TY - JOUR A1 - Karapanagiotis, Christos A1 - Krebber, Katerina T1 - Machine Learning Approaches in Brillouin Distributed Fiber Optic Sensors N2 - This paper presents reported machine learning approaches in the field of Brillouin distributed fiber optic sensors (DFOSs). The increasing popularity of Brillouin DFOSs stems from their capability to continuously monitor temperature and strain along kilometer-long optical fibers, rendering them attractive for industrial applications, such as the structural health monitoring of large civil infrastructures and pipelines. In recent years, machine learning has been integrated into the Brillouin DFOS signal processing, resulting in fast and enhanced temperature, strain, and humidity measurements without increasing the system’s cost. Machine learning has also contributed to enhanced spatial resolution in Brillouin optical time domain analysis (BOTDA) systems and shorter measurement times in Brillouin optical frequency domain analysis (BOFDA) systems. This paper provides an overview of the applied machine learning methodologies in Brillouin DFOSs, as well as future perspectives in this area. KW - Distributed fiber optic sensors KW - BOTDA KW - BOFDA KW - Machine learning KW - Strain and temperature measurements KW - Artificial neural networks PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-580145 DO - https://doi.org/10.3390/s23136187 VL - 23 IS - 13 SP - 1 EP - 26 PB - MDPI AN - OPUS4-58014 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Karapanagiotis, Christos A1 - Hicke, Konstantin A1 - Krebber, Katerina T1 - Machine learning assisted BOFDA for simultaneous temperature and strain sensing in a standard optical fiber N2 - We report, to our knowledge for the first time on simultaneous distributed temperature and strain sensing in a standard telecom optical fiber using a machine learning assisted Brillouin frequency domain analysis (BOFDA) system. The well-known temperature and strain cross-sensitivity problem is addressed by developing a BOFDA system with a high signal-to-noise ratio and applying machine learning. The spectrum consists of four highly resolved peaks, whose Brillouin frequency shifts are extracted and serve as features for the machine learning algorithms. The spectra result from a 450-m standard SMF-28 optical fiber, and particularly from a segment of 30 m. This fiber segment is coiled around a stretcher and placed in a climate chamber. The applied temperature and strain values range from 20 °C to 40 °C and from 0 µɛ to 1380 µɛ, respectively. The total measurement time to achieve a high SNR and resolve four peaks with a spatial resolution of 6 m is 16 min. To discriminate temperature and strain effects, simple frequentist and more sophisticated Bayesian-based algorithms are employed with the powerful Gaussian process regression (GPR) delivering the best performance in terms of temperature and strain errors, which are found to be 2 °C and 45 µɛ, respectively. These errors are calculated using leave-one-out cross-validation, so that an unbiased estimation of the sensor’s performance is provided. KW - Machine learning KW - Brillouin distributed fiber optic sensors KW - Temperature and strain sensing KW - BOFDA PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569155 DO - https://doi.org/10.1364/OE.480224 SN - 1094-4087 VL - 31 IS - 3 SP - 5027 EP - 5041 PB - OPTICA AN - OPUS4-56915 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Karapanagiotis, Christos T1 - Evaluation of the generalization performance of a CNN-assisted BOFDA system N2 - Brillouin Optical Frequency Domain Analysis (BOFDA) is a powerful and well-established method for static distributed sensing of temperature and strain. Recently, we demonstrated a BOFDA system based on convolutional neural network which shortens the measurement time considerably. In this paper, we apply leave-one-out cross validation to evaluate the generalization performance and provide an unbiased and reliable machine learning model for a time-efficient BOFDA system. T2 - 21. ITG/GMA Fachtagung Sensoren und Messsysteme 2022 CY - Nuremberg, Germany DA - 10.05.2022 KW - Fiber optics sensors KW - BOFDA KW - Brillouin distributed sensing KW - Machine learning PY - 2022 UR - https://www.ama-science.org/direct/tagungsband-sensoren-und-messsysteme-2022 SN - 978-3-8007-5835-7 SP - 289 EP - 292 PB - VDE VERLAG GMBH AN - OPUS4-55183 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wosniok, Aleksander T1 - Brillouin optical frequency-domain analysis for structural health monitoring N2 - We present our achievements in the development of distributed fiber optic sensing systems based on Brillouin optical frequency-domain analysis for structural health monitoring. The focus of the applications is on the gapless monitoring of geotechnical structures, large area infrastructures and electrical grids. The work includes the latest use of machine learning algorithms to reduce measurement time by coexistent increasing the measurement accuracy. T2 - 4th Workshop on Optomechanics and Brillouin Scattering CY - Erlangen, Germany DA - 14.06.2022 KW - Distributed sensing KW - BOFDA KW - Optical fiber sensor KW - Brillouin distributed fiber sensor PY - 2022 AN - OPUS4-55173 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Karapanagiotis, Christos T1 - Evaluation of the generalization performance of a CNN-assisted BOFDA system N2 - Brillouin Optical Frequency Domain Analysis (BOFDA) is a powerful and well-established method for static distributed sensing of temperature and strain. Recently, we demonstrated a BOFDA system based on convolutional neural network which shortens the measurement time considerably. In this paper, we apply leave-one-out cross validation to evaluate the generalization performance and provide an unbiased and reliable machine learning model for a time-efficient BOFDA system. T2 - 21. ITG/GMA Fachtagung Sensoren und Messsysteme 2022 CY - Nürnberg, Germany DA - 10.05.2022 KW - Fiber optics sensors KW - BOFDA KW - Convolutional neural networks KW - Machine learning KW - Temperature sensing PY - 2022 AN - OPUS4-54862 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Karapanagiotis, Christos A1 - Hicke, Konstantin A1 - Krebber, Katerina T1 - Temperature and humidity discrimination in Brillouin distributed fiber optic sensing using machine learning algorithms N2 - In the last few years, the use of machine learning has emerged in the field of distributed fiber optic sensors as a promising approach to enhance their performance and provide new capabilities. In this study, we use machine learning for simultaneous measurements of temperature and humidity in polyimide (PI)-coated optical fibers based on Brillouin Brillouin optical frequency domain analysis (BOFDA). Different non-linear machine learning algorithms are employed, namely polynomial regression, decision trees and artificial neural networks (ANNs), and their discrimination performance is benchmarked against that of the conventional linear regression. The performance is evaluated using leave-one-out cross-validation to ensure that the models are reliable and able to generalize well on new data. We show that nonlinear machine learning algorithms outperform the conventional linear regression and thus could pave the way towards simultaneous cost-effective temperature and humidity distributed sensing, which has the potential to find attractive new applications in the field of civil and geotechnical engineering, from structural health monitoring of dikes and bridges to subsea cables and long pipelines corrosion detection. T2 - SPIE Photonics Europe 2022 CY - Strasbourg, France DA - 03.04.2022 KW - Distributed Brillouin sensing KW - Machine learning KW - Artificial neural networks KW - Simultaneous temperature and humidity sensing KW - BOFDA PY - 2022 DO - https://doi.org/10.1117/12.2620985 VL - 12139 SP - 1 EP - 7 PB - SPIE AN - OPUS4-54861 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - THES A1 - Schreier, Andy T1 - Distributed Brillouin sensor in polymer optical fibers utilizing BOFDA N2 - In this thesis, a distributed Brillouin sensor in perfluorinated polymer optical fibers utilizing BOFDA is presented. These commercially available polymer fibers offer beneficial characteristics for sensing applications such as higher break down strain up to 100 %, minimal bending radii below 2 mm, higher sensitivity to temperature and lower sensitivity to strain compared to their silica equivalent. The chosen wavelength of operation at 1319 nm corresponds to lower fiber propagation loss (< 37 dB/km) compared to other approaches at 1550 nm (150 - 250 dB/km). A 86 m PFGI-POF was successfully measured by BOFDA with spatial resolution of 3.4 m. The findings related to humidity influences can serve as a basis for future distributed humidity sensors not only limited to stimulated Brillouin backscattering. KW - BOFDA KW - Polymer optical fiber KW - POF KW - Brillouin sensor KW - Distributed sensor PY - 2020 SN - 978-3-7369-7146-2 SP - 1 EP - 116 PB - Cuvillier Verlag Göttingen CY - Göttingen AN - OPUS4-51041 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wosniok, Aleksander A1 - Schreier, Andy A1 - Krebber, Katerina T1 - Distributed BOFDA measurement on an 86 m long perfluorinated polymer optical fiber N2 - We present our research on the development of a Brillouin optical frequency-domain analysis (BOFDA) using a perfluorinated graded-index polymer optical fiber (PFGI-POF) as a sensing fiber. The described works include investigations both on the selection of the setup components with respect to mode coupling effects and on the impact of the humidity cross-sensitivity. The suitability of the developed POF-based BOFDA is proved by a distributed measurement on an 86 m long PFGI-POF recorded with the spatial resolution of 6 m. T2 - 28th International Conference on Plastic Optical Fibers CY - Yokohama, Japan DA - 20.11.2019 KW - Brillouin sensing KW - BOFDA KW - Perfluorinated graded-index polymer optical fiber KW - PFGI-POF PY - 2019 SP - 27 EP - 28 AN - OPUS4-49865 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wosniok, Aleksander T1 - Distributed BOFDA measurement on an 86 m long perfluorinated polymer optical fiber N2 - We present our research on the development of a Brillouin optical frequency-domain analysis (BOFDA) using a perfluorinated graded-index polymer optical fiber (PFGI-POF) as a sensing fiber. The described works include investigations both on the selection of the setup components with respect to mode coupling effects and on the impact of the humidity cross-sensitivity. The suitability of the developed POF-based BOFDA is proved by a distributed measurement on an 86 m long PFGI-POF recorded with the spatial resolution of 6 m. T2 - 28th International Conference on Plastic Optical Fibers CY - Yokohama, Japan DA - 20.11.2019 KW - Brillouin sensing KW - BOFDA KW - Perfluorinated graded-index polymer optical fiber KW - PFGI-POF PY - 2019 AN - OPUS4-49866 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Wosniok, Aleksander ED - Peng, G.D. T1 - Distributed Brillouin Sensing: Frequency-Domain Techniques N2 - The substantial progresses in fiber-optic communications in combination with the increasing economic and political interest in structural health monitoring have led to a commercial establishment of distributed Brillouin sensing. The sensor systems, mainly based on the time-domain techniques, have been successfully implemented in the areas such as pipeline leak detection, geohazard effects, and ground movement detection. This chapter introduces a further advancement in the area of Brillouin sensing in the frequency domain. The so-called Brillouin optical frequency-domain analysis (BOFDA) offers crucial perspectives in terms of dynamic range and cost efficiency. The main principle of the frequency-domain approach takes advantage of the reversibility between the time and frequency domain given by a Fourier transform in the analysis of linear systems. The hereby presented overview gives a summary of the benefits and challenges of frequency-domain measurements closely tied to the narrowband recording of the complex transfer function. This function relates the counterpropagating pump and probe laser light along the sensor fiber providing the pulse response of the measurement system by applying the inverse Fourier transform (IFT). The strain or temperature distribution can be then determined from the retrieved Brillouin frequency shift (BFS) profile along the fiber. KW - Distributed Brillouin Sensing KW - Brillouin optical frequency-domain analysis KW - BOFDA PY - 2018 SN - 978-981-10-1477-2 DO - https://doi.org/10.1007/978-981-10-1477-2_8-1 VL - 2018 SP - 1 EP - 25 PB - Springer Nature CY - Singapore AN - OPUS4-45044 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Habel, Wolfgang A1 - Krebber, Katerina T1 - Application of fiber-optic sensors for health monitoring purposes in geo-engineering T2 - 4th International forum on opto-electronic sensor-based monitoring in geo-engineering CY - Suzhou, China DA - 2012-10-11 KW - BOFDA KW - Fibre-optic sensor KW - Distributed sensor KW - Brillouin sensor KW - Polymer optical fibers (POF) KW - POF sensor KW - POF OTDR KW - Strain sensor KW - Technical textiles KW - Geotextiles KW - Geophone KW - Fabry-Perot sensor KW - Pile test KW - Impact KW - Acoustic wave PY - 2012 SP - 4 EP - 15 AN - OPUS4-27259 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wosniok, Aleksander ED - Liao, Y. ED - Jin, W. ED - Sampson, D.D. ED - Yamauchi, R. ED - Chung, Y. ED - Nakamura, K. ED - Rao, Y. T1 - Brillouin gain spectrum characteristics for temperature compensation in fiber optic distributed strain sensor N2 - We studied Brillouin gain spectrum characteristics in single-mode optical fibers with different refractive index profiles to realize temperature-corrected distributed strain measurement. The measured Brillouin frequency shift (BFS) features much stronger dependence on the longitudinal strain in the sensor fiber than on the temperature distribution along the fiber optic sensor. By detection of slight structural changes in monitored civil structures, such as dams, pipelines and tunnels, the influence of temperature on the measured BFS cannot be neglected. T2 - OFS2012 - 22nd International conference on optical fiber sensors CY - Beijing, China DA - 15.10.2012 KW - Brillouin gain spectrum KW - BGS KW - Distributed Brillouin sensor KW - DBS KW - Fibre optic sensor KW - FOS KW - Brillouin optical frequency-domain analysis KW - BOFDA PY - 2012 DO - https://doi.org/10.1117/12.974841 SN - 0277-786X SN - 1996-756X N1 - Serientitel: Proceedings of SPIE – Series title: Proceedings of SPIE IS - 8421 SP - 84219T-1 EP - 84219T-4 PB - SPIE, the International Society for Optical Engineering CY - Bellingham, Wash. AN - OPUS4-26978 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wosniok, Aleksander A1 - Krebber, Katerina T1 - Simultaneous measurement of temperature and strain distribution using Brillouin scattering in dispersion-shifted fibers N2 - We studied Brillouin gain spectrum characteristics in dispersion-shifted fibers having compound GeO2-doping compositions in the fiber core to realize simultaneous measurement of distributed strain and temperature. Due to various dopant concentration alongside the radius of tested nonzero dispersion-shifted fibers several multiple Brillouin scattering resonances were observed in the stimulated Brillouin spectra arose through backscattering on higher acoustic modes which propagated along the fiber axis. As a result of the varying acoustic velocities, the Brillouin resonance peaks featured different temperature coefficients which can be used to accomplish the simultaneous measurement of fiber strain and temperature. We presented our first measurement results for NZDS Fujikura and LEAF Corning fiber and discussed the superior sensory suitability of the former fiber types. T2 - IEEE Sensors 2011 conference CY - Limerick, Ireland DA - 28.10.2011 KW - Fiber optic sensor KW - Spatial distributed sensor KW - Brillouin gain spectrum (BGS) KW - Nonzero dispersion-shifted fiber (NZDSF) KW - Brillouin sensor KW - BOTDA KW - BOFDA PY - 2011 SN - 978-1-4244-9288-6 SP - 1476 EP - 1479 AN - OPUS4-24828 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Glötzl, R. A1 - Schneider Glötzl, J. A1 - Wosniok, Aleksander A1 - Krebber, Katerina A1 - Krywult, L. ED - Wintera, J. ED - Kosik, A. ED - Wity, A. T1 - Optical distributed sensing systems and possible applications in geotechnical measuring N2 - In comparison with traditional measuring Systems (pressure cells, piezometers and inclinometers which produce only point measurements) fibre optic sensors are well suited for spatiallydistributed monitoring purposes. The very tiny optical fibres of a diameter of less then 1 mm can operate as sensors in strong electromagnetic fields, under “harsh” explosive and Chemical environments and under ionizing radiation. T2 - XIV Dam monitoring international conference 'safetyof dams - new challenges' ('Bezpieczenstwo zapór - nowe wyzwania') CY - Walbrzych, Poland DA - 13.06.2011 KW - Fibre optic sensor KW - Spatial distributed sensor KW - Polymer optical fibre (POF) KW - Glass optical fibre (GOF) KW - POF OTDR KW - Brillouin sensor KW - BOTDA KW - BOFDA KW - Fibre Bragg grating (FBG) KW - Geosynthetics KW - Geotxtiles KW - Technical textiles PY - 2011 SN - 978-83-61102-53-3 N1 - Serientitel: Monografie - Instytutu Meteorologii i Gospodarki Wodnej – Series title: Monografie - Instytutu Meteorologii i Gospodarki Wodnej IS - Chapter 6 SP - 173 EP - 180 AN - OPUS4-24066 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wosniok, Aleksander A1 - Krywult, L. A1 - Liehr, Sascha A1 - Krebber, Katerina A1 - Wendt, Mario A1 - Chrost, A. T1 - Monitoring konstrukcji ziemnych przy zastosowaniu rozlozonych przestrzennie swiatlowodowych sensorów optycznych, zintegrowanych w geosyntetykach KW - Fibre optic sensor KW - Spatial distributed sensor KW - Polymer optical fibre (POF) KW - Glass optical fibre (GOF) KW - POF OTDR KW - Brillouin sensor KW - BOTDA KW - BOFDA KW - Fibre Bragg grating (FBG) KW - Geosynthetics KW - Geotextiles KW - Technical textiles PY - 2011 UR - http://journals.bg.agh.edu.pl/GORNICTWO/2011-02/GG_2011_2_63.pdf SN - 1732-6702 SN - 0138-0990 VL - 35 IS - 2 SP - 597 EP - 604 PB - Uczelniane Wydawn. Naukowo-Dydaktyczne AGH CY - Kraków AN - OPUS4-23418 LA - pol AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kasinathan, Murugesan A1 - Rao, C.B. A1 - Murali, N. A1 - Jayakumar, T. A1 - Raj, B. A1 - Wosniok, Aleksander A1 - Krebber, Katerina T1 - Analysis of stimulated Brillouin scattering characteristics in frequency domain T2 - ICOP 2009 - International conference on optics & photonics CY - Chandigarh, India DA - 2009-10-30 KW - BOFDA KW - Fibre optic sensors KW - Distributed Brillouin sensors KW - Stimulated Brillouin scattering KW - Nonlinear optics PY - 2009 SP - 1 EP - 5(?) AN - OPUS4-21150 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wosniok, Aleksander A1 - Nöther, Nils A1 - Krebber, Katerina ED - Juergen Brugger, ED - Danick Briand, T1 - Distributed fibre optic sensor system for temperature and strain monitoring based on Brillouin optical-fibre frequency-domain analysis T2 - EUROSENSORS XXIII: sensors, actuators and micro/nanosystems CY - Lausanne, Switzerland DA - 2009-09-06 KW - BOFDA KW - Sideband technique KW - Fibre optic sensors KW - Distributed Brillouin sensors KW - Stimulated Brillouin scattering KW - Nonlinear optics PY - 2009 SN - 1876-6196 SP - 1 EP - 4(?) AN - OPUS4-20235 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Nöther, Nils A1 - Wosniok, Aleksander A1 - Krebber, Katerina ED - Francis Berghmans, ED - Mignani, Anna Grazia ED - Cutolo, Antonello ED - Patrick P. Meyrueis, ED - Thomas P. Pearsall, T1 - A distributed fiber optic sensor system for dike monitoring using Brillouin frequency domain analysis T2 - Optical Sensors 2008, April 7-10, 2008 CY - Strasbourg, France DA - 2008-04-07 KW - BOFDA KW - Brillouin sensing KW - Distributed strain measurement KW - Dike monitoring KW - Sensor-based geotextiles KW - Fibre optic sensors KW - Distributed sensors KW - Brillouin scattering PY - 2008 SN - 978-0-8194-7201-4 SN - 0277-786X N1 - Serientitel: Proceedings of SPIE – Series title: Proceedings of SPIE IS - 7003 SP - 700303-1 - 700303-9 PB - SPIE CY - Bellingham AN - OPUS4-18274 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Nöther, Nils A1 - Wosniok, Aleksander A1 - Krebber, Katerina A1 - Thiele, E. ED - Ecke, Wolfgang ED - Kara J. Peters, ED - Norbert G. Meyendorf, T1 - A distributed fiber optic sensor system for dike monitoring using Brillouin optical frequency domain analysis N2 - We report on the development of a complete system for spatially resolved detection of critical soil displacement in river embankments. The system uses Brillouin frequency domain analysis (BOFDA) for distributed measurement of strain in silica optical fibers. Our development consists of the measurement unit, an adequate coating for the optical fibers and a technique to integrate the coated optical fibers into geotextiles as they are commonly used in dike construction. We present several laboratory and field tests that prove the capability of the system to detect areas of soil displacement as small as 2 meters. These are the first tests of truly distributed strain measurements on optical fibers embedded into geosynthetics. T2 - Smart Sensor Phenomena, Technology, Networks, and Systems 2008 CY - San Diego, California, USA DA - 2008-03-10 KW - BOFDA KW - Brillouin sensing KW - Distributed strain measurement KW - Dike monitoring KW - Sensor-based geotextiles KW - Fiber optic sensors KW - Distributed sensors KW - Brillouin scattering PY - 2008 SN - 978-0-8194-7119-2 DO - https://doi.org/10.1117/12.775133 SN - 0277-786X N1 - Serientitel: Proceedings of SPIE – Series title: Proceedings of SPIE IS - 6933 SP - 69330T-1 - 69330T-9 PB - SPIE CY - Bellingham AN - OPUS4-18250 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -