@inproceedings{KediliogluNovaLandesbergeretal.2025, author = {Kedilioglu, Oguz and Nova, Tasnim Tabassum and Landesberger, Martin and Wang, Lijiu and Hofmann, Michael and Franke, J{\"o}rg and Reitelsh{\"o}fer, Sebastian}, title = {PrIcosa: High-Precision 3D Camera Calibration with Non-Overlapping Field of Views}, booktitle = {Proceedings of the 20th International Joint Conference on Computer Vision, Imaging and Computer Graphics Theory and Applications - (Volume 2)}, editor = {Bashford-Rogers, Thomas and Meneveaux, Daniel and Ammi, Mehdi and Ziat, Mounia and J{\"a}nicke, Stefan and Purchase, Helen and Radeva, Petia and Furnari, Antonino and Bouatouch, Kadi and Sousa, A. Augusto}, publisher = {SciTePress}, address = {Set{\´u}bal}, isbn = {978-989-758-728-3}, doi = {https://doi.org/10.5220/0013088700003912}, pages = {801 -- 809}, year = {2025}, abstract = {Multi-camera systems are being used more and more frequently, from autonomous mobile robots to intelligent visual servoing cells. Determining the pose of the cameras to each other very accurately is essential for many applications. However, choosing the most suitable calibration object geometry and utilizing it as effectively as possible still remains challenging. Disadvantageous geometries provide only subpar datasets, increasing the need for a larger dataset and decreasing the accuracy of the calibration results. Moreover, an unrefined calibration method can lead to worse accuracies even with a good dataset. Here, we introduce a probabilistic method to increase the accuracy of 3D camera calibration. Furthermore, we analyze the effects of the calibration object geometry on the data properties and the resulting calibration accuracy for the geometries cube and icosahedron. The source code for this project is available at GitHub (Nova, 2024).}, language = {en} } @article{LiHofmannLandesbergeretal.2021, author = {Li, Xiaohu and Hofmann, Michael and Landesberger, Martin and Reiberg, Marius and Zhang, Xiao and Huang, Yuanding and Wang, Lijiu and Werner, Ewald and Gan, Weimin}, title = {A Unique Quenching and Deformation Dilatometer for Combined In Situ Neutron Diffraction Analysis of Engineering Materials}, volume = {23}, pages = {2100163}, journal = {Advanced Engineering Materials}, number = {11}, publisher = {Wiley}, address = {Weinheim}, issn = {1527-2648}, doi = {https://doi.org/10.1002/adem.202100163}, year = {2021}, abstract = {A modified quenching and deformation dilatometer (TA instruments DIL 805A/D/T) is now in operation at the Heinz Maier-Leibnitz Zentrum (MLZ, Germany) neutron center. It is customized for running neutron scattering measurements during the temperature/deformation treatment of the sample, in particular neutron diffraction (phase, texture, and lattice strain) and neutron small angle scattering. The bulk length change of dilatometer specimens is successfully combined with in situ neutron diffraction patterns for analyzing dynamic processes in metallic materials. A detailed introduction to the unique dilatometer is given and examples of recent experiments highlight the use of the added insight provided by combining diffraction and dilatometry.}, language = {en} } @article{LandesbergerKediliogluWangetal.2024, author = {Landesberger, Martin and Kedilioglu, Oguz and Wang, Lijiu and Gan, Weimin and Kornmeier, Joana Rebelo and Reitelsh{\"o}fer, Sebastian and Franke, J{\"o}rg and Hofmann, Michael}, title = {High-Precision Visual Servoing for the Neutron Diffractometer STRESS-SPEC at MLZ}, volume = {24}, pages = {2703}, journal = {Sensors}, number = {9}, publisher = {MDPI}, address = {Basel}, issn = {1424-8220}, doi = {https://doi.org/10.3390/s24092703}, year = {2024}, abstract = {With neutron diffraction, the local stress and texture of metallic components can be analyzed non-destructively. For both, highly accurate positioning of the sample is essential, requiring the measurement at the same sample location from different directions. Current sample-positioning systems in neutron diffraction instruments combine XYZ tables and Eulerian cradles to enable the accurate six-degree-of-freedom (6DoF) handling of samples. However, these systems are not flexible enough. The choice of the rotation center and their range of motion are limited. Industrial six-axis robots have the necessary flexibility, but they lack the required absolute accuracy. This paper proposes a visual servoing system consisting of an industrial six-axis robot enhanced with a high-precision multi-camera tracking system. Its goal is to achieve an absolute positioning accuracy of better than 50μm. A digital twin integrates various data sources from the instrument and the sample in order to enable a fully automatic measurement procedure. This system is also highly relevant for other kinds of processes that require the accurate and flexible handling of objects and tools, e.g., robotic surgery or industrial printing on 3D surfaces.}, language = {en} } @inproceedings{KediliogluBoccoLandesbergeretal.2021, author = {Kedilioglu, Oguz and Bocco, Tomas Marcelo and Landesberger, Martin and Rizzo, Alessandro and Franke, J{\"o}rg}, title = {ArUcoE: Enhanced ArUco Marker}, booktitle = {2021 21st International Conference on Control, Automation and Systems (ICCAS)}, publisher = {IEEE}, address = {Piscataway}, isbn = {978-89-93215-21-2}, doi = {https://doi.org/10.23919/ICCAS52745.2021.9650050}, pages = {878 -- 881}, year = {2021}, language = {en} } @article{LiWagnerStarketal.2019, author = {Li, Xiaohu and Wagner, Julia N. and Stark, Andreas and Koos, Robert and Landesberger, Martin and Hofmann, Michael and Fan, Guohua and Gan, Weimin and Petry, Winfried}, title = {Carbon Redistribution Process in Austempered Ductile Iron (ADI) During Heat Treatment—APT and Synchrotron Diffraction Study}, volume = {9}, pages = {789}, journal = {Metals}, number = {7}, publisher = {MDPI}, address = {Basel}, issn = {2075-4701}, doi = {https://doi.org/10.3390/met9070789}, year = {2019}, abstract = {In-situ synchrotron diffraction and atom probe tomography (APT) have been used to study the carbon diffusion and redistribution process in austempered ductile iron (ADI) during austempering. The process of carbon content change in bainitic ferrite during different austempering temperatures has been determined quantitatively. The transformation in ADI is controlled by decarburization of supersaturated ferrite and carbide precipitation and has been found to be divided into three stages based on a model developed for bainitic steels by Takahashi and Bhadeshia. The formation, morphology and composition of carbides and carbon clusters in ferrite after austempering have been identified unequivocally by APT. Finally, the relationships of carbon content in ferrite, carbon gap values, and austempering temperatures in the ADI alloy were expressed using empirical equations.}, language = {en} } @article{LiSaalGanetal.2016, author = {Li, Xiaohu and Saal, P. and Gan, Weimin and Landesberger, Martin and Hoelzel, Markus and Hofmann, Michael}, title = {Strain Induced Martensitic Transformation in Austempered Ductile Iron (ADI)}, volume = {746}, pages = {012055}, journal = {Journal of Physics: Conference Series}, publisher = {IOP Publishing}, address = {Bristol}, issn = {1742-6588}, doi = {https://doi.org/10.1088/1742-6596/746/1/012055}, year = {2016}, abstract = {The strain induced martensitic transformation in austempered ductile iron (ADI) has been investigated using high resolution neutron diffraction on samples compressed ex-situ to different plastic strains. In addition bulk texture measurements using neutron diffraction have been performed to calculate the orientation distribution of ferrite and austenite phases for different strain levels. Combing the detailed texture information with neutron diffraction pattern proved to be essential for quantitative phase analysis and extraction of martensite phase fractions. The martensite content induced by strain in ADI depends on austempering temperature and degree of deformation.}, language = {en} } @article{LandesbergerKoosHofmannetal.2020, author = {Landesberger, Martin and Koos, Robert and Hofmann, Michael and Li, Xiaohu and Boll, Torben and Petry, Winfried and Volk, Wolfram}, title = {Phase Transition Kinetics in Austempered Ductile Iron (ADI) with Regard to Mo Content}, volume = {13}, pages = {5266}, journal = {Materials}, number = {22}, publisher = {MDPI}, address = {Basel}, issn = {1996-1944}, doi = {https://doi.org/10.3390/ma13225266}, year = {2020}, abstract = {The phase transformation to ausferrite during austempered ductile iron (ADI) heat treatment can be significantly influenced by the alloying element Mo. Utilizing neutron diffraction, the phase transformation from austenite to ausferrite was monitored in-situ during the heat treatment. In addition to the phase volume fractions, the carbon enrichment of retained austenite was investigated. The results from neutron diffraction were compared to the macroscopic length change from dilatometer measurements. They show that the dilatometer data are only of limited use for the investigation of ausferrite formation. However, they allow deriving the time of maximum carbon accumulation in the retained austenite. In addition, the transformation of austenite during ausferritization was investigated using metallographic methods. Finally, the distribution of the alloying elements in the vicinity of the austenite/ferrite interface zone was shown by atom probe tomography (APT) measurements. C and Mn were enriched within the interface, while Si concentration was reduced. The Mo concentration in ferrite, interface and austentite stayed at the same level. The delay of austenite decay during Stage II reaction caused by Mo was studied in detail at 400 °C for the initial material as well as for 0.25 mass \% and 0.50 mass \% Mo additions.}, language = {en} } @book{Landesberger2022, author = {Landesberger, Martin}, title = {Characterization and Design of Enhanced Ductile Irons}, publisher = {Kollemosch Verlag und Kommunikation}, address = {Buch am Buchrain}, isbn = {978-3-9820746-9-6}, pages = {XVIII, 141}, year = {2022}, language = {en} } @article{LandesbergerKoosErberetal.2020, author = {Landesberger, Martin and Koos, Robert and Erber, Maximilian and Pernumian, Matteo and Masaggia, Stefano and Hoelzel, Markus and Volk, Wolfram}, title = {Phase transition and microstructure investigation of perferritic isothermed ductile iron (IDI)}, volume = {33}, journal = {International Journal of Cast Metals Research}, number = {6}, publisher = {Taylor \& Francis}, address = {London}, issn = {1364-0461}, doi = {https://doi.org/10.1080/13640461.2020.1833477}, pages = {233 -- 241}, year = {2020}, language = {en} } @article{PanzerLandesbergerLuzinetal.2025, author = {Panzer, Hannes and Landesberger, Martin and Luzin, Vladimir and Rauner, Dominik and Wolf, Daniel and Zaeh, Michael}, title = {Evaluating the predictive capabilities of part-scale residual stress simulations of PBF-LB/M up to crack formation by a comparison to neutron diffraction}, volume = {2026}, pages = {111713}, journal = {Engineering Fracture Mechanics}, number = {331}, publisher = {Elsevier}, address = {Kidlington}, issn = {0013-7944}, doi = {https://doi.org/10.1016/j.engfracmech.2025.111713}, year = {2025}, abstract = {Additive manufacturing technologies have proven to be an excellent alternative to conventional production methods, especially when geometrically complex parts and low production quantities are aimed at. Specifically, powder bed fusion of metals using a laser beam (PBF-LB/M) additionally allows for the manufacturing of mechanically highly stressable parts. However, the heat input through the laser beam into the material and an irregular cooling during the processing result in the formation of high residual stresses. These lead to form deviations outside the specified tolerances and may accumulate to an extent, at which stress-induced cracking occurs. This emphasizes the need for an accurate prediction of the residual stresses during the PBF-LB/M process with the goal of a first-time-right additive manufacturing. In this study, three specimens exhibiting high residual stress formations during PBF-LB/M were manufactured from the nickel-based superalloy Inconel 718. Afterwards, the stresses were measured by means of neutron diffraction. The results provided the validation data for a subsequent finite element simulation, representing the build-up process on a part-scale, in which the data evaluation was conducted in accordance with the measurements for a high comparability. A comparison between the simulation and the neutron diffraction results of all three specimens showed a very good agreement of the normal stresses in all three coordinate directions, both for tensile and compressive stresses. The obtained results highlight the validity of the applied simplified part-scale simulation. The latter can, therefore, be utilized to increase the process understanding of residual stress and crack formations. It can also be used to enable process parameter modifications or geometry adaptions, aiming at a first-time-right additive manufacturing.}, language = {en} }