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Kerekes, Gabriel

Gabriel Kerekes

Dr.-Ing.

Head of Section 3D Data Acquisition and Monitoring
Institute of Engineering Geodesy Stuttgart
Faculty 6: Aerospace Engineering and Geodesy

Contact

+49 711 685 84051
Email

Geschwister-Scholl-Str. 24D
70174 Stuttgart
Germany

Subject

Terrestrial Laser Scanning
Surveying Engineering
3D Data Acquisition and Monitoring

Publications

Kerekes, G., & Schwieger, V. (2025). Correlations in TLS point clouds: Should we care about them? Proceedings of 6th Joint International Symposium on Deformation Monitoring (JISDM), Karlsruhe, Germany, 7-9 April, 2025. https://jisdm2025.gik.kit.edu/downloads/JISDM2025_Kerekes_and_Schwieger.pdf
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@inproceedings{kerekes2025correlations, author = {Kerekes, Gabriel and Schwieger, Volker}, booktitle = {Proceedings of 6th Joint International Symposium on Deformation Monitoring (JISDM), Karlsruhe, Germany, 7-9 April, 2025}, title = {Correlations in TLS point clouds: Should we care about them?}, url = {https://jisdm2025.gik.kit.edu/downloads/JISDM2025_Kerekes_and_Schwieger.pdf}, year = 2025 }
Link
https://jisdm2025.gik.kit.edu/downloads/JISDM2025_Kerekes_and_Schwieger.pdf
Spyridonos, E., Costalonga, V., Petrš, J., Kerekes, G., Schwieger, V., & Dahy, H. (2025). Enhancing construction accuracy with biocomposites through 3D scanning methodology: Case studies applying Pultrusion, 3D Printing, and Tailored Fibre Placement. Case Studies in Construction Materials, 22, e04499. https://doi.org/10.1016/j.cscm.2025.e04499
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@article{spyridonos2025enhancing, abstract = {The building industry is increasingly adopting bio-based materials to meet the growing demand for environmentally friendly alternatives. Composites, known for their diverse properties and adaptable geometries, are gaining popularity as a versatile choice for customising materials for specific applications. This paper presents a 3D scanning methodology to enhance construction accuracy with sustainable building materials. It introduces three fabrication technologies for fibre-reinforced biocomposites and the resulting building components and structures at different scales achieved with each method. Pultrusion is employed to produce natural fibre biocomposite profiles used in an active-bending structural system. 3D Printing (3DP) is utilised to create a modular column using natural fibre-reinforced bioplastic, while Tailored Fibre Placement (TFP) is applied to fabricate biocomposite facade panels with varying geometries. The three case studies demonstrate the use of scanning technology to improve fabrication and assembly processes, with geometric accuracy evaluated through Terrestrial Laser Scanning (TLS) during construction, allowing for a detailed comparison of the built structures with the digital models. Scanning revealed that pultrusion produced accurate components but exhibited up to 160 mm deviations in large-scale freeform assemblies. 3DP can achieve high component manufacturing accuracy with deviations below 5 mm, though modular assembly introduced accumulated errors reaching 40 mm. TFP deviations varied between −48 and 60 mm, with different shaping approaches helping to reduce errors. A comparative analysis of the three methods provides recommendations for improving fabrication and assembly processes while establishing a framework for the future integration of biocomposites as structural components in architectural systems.}, author = {Spyridonos, Evgenia and Costalonga, Vanessa and Petrš, Jan and Kerekes, Gabriel and Schwieger, Volker and Dahy, Hanaa}, doi = {https://doi.org/10.1016/j.cscm.2025.e04499}, issn = {2214-5095}, journal = {Case Studies in Construction Materials}, pages = {e04499}, title = {Enhancing construction accuracy with biocomposites through 3D scanning methodology: Case studies applying Pultrusion, 3D Printing, and Tailored Fibre Placement}, url = {https://www.sciencedirect.com/science/article/pii/S2214509525002979}, volume = 22, year = 2025 }
Link
https://www.sciencedirect.com/science/article/pii/S2214509525002979
Kerekes, G., & Schwieger, V. (2024). An approach for considering the object surface properties in a TLS stochastic model. Journal of Applied Geodesy, 18, 115–131. https://doi.org/doi:10.1515/jag-2022-0032
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@article{KerekesSchwieger+2024+115+131, author = {Kerekes, Gabriel and Schwieger, Volker}, doi = {doi:10.1515/jag-2022-0032}, journal = {Journal of Applied Geodesy}, lastchecked = {2024-01-29}, pages = {115--131}, title = {An approach for considering the object surface properties in a TLS stochastic model}, url = {https://doi.org/10.1515/jag-2022-0032}, volume = 18, year = 2024 }
Link
https://doi.org/10.1515/jag-2022-0032
Kerekes, G., & Schwieger, V. (2024). Possibilities and Limitations in the extrinsic Synchronization of Observations from Networks of Robotic Total Stations. FIG Working Week Accra 2024.
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@article{kerekes2024possibilities, author = {Kerekes, Gabriel and Schwieger, Volker}, journal = {FIG Working Week Accra 2024}, title = {Possibilities and Limitations in the extrinsic Synchronization of Observations from Networks of Robotic Total Stations}, year = 2024 }
Kerekes, G. (2023). An elementary error model for terrestrial laser scanning [Dissertation, Universität Stuttgart]. In Deutsche Geodätische Kommission: Reihe C, Heft Nr. 900, Verlag der Bayerischen Akademie der Wissenschaften. https://dgk.badw.de/fileadmin/user_upload/Files/DGK/docs/c-900.pdf
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@phdthesis{kerekes2023elementary, author = {Kerekes, Gabriel}, booktitle = {Deutsche Geodätische Kommission: Reihe C, Heft Nr. 900, Verlag der Bayerischen Akademie der Wissenschaften}, doi = {https://dgk.badw.de/fileadmin/user_upload/Files/DGK/docs/c-900.pdf}, language = {eng}, school = {Universität Stuttgart}, title = {An elementary error model for terrestrial laser scanning}, type = {Dissertation}, url = {http://dx.doi.org/10.18419/opus-12955}, year = 2023 }
Link
http://dx.doi.org/10.18419/opus-12955
Hassan, A., Zhang, L., Kerekes, G., & Schwieger, V. (2022). Geodetic Data Fusion for Rock Cliff Monitoring: a Case Study of the Lianzi Cliff in Three Gorges National Geological Park in China. XXVII FIG Congress 2022, Warsaw, Poland. https://fig.net/resources/proceedings/fig_proceedings/fig2022/papers/ts04d/TS04D_hassan_zhang_et_al_11340.pdf
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@inproceedings{hassan2022fusion, author = {Hassan, Aiham and Zhang, Li and Kerekes, Gabriel and Schwieger, Volker}, booktitle = {XXVII FIG Congress 2022, Warsaw, Poland.}, title = {Geodetic Data Fusion for Rock Cliff Monitoring: a Case Study of the Lianzi Cliff in Three Gorges National Geological Park in China}, url = {https://fig.net/resources/proceedings/fig_proceedings/fig2022/papers/ts04d/TS04D_hassan_zhang_et_al_11340.pdf}, year = 2022 }
Link
https://fig.net/resources/proceedings/fig_proceedings/fig2022/papers/ts04d/TS04D_hassan_zhang_et_al_11340.pdf
Kerekes, G., Petrš, J., Schwieger, V., & Dahy, H. (2022). Geometric quality control for bio-based building elements: Study case segmented experimental shell. Journal of Applied Geodesy. https://doi.org/doi:10.1515/jag-2020-0035
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@article{KerekesPetršSchwiegerDahy+2022, author = {Kerekes, Gabriel and Petrš, Jan and Schwieger, Volker and Dahy, Hanaa}, doi = {doi:10.1515/jag-2020-0035}, journal = {Journal of Applied Geodesy}, title = {Geometric quality control for bio-based building elements: Study case segmented experimental shell}, url = {https://doi.org/10.1515/jag-2020-0035}, year = 2022 }
Link
https://doi.org/10.1515/jag-2020-0035
Kerekes, G., Jakob, R., Harmening, C., Neuner, H., & Schwieger, V. (2022). Two-epoch TLS deformation analysis of a double curved wooden structure using approximating B-spline surfaces and fully-populated synthetic covariance matrices. 5th Joint International Symposium on Deformation Monitoring (JISDM), 20-22 April 2022, Valencia, Spain. http://ocs.editorial.upv.es/index.php/JISDM/JISDM2022/paper/viewFile/13816/7605
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@inproceedings{kerekes2022twoepoch, author = {Kerekes, Gabriel and Jakob, Raschhofer; and Harmening, Corinna and Neuner, Hans and Schwieger, Volker}, booktitle = {5th Joint International Symposium on Deformation Monitoring (JISDM), 20-22 April 2022, Valencia, Spain. }, title = {Two-epoch TLS deformation analysis of a double curved wooden structure using approximating B-spline surfaces and fully-populated synthetic covariance matrices}, url = {http://ocs.editorial.upv.es/index.php/JISDM/JISDM2022/paper/viewFile/13816/7605}, year = 2022 }
Link
http://ocs.editorial.upv.es/index.php/JISDM/JISDM2022/paper/viewFile/13816/7605
Kerekes, G., & Schwieger, V. (2021). Towards Perceived Space Representation using Brain Activity, Eye-Tracking and Terrestrial Laser Scanning. In A. Basiri, G. Gartner, & H. Huang (Eds.), Contributions to International Conferences on Engineering Surveying (pp. 57–68). https://doi.org/doi.org/10.34726/1788
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@inproceedings{kerekes2021towards, author = {Kerekes, Gabriel and Schwieger, Volker}, booktitle = {Contributions to International Conferences on Engineering Surveying}, doi = {doi.org/10.34726/1788}, editor = {Basiri, A. and Gartner, G. and Huang, H.}, isbn = {978-3-030-51953-7}, pages = {57-68}, title = {Towards Perceived Space Representation using Brain Activity, Eye-Tracking and Terrestrial Laser Scanning}, year = 2021 }
Kerekes, G., & Schwieger, V. (2021). Determining Variance-Covariance Matrices for Terrestrial Laser Scans: A Case Study of the Arch Dam Kops. In A. Kopácik, P. Kyrinovic, J. Erdélyi, R. Paar, & A. Marendić (Eds.), Contributions to International Conferences on Engineering Surveying (pp. 57–68). Springer, Cham. https://doi.org/10.1007/978-3-030-51953-7_5
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@inproceedings{kerekes2021determining, abstract = {Deformation and displacement monitoring of arch dams is usually conducted by measurement methods that gained widespread acceptance. Mostly pointwise measurements acquired within different epochs serve as the basis for deformation analysis. The uncertainty information of these observations is generally established. When referring to surface-based deformation monitoring, terrestrial laser scanning (TLS) is intensively hyped up. Nevertheless, current knowledge about stochastic modelling of TLS observations is scarce and very often reduced to a diagonal variance-covariance matrix (VCM). This neglects the exiting correlations within the point clouds. Aiming to fill the gap, this paper shows one possibility of obtaining a fully populated variance-covariance matrix using the elementary error model (EEM). Previous publications on this topic described the application of EEM for the Leica HDS 7000 laser scanner and showed results on simulated data for laboratory objects. Within this paper instrumental errors of the same scanner are modeled differently, according to recent work. A real scan of the arch dam Kops in Austria highlights influences on the variances, covariances and correlations of points within the point cloud for two instrument error models. Findings show that the model choice does not bring a notable change in the error of positions, but influences the correlation coefficients up to a level of $\Delta$$\rho${\thinspace}={\thinspace}0.2.}, author = {Kerekes, Gabriel and Schwieger, Volker}, booktitle = {Contributions to International Conferences on Engineering Surveying}, doi = {https://doi.org/10.1007/978-3-030-51953-7_5}, editor = {Kop{\'a}{\v{c}}ik, Alojz and Kyrinovi{\v{c}}, Peter and Erd{\'e}lyi, J{\'a}n and Paar, Rinaldo and Marendi{\'{c}}, Ante}, isbn = {978-3-030-51953-7}, pages = {57--68}, publisher = {Springer, Cham}, title = {Determining Variance-Covariance Matrices for Terrestrial Laser Scans: A Case Study of the Arch Dam Kops}, year = 2021 }
Raschhofer, J., Kerekes, G., Harmening, C., Neuner, H., & Schwieger, V. (2021). Estimating Control Points for B-Spline Surfaces Using Fully Populated Synthetic Variance–Covariance Matrices for TLS Point Clouds. Remote Sensing, 13, Article 16. https://doi.org/10.3390/rs13163124
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@article{raschhofer2021estimating, author = {Raschhofer, Jakob and Kerekes, Gabriel and Harmening, Corinna and Neuner, Hans and Schwieger, Volker}, doi = {10.3390/rs13163124}, issn = {2072-4292}, journal = {Remote Sensing}, language = {eng}, number = 16, pages = 3124, publisher = {MDPI}, title = {Estimating Control Points for B-Spline Surfaces Using Fully Populated Synthetic Variance–Covariance Matrices for TLS Point Clouds}, volume = 13, year = 2021 }
Kerekes, G., & Schwieger, V. (2020). Elementary Error Model Applied to Terrestrial Laser Scanning Measurements: Study Case Arch Dam Kops. Mathematics 2020, Vol. 8(4) 593. https://doi.org/10.3390/math8040593
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@article{kerekes2020elementary, abstract = {All measurements are affected by systematic and random deviations. A huge challenge is to correctly consider these effects on the results. Terrestrial laser scanners deliver point clouds that usually precede surface modeling. Therefore, stochastic information of the measured points directly influences the modeled surface quality. The elementary error model (EEM) is one method used to determine error sources impact on variances-covariance matrices (VCM). This approach assumes linear models and normal distributed deviations, despite the non-linear nature of the observations. It has been proven that in 90% of the cases, linearity can be assumed. In previous publications on the topic, EEM results were shown on simulated data sets while focusing on panorama laser scanners. Within this paper an application of the EEM is presented on a real object and a functional model is introduced for hybrid laser scanners. The focus is set on instrumental and atmospheric error sources. A different approach is used to classify the atmospheric parameters as stochastic correlating elementary errors, thus expanding the currently available EEM. Former approaches considered atmospheric parameters functional correlating elementary errors. Results highlight existing spatial correlations for varying scanner positions and different atmospheric conditions at the arch dam Kops in Austria.}, article-number = {593}, author = {Kerekes, Gabriel and Schwieger, Volker}, doi = {10.3390/math8040593}, issn = {2227-7390}, journal = {Mathematics 2020}, note = {peer-review}, title = {Elementary Error Model Applied to Terrestrial Laser Scanning Measurements: Study Case Arch Dam Kops}, volume = {Vol. 8(4) 593}, year = 2020 }
Schwieger, V., Kerekes, G., & Lerke, O. (2020). Image-Based Target Detection and Tracking Using Image-Assisted Robotic Total Stations. In O. Sergiyenko, W. Flores-Fuentes, & P. Mercorelli (Eds.), Machine Vision and Navigation. Springer, Cham. https://link.springer.com/chapter/10.1007%2F978-3-030-22587-2_5
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@inbook{schwieger2020imagebased, author = {Schwieger, Volker and Kerekes, Gabriel and Lerke, Otto}, booktitle = {Machine Vision and Navigation}, doi = {https://link.springer.com/chapter/10.1007%2F978-3-030-22587-2_5}, editor = {Sergiyenko, O. and Flores-Fuentes, W. and Mercorelli, P.}, publisher = {Springer, Cham }, title = {Image-Based Target Detection and Tracking Using Image-Assisted Robotic Total Stations}, url = {https://doi.org/10.1007/978-3-030-22587-2_5}, year = 2020 }
Link
https://doi.org/10.1007/978-3-030-22587-2_5
Schwieger, V., Lerke, O., & Kerekes, G. (2019). Image-Based Target Detection and Tracking Using Image-Assisted Robotic Total Stations. FIG Working Week 2019, Hanoi, Vietnam, 22.-26.04.
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@inproceedings{schwieger2019imagebased, author = {Schwieger, Volker and Lerke, Otto and Kerekes, Gabriel}, booktitle = {FIG Working Week 2019, Hanoi, Vietnam, 22.-26.04.}, title = {Image-Based Target Detection and Tracking Using Image-Assisted Robotic Total Stations}, year = 2019 }
Kerekes, G., & Schwieger, V. (2018). Position Determination of a Moving Reflector in Real Time by Robotic Total Station Angle Measurements. RevCAD Journal of Geodesy and Cadastre, No 9 / 2018. https://jgcc.geoprevi.ro/docs/2018/9/jgcc_2018_no9_2.pdf
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@inproceedings{kerekes2018position, author = {Kerekes, Gabriel and Schwieger, Volker}, booktitle = {International Symposium GeoPreVi 2018, Bucharest, Romania}, issn = {1454-1408}, journal = {RevCAD Journal of Geodesy and Cadastre}, title = {Position Determination of a Moving Reflector in Real Time by Robotic Total Station Angle Measurements}, url = {https://jgcc.geoprevi.ro/docs/2018/9/jgcc_2018_no9_2.pdf}, volume = {No 9 / 2018}, year = 2018 }
Link
https://jgcc.geoprevi.ro/docs/2018/9/jgcc_2018_no9_2.pdf
Kerekes, G., & Schwieger, V. (2018). Kinematic Positioning in a Real Time Robotic Total Station Network System. 6th International Conference on Machine Control and Guidance. Berlin, Germany, Bornimer Agrartechnische Berichte Heft 101, 35–43.
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@inproceedings{kerekes2018kinematic, author = {Kerekes, Gabriel and Schwieger, Volker}, booktitle = {6th International Conference on Machine Control and Guidance. Berlin, Germany}, issn = {ISSN 0947-7314}, pages = {35-43}, title = {Kinematic Positioning in a Real Time Robotic Total Station Network System}, volume = {Bornimer Agrartechnische Berichte Heft 101}, year = 2018 }
Kerekes, G. (2013). Open Source 3D Modeling from Raster Images. Young Researchers Conference at the Technical University of Civil Engineering, Bucharest, Romania, In: Mathematical Modelling in Civil Engineering, Special Issue, 84–89. https://mcee.utcb.ro/images/doc/2013/Scientific_Journal_-_Special_issue_-_november_2013.pdf
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@inproceedings{kerekes2013source, author = {Kerekes, Gabriel}, booktitle = {Young Researchers Conference at the Technical University of Civil Engineering, Bucharest, Romania}, pages = {84-89}, title = {Open Source 3D Modeling from Raster Images}, url = {https://mcee.utcb.ro/images/doc/2013/Scientific_Journal_-_Special_issue_-_november_2013.pdf}, volume = {In: Mathematical Modelling in Civil Engineering, Special Issue}, year = 2013 }
Link
https://mcee.utcb.ro/images/doc/2013/Scientific_Journal_-_Special_issue_-_november_2013.pdf
Kerekes, G. (2013). Open Source GIS Cartography for Small Scale Maps. - 8th National Student Symposium ‘’IF-IM-CAD’’. Journal of Young Scientist, Vol.I, Bucharest, Romania, 221–226. http://journalofyoungscientist.usamv.ro/index.php/scientific-papers/past-issues?id=370
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@inproceedings{kerekes2013source, author = {Kerekes, Gabriel}, booktitle = {8th National Student Symposium ‘’IF-IM-CAD’’ }, issn = {2344 - 1283}, journal = {Journal of Young Scientist, Vol.I, Bucharest, Romania}, pages = {221-226}, title = {Open Source GIS Cartography for Small Scale Maps. - 8th National Student Symposium ‘’IF-IM-CAD’’ }, url = {http://journalofyoungscientist.usamv.ro/index.php/scientific-papers/past-issues?id=370}, year = 2013 }
Link
http://journalofyoungscientist.usamv.ro/index.php/scientific-papers/past-issues?id=370
Kerekes, G. (2012). Geospatial analysis of a database for the first order geodetic network of Romania. Proceedings of “In Extenso” Scientific Student’s Communication Session, Alba Iulia, Romania.
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@inproceedings{kerekes2012geospatial, author = {Kerekes, Gabriel}, booktitle = {Proceedings of “In Extenso” Scientific Student’s Communication Session, Alba Iulia, Romania}, title = {Geospatial analysis of a database for the first order geodetic network of Romania}, year = 2012 }

Teaching

Labs	Engineering Geodesy II (Geodesy and Geomatics, Bachelor 6th Semester)
	Integrated Fieldwork (Geodesy and Geomatics, 6th Semester; GEOENGINE, 2nd Semester)

Research Projects

RP 16-2 – Cyber-Physical On-Site Construction Processes using a Spider Crane Robotic Platform

AP 7 – Integrated Space-Time Point Cloud Modelling - IMKAD II

Supervised scientific works

2024 - BA
Großkopf, Julia
Qualitätsbeurteilung der thermographischen Informationen von Punktwolken des Leica BLK360 Laserscanners. (Kerekes/Schwieger)

2024 - BA
Pappas, Stylianos
Untersuchung der Intensitätswerte von TLS-Punktwolken mittels diffus reflektierender Oberflächen. (Kerekes/Schwieger)

2022 - MA
Dalloul, Ahmed
3D model generation through autonomous scanning for infrastructure facilities. (Kerekes/Schwieger)

2021 - BA
Wilczynski, Martin Jan
Verwendbarkeit von mobilen Eye-Tracking Systemen in der geodätischen Messtechnik. (Kerekes/Schwieger)

2020 - MA
Sabzali, Mansoor
Improving the modelling of atmospheric effects on long-range TLS measurements. (Kerekes/Schwieger)

2019 - BA
Hausmann, Nadine
Untersuchung eines TLS auf Nahbereichskorrektur sowie Einsatzmöglichkeiten bei unterschiedlichen Wetterbedingungen. (Kerekes/Metzner)

2019 - BA
Pfitzenmaier, Tobias
Strahldivergenz und Footprint Untersuchung von puls-basierte Laserscannerstrahlen mittels experimentellen Messungen unter Labor- und Feldbedingungen. (Kerekes/Schwieger)

2018 - MA
Dominguez Moran, Luis Eduardo
Reliability and accuracy evaluation of the Direct Reflex Plus – non-reflector measurement mode of the imaging/scanning Total Station Trimble S7 through scenario tests. (Kerekes/Metzner)

2018 - MA
Parra Mendoza, Kevin Eduardo
Displacement and deformation detection of a model structure simulated by a mechanical actuator using the Leica HDS7000 laser scanner. (Kerekes/Schwieger)

2018 - MA
Basalla, Urs
Zielverfolgung mittels von Leica TS16 erfassten Objektbildern. (Kerekes/Schwieger)

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