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Panagiotis Agrafiotis

I am a postdoctoral researcher (Researcher B) at the National Technical University of Athens (NTUA), where I also obtained my Engineering Doctorate. I am currently doing research in the areas of 3D computer vision, remote sensing and machine learning. I hold a M. Eng. Diploma in Rural and Surveying Engineering and a M.Sc. in Geoinformatics from the same university. During my studies, I earned various awards and travel grants for conferences and a full PhD Scholarship from NTUA. In December 2020, my team, won the 1st Prize of the integrated Geomatics solution awarded by the European GNSS Agency for our proposal “Bathymetry from UAV Imagery and Machine Learning”. The last 9 years I lived in Greece and Cyprus, working in more than 16 research projects as a researcher at the Photogrammetric Vision Lab. of CUT, the Lab. of Photogrammetry of NTUA and the Institute of Communication and Computer Systems (ICCS) of the School of Electrical and Computer Engineering (ECE) of the NTUA, with the responsibility of applied computer vision algorithms design, overwater and underwater 3D reconstruction, machine learning, laser scanning, cameras calibration and person detection and tracking for survivor localization on optical and thermal imagery. My current research focuses on image-based bathymetry mapping for shallow waters using machine learning, image processing and image analysis. I am author of 34 scientific publications and I have served as a reviewer in 10 journals of high impact factor. I have participated in the organizing committee of 2 international conferences and in the scientific committee of 6 more. I am currently the secretary of the ISPRS WG II/9: Underwater Data Acquisition and Processing.

News:

March 2021: Invited presentation at Politecnico di Torino on "Two media bathymetric mapping for shallow waters" in the context of Heritage Week 2021. [Presentation]

March 2021: Journal article "Needs and Gaps in Optical Underwater Technologies and Methods for the Investigation of Marine Animal Forest 3D-Structural Complexity" [article]

February 2021: Invited lecture at Cyprus Univarsity of Technology on "Bathymetry from active and passive UAV-borne, airborne and satellite-borne remote sensing" in the context of Geoinformatics and Geospatial Technologies Master's Programme.

December 2020: I am serving as a guest editor of the Special Issue "Remote Sensing for Shallow and Deep Waters Mapping and Monitoring.

December 2020: Got awarded with the 1st Prize of the Integrated Geomatics solution by the European GNSS Agency for the proposal “Bathymetry from UAV Imagery and Machine Learning”, during the Geomatics on the Move contest.

October 2020: Feature article on "Bathymetry from UAV Imagery and Machine Learning" in Hydro International and GIM. The article ranked 2nd in the top 10 articles & news atories for 2020 for Hydro International.

October 2020: Shoreline extraction and isoheight/isodetph maps produced after processing UAV imagery for image based bathymetry.

September 2020: Invited presentation at IMS-FORTH on "Photogrammetry and Machine Learning for Cultural Heritage" in the context of STABLE Summer School. [Presentation]

July 2020: Successful defence of my Doctoral Dissertation at the National Technical University of Athens, entitled "Image-based bathymetry mapping for shallow waters".

April 2020: Book chapter "Skarlatos, D. and Agrafiotis, P.: Image-Based Underwater 3D Reconstruction for Cultural Heritage: From Image Collection to 3D. Critical Steps and Considerations" [chapter]

February 2020: Aerial Semantic Segmentation for HD seabed mapping (left) and HD archaeological mapping (right).


January 2020: Journal article "Agrafiotis, P., Karantzalos, K., Georgopoulos, A. and Skarlatos, D.: Correcting Image Refraction: Towards Accurate Aerial Image-Based Bathymetry Mapping in Shallow Waters., Remote Sens. 2020, 12, 322." [webpage] [article] [demo (TBA)]

December 2019: Invited lecture on "3D Computer Vision" at the School of Rural and Surveying Engineering of National Technical University of Athens (NTUA).

September 2019: Journal article "Agrafiotis, P., Skarlatos, D., Georgopoulos, A., and Karantzalos, K.: DepthLearn: Learning to Correct the Refraction on Point Clouds Derived from Aerial Imagery for Accurate Dense Shallow Water Bathymetry Based on SVMs-Fusion with LiDAR Point Clouds., Remote Sens. 2019, 11, 2225." [webpage] [article] [demo (TBA)]

mber 2019: Tutorial about Underwater Photogrammetry for Cultural Heritage helded within the context of 27th International CIPA symposium, held on 1-5 September 2019 in Avila, Spain.

July 2019: Tests on contextual classification of aerial images (RGBN) using CRFs and FCNs (based on SegNet architecture)


May 2019: Paper "Agrafiotis, P., Skarlatos, D., Georgopoulos, A., and Karantzalos, K.: SHALLOW WATER BATHYMETRY MAPPING FROM UAV IMAGERY BASED ON MACHINE LEARNING, Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., XLII-2/W10, 9-16, https://doi.org/10.5194/isprs-archives-XLII-2-W10-9-2019, 2019." [webpage] [paper] [demo (TBA)]

February 2019: Invited lectures on "Photogrammetric Computer Vision" and on "Underwater 3D recording and mapping for Cultural Heritage" at Cyprus University of Technology.

October 2018: Journal article: "Guidelines for Underwater Image Enhancement Based on Benchmarking of Different Methods" [article]

October 2018: Invited lecture on "Underwater 3D recording and mapping for Cultural Heritage" in the context of the "Cultural Heritage Documentation" Course of the School of Rural and Surveying Engineering of National Technical University of Athens (NTUA).

October 2018: Invited lecture on "Photogrammetric Computer Vision" in the context of the "Cultural Heritage Documentation" Course of the School of Rural and Surveying Engineering of National Technical University of Athens (NTUA).

September 2018 Documentary on Euronews about iMARECULTURE project.

September 2018: Journal article: "State of the art and applications in archaeological underwater 3D recording and mapping", in Journal of Cultural Heritage [article]

August 2018: Testing the BlueROV2 of the Photogrammetric Vision Lab after the modification we made at CUT facilities in order to facilitate the coloured photogrammetric data aquisition. During the week more tests will be performed in the open sea and depths reaching the 40m bellow the sea level.


July 2018: Testing the AR technologies we developed in the iMARECULTURE project within the Underwater Archeological Park of Baia. Visit here for more information. Image 1. Image 2.

June 2018: Paper about a caustics detection and removal approach based on Convolutional Neural Networks (CNN) and it's effect on image keypoint and matching processes"

June 2018: Journal article: "A Novel Iterative Water Refraction Correction Algorithm for Use in Structure from Motion Photogrammetric Pipeline, J. Mar. Sci. Eng. 2018, 6, 77."

April 2018: The 3D documentation of the archaeological site of Poliochne in the Greek island of Lemnos is perfromed by the Lab. of Photogrammetry of National Technical University of Athens . It is part of a Partneship Agreement 2014-2020 project coordinated by the Ephorate of Antiquities of Lesbos aiming in restoring, preserving and highlighting the archaeological site.


January 2018: Book chapter in "Latest Developments in Reality-Based 3D Surveying and Modelling" [chapter]


About radial distortion elimination algorithms and software

Contact

Email: pagraf [at] central [dot] ntua [dot] gr

Address:
School of Rural and Surveying Engineering National Technical University of Athens
9 Iroon Polytechneiou Str. - 157 80, Zographou, Athens, Greece