the French Atlantic coast.” Zenodo, 2026. https://doi.org/10.5281/zenodo.21980065

[3] J. C. B. da Silva. “SAR observation of rip currents off the Portuguese coast.” In V. Barale et al. (eds.), Remote Sensing of the European Seas, pp. 399–410. Springer, 2008.

[4] A. Fuller, K. Millard, J. R. Green. “CROMA: Remote sensing representations with contrastive radar‑optical masked autoencoders.” NeurIPS, 2023.

Collaboration : The intern will work closely with Christopher Jabea, a PhD student in the EVERGREEN team who works on rip-channel detection from satellite imagery and is the lead author of the BAISen2 dataset

Main activities

Main activities :

• Review the scientific literature on rip-channel and rip-current detection, SAR imagery and optical–radar fusion.
• Collect and preprocess Sentinel‑1 SAR data that matches the BAISen2 dataset (same sites and acquisition dates).
• Train and evaluate DETR‑like detectors on Sentinel‑1 alone and compare them with detectors trained on Sentinel‑2.
• Design and implement optical–radar fusion strategies in PyTorch, building on the team’s existing codebase.
• Report and summarise the results

Additional activities:

• Contribute an extension of the BAISen2 dataset with Sentinel‑1 data, to be released openly.
• If the results allow, prepare a scientific paper for submission to an international journal or conference.

Skills

Technical skills and level required:

• Advanced Python programming skills
• Proficiency in deep learning with PyTorch
• Background in machine learning, computer vision or remote sensing
• Experience with object detection is appreciated
• Experience with SAR or satellite data is a plus

Languages:

• French: a plus but not necessary

Relational skills:

• Ability to work both on your own and in a team
• Communication skills, including presenting research results and working in an interdisciplinary team
• Analytical thinking and problem solving
• Curiosity and a continuous-learning mindset

Other valued skills:

• Interest in Earth observation and coastal applications

Benefits package

• Partial reimbursement of public transport costs
• Leave: 7 weeks of annual leave + 10 extra days off due to RTT (statutory reduction in working hours) + possibility of exceptional leave (sick children, moving home, etc.)
• Possibility of teleworking and flexible organization of working hours
• Professional equipment available (videoconferencing, loan of computer equipment, etc.)
• Social, cultural and sports events and activities
• Access to vocational training
• Employer-sponsored health insurance plan

Remuneration

• Theme/Domain :Earth, Environmental and Energy Sciences Scientific computing(BAP E)

Instruction to apply

Defence Security : This position is likely to be situated in a restricted area (ZRR), as defined in Decree No. 2011-1425 relating to the protection of national scientific and technical potential (PPST). Authorisation to enter an area is granted by the director of the unit, following a favourable Ministerial decision, as defined in the decree of 3 July 2012 relating to the PPST. An unfavourable Ministerial decision in respect of a position situated in a ZRR would result in the cancellation of the appointment.

Recruitment Policy : As part of its diversity policy, all Inria positions are accessible to people with disabilities.

We are looking for a curious and rigorous student who enjoys working with real-world satellite data and is motivated by applications with a societal impact, such as beach safety. Solid skills in deep learning with PyTorch are essential. An interest in Earth observation and a willingness to explore a new modality (SAR) are real assets, and you don’t need to be a radar expert.

About Inria

Inria, the French national institute for research in digital science and technology, supports the French government in national research and innovation strategies in the digital field, acting as Digital Programs Agency. Inria leads over 300 research and innovation projects with its 3,500 scientists, engineers, and support staff, in partnership with universities and the digital ecosystem (businesses, entrepreneurs, and public stakeholders). Together, we explore strategic fields such as artificial intelligence, cybersecurity, quantum computing, cloud technologies, digital transformation in healthcare, digital twins, and digital technologies for defence. We develop practical solutions such as software, tech startups, partnerships with national companies, and cutting‑edge training programmes. Our goal is to drive scientific, technological, and industrial excellence to ensure France’s digital sovereignty.