Viktoria Kristollari

Remote Sensing and Machine Learning expert

I have worked as a researcher at the Remote Sensing Lab (RSLab) of National Technical University of Athens (NTUA). I have also been a teaching assistant at the course "Special Topics of Remote Sensing" of the RSLab. The subject of my PhD research was the investigation and development of machine learning methods for multispectral/hyperspectral Remote Sensing applications.

I have been involved in a broad spectrum of Remote Sensing/Image processing applications including medical, thermal and SAR image processing, unmixing methodologies and 3D modelling. I have also reviewed papers submitted to Remote Sensing journals and I have participated in proposal writing for European and Greek research calls.

email: Email linkedin: Linkedin github: Github researchgate: Researchgate academia.edu: Academia orcid: Orcid google scholar: Google


Experience

Researcher at RSLab NTUA

REACT project React
June 2020 - June 2022

Crowdsourcing, Copernicus and Hyperspectral Satellite Data for Marine Plastic Litter Detection, Quantification and Tracking (funded by ESA).
Responsible for:
- the implementation of deep learning approaches for the pansharpening of PRISMA data and the fusion of Sentinel-2 and Worldview images.
- the development of marine plastic litter indexes.

HYPERION project Hyperion
February 2020 - December 2021

Development of a Decision Support System for Improved Resilience & Sustainable Reconstruction of historic areas to cope with Climate Change & Extreme Events based on Novel Sensors and Modelling Tools (Horizon 2020).
Responsible for developing land cover change maps through deep learning approaches.
Project website: https://www.hyperion-project.eu/

ASTARTE project Astarte
March 2020 - June 2020

Analysis of SAR and thermal satellite data time-series for understanding the long-term impact of land surface temperature changes on forests.
Participation in the cloud masking process.
Project website: http://astarte.cut.ac.cy/project/

SEO-DWARF project Seodwarf
January 2018 - January 2019

Semantic EO Data Web Alert and Retrieval. A Marie Skłodowska-Curie Research And Innovation Staff Exchange (MSCA-RISE) action (Horizon 2020).
Seconded researcher at CloudSigma (Sofia, Bulgaria), Planetek Italia (Bari, Italy), TWT (Stuttgart, Germany), i-Sea (Bordeaux, France). Responsible for the creation of cloud masks through deep learning approaches. The secondments in each company lasted for 3 months.
Project website: https://seo-dwarf.eu/

MARERIAL project
March 2017 - February 2018

Investigation of the spectral properties of urban materials for the creation of product for Calcon GmbH (Munich) (Working remotely)
Collection of urban spectral signatures in Athens and Munich with hyperspectral VNIR and SWIR sensors.
Spectral data annotation and analysis.

2017 - 2023

Teaching assistant at RSLab NTUA

Course: "Special Topics of Remote Sensing".

2019 - 2020

Full-body hyperspectral scanning

Scanning of psoriatic patients in a Greek dermatology clinic as part of the data collection of my diploma thesis.

October 2015 - May 2016

Geometric Documentation of the Temple of Haephestus

Semester Course (Monument Recording).
Creation of 3d model of the monument by photogrammetric methods and by use of laser point cloud.
Production of architectural drawings.

October 2014 - February 2015

Surveying Summer Internship

Topographic and cadastral survey of Sikinos island, Greece.
Use of a wide range of field surveying equipment.

July 2013

Topographic Survey in the Zografou campus of NTUA

Surveying Summer Course.

June 2012 - July 2012

Education

National Technical University of Athens

Doctor of Engineering

Subject title: Artificial Neural Networks for multispectral/hyperspectral earth observation data applications.

2017 - 2023

National Technical University of Athens

Integrated Master of Science
Rural, Surveying and Geoinformatics Engineering (ranked 2nd, Grade: 8.58/10)

Diploma Thesis title: "Automatic Hyperspectral Method for the Detection, Recognition and Scoring of Erythema in Psoriasis"
61 courses are required for the completion of studies. The following courses were among the courses that were completed:
- Photo-interpretation and Remote Sensing
- Digital Image Analysis for Remote Sensing
- Special Topics of Remote Sensing
- Radiometry and Microwave Remote Sensing
- Photogrammetry I (Introduction to Photogrammetry)
- Photogrammetry II (Analytical Photogrammetry)
- Photogrammetry III (Digital Photogrammetry)
- Photographic Data Acquisition
- Geographical Information Systems
- Geodesy V (Satellite Geodesy)
- Cadastre and Land Information Systems
- Cartography I (General Cartography)
- Cartography II (Analytical Cartography)
- Database Systems
- Digital Mapping

2010 - 2016

16th HIGH SCHOOL OF ATHENS

High School Diploma

Grade:19.6/20

2007 - 2010

Skills

Tools
ESA SNAP: Snap Exelis ENVI: ENVI Erdas Ermapper: ERmapper Erdas Imagine: Imagine Opticks: Opticks Ecognition: Ecognition ENVI Sarscape: SarScape

ESRI Arcgis: Arcgis Qgis:Qgis Autocad Civil 3D: Autocad Agisoft Photoscan: Photoscan Photomod: Photomod Photoshop: Photoshop


Programming languages
  • Python (very good knowledge)
  • Matlab (very good knowledge)
  • C++ (fair knowledge)
  • IDL (fair knowledge)

Deep learning frameworks
  • Keras/Tensorflow
  • Pytorch

Languages
  • English(level C2)
  • French (level B2)
  • German (level B1)
  • Greek (native)

Publications

-Karathanassi V., Karamvasis K., Kristollari V., Skamantzari M., and Georgopoulos A. "Remote sensing techniques for monitoring cultural heritage sites." In EGU General Assembly 2024, April 2024.
[abstract]

-Aiello A., Barbone E., Karathanassi V., Kolokoussis P., Kremezi M., Kristollari V., and Taggio N. "Unlocking the Potential of Spectral Signature Unmixing and Machine Learning for Detecting Plastic Marine Litter: Insights from the REACT Project." In ESA Remote Sensing of Marine Litter Workshop, October 2023.
[abstract]

-Kremezi M., Kristollari V., Karathanassi V., and Kolokoussis P. "Enhancing PRISMA and Sentinel 2 Capabilities for Marine Plastic Litter Detection Using Image Fusion Techniques, Spectral Signature Unmixing and Spectral Indexes." In 41st EARSeL Symposium, September 2022.
[researchgate access: RG ] [presentation] [abstract]

-Kremezi M., Kristollari V., Karathanassi V., Topouzelis K., Kolokoussis P., Taggio N., Aiello A., Ceriola G., Barbone E., and Corradi P. "Increasing the Sentinel-2 potential for marine plastic litter monitoring through image fusion techniques." Marine Pollution Bulletin 182 (2022): 113974.
[publisher access: IEEE] [preprint] [related code: Github ]

-Taggio N., Aiello A., Ceriola G., Kremezi M, Kristollari V., Kolokoussis P., Karathanassi V., and Barbone E. " A Combination of Machine Learning Algorithms for Marine Plastic Litter Detection Exploiting Hyperspectral PRISMA Data "Remote Sensing 14, no. 15 (2022): 3606.
[publisher access: MDPI] [researchgate access: RG ]

-Kristollari V., and Karathanassi V. "Change Detection in VHR Imagery With Severe Co-Registration Errors Using Deep Learning: A Comparative Study." IEEE Access 10 (2022): 33723-33741.
[publisher access: IEEE] [researchgate access: RG ] [related code: Github ]

-Kremezi M., Kristollari V., Karathanassi V., Topouzelis K., Kolokoussis P., Taggio N., Aiello A., Ceriola G., Barbone B., and Corradi P. "Pansharpening PRISMA Data for Marine Plastic Litter Detection Using Plastic Indexes." IEEE Access 9 (2021): 61955-61971.
[publisher access: IEEE] [researchgate access: RG ] [related code: Github ]

-Kristollari V., and Karathanassi V. "Convolutional neural networks for detecting challenging cases in cloud masking using Sentinel-2 imagery." In Eighth International Conference on Remote Sensing and Geoinformation of the Environment (RSCy2020), vol. 11524, p. 115240K. International Society for Optics and Photonics, 2020.
[publisher access: Spie] [researchgate access: RG ] [related code: Github ]

-Kristollari V., and Karathanassi V. "Fine-Tuning Self-Organizing Maps for Sentinel-2 Imagery: Separating Clouds from Bright Surfaces." Remote Sensing 12, no. 12 (2020): 1923.
[publisher access: MDPI] [researchgate access: RG ] [related code: Github ]

-Kristollari V., and Karathanassi V. "Artificial neural networks for cloud masking of Sentinel-2 ocean images with noise and sunglint." International Journal of Remote Sensing 41, no. 11 (2020): 4102-4135.
[publisher access: Taylor] [related code: Github ] [related dataset: Figshare ] [preprint]

-Kristollari V., "Automatic hyperspectral method for the detection, recognition and scoring of erythema in psoriasis" NTUA, thesis (2016).
[NTUA access: NTUA]

-Kremezi M. and Kristollari V., "Accuracy assessment of the Agisoft Photoscan software" NTUA, technical report (2014).
[researchgate access: researchgate] [academia.edu access: academia] [presentation]


Honors & Awards

  • 3 year scholarship awarded by the NTUA Special Account for Research Funds as a financial support for my PhD research (2017).
  • Limmat Stiftung Excellence Award (1 st prize, 2016)
  • Teenage member of the Greek Parliament (2009-2010)