{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,8]],"date-time":"2026-07-08T13:03:55Z","timestamp":1783515835727,"version":"3.55.0"},"reference-count":18,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2023,3,31]],"date-time":"2023-03-31T00:00:00Z","timestamp":1680220800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100012166","name":"National Key Research and Development Program of China","doi-asserted-by":"publisher","award":["2021YEB2900703"],"award-info":[{"award-number":["2021YEB2900703"]}],"id":[{"id":"10.13039\/501100012166","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100012166","name":"National Key Research and Development Program of China","doi-asserted-by":"publisher","award":["CX2022308"],"award-info":[{"award-number":["CX2022308"]}],"id":[{"id":"10.13039\/501100012166","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100012166","name":"National Key Research and Development Program of China","doi-asserted-by":"publisher","award":["62075014"],"award-info":[{"award-number":["62075014"]}],"id":[{"id":"10.13039\/501100012166","id-type":"DOI","asserted-by":"publisher"}]},{"name":"BUPT Excellent PhD Students\u2019 Foundation","award":["2021YEB2900703"],"award-info":[{"award-number":["2021YEB2900703"]}]},{"name":"BUPT Excellent PhD Students\u2019 Foundation","award":["CX2022308"],"award-info":[{"award-number":["CX2022308"]}]},{"name":"BUPT Excellent PhD Students\u2019 Foundation","award":["62075014"],"award-info":[{"award-number":["62075014"]}]},{"name":"National Natural Science Foundation of China","award":["2021YEB2900703"],"award-info":[{"award-number":["2021YEB2900703"]}]},{"name":"National Natural Science Foundation of China","award":["CX2022308"],"award-info":[{"award-number":["CX2022308"]}]},{"name":"National Natural Science Foundation of China","award":["62075014"],"award-info":[{"award-number":["62075014"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In this paper, aiming at a large infrastructure structural health monitoring network, a quaternion wavelet transform (QWT) image denoising algorithm is proposed to process original data, and a depth feedforward neural network (FNN) is introduced to extract physical information from the denoised data. A Brillouin optical time domain analysis (BOTDA)-distributed sensor system is established, and a QWT denoising algorithm and a temperature extraction scheme using FNN are demonstrated. The results indicate that when the frequency interval is less than 4 MHz, the temperature error is kept within \u00b10.11 \u00b0C, but is \u00b10.15 \u00b0C at 6 MHz. It takes less than 17 s to extract the temperature distribution from the FNN. Moreover, input vectors for the Brillouin gain spectrum with a frequency interval of no more than 6 MHZ are unified into 200 input elements by linear interpolation. We hope that with the progress in technology and algorithm optimization, the FNN information extraction and QWT denoising technology will play an important role in distributed optical fiber sensor networks for real-time monitoring of large-scale infrastructure.<\/jats:p>","DOI":"10.3390\/s23073637","type":"journal-article","created":{"date-parts":[[2023,3,31]],"date-time":"2023-03-31T08:27:27Z","timestamp":1680251247000},"page":"3637","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Quaternion Wavelet Transform and a Feedforward Neural Network-Aided Intelligent Distributed Optical Fiber Sensing System"],"prefix":"10.3390","volume":"23","author":[{"given":"Lei","family":"Fan","sequence":"first","affiliation":[{"name":"State Key Laboratory of Information Photonics and Optical Communications, School of Electronic Engineering, Beijing University of Posts and Telecommunications (BUPT), Beijing 100876, China"},{"name":"Beijing Key Laboratory of Space-Round Interconnection and Convergence, Beijing 100876, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yongjun","family":"Wang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Information Photonics and Optical Communications, School of Electronic Engineering, Beijing University of Posts and Telecommunications (BUPT), Beijing 100876, China"},{"name":"Beijing Key Laboratory of Space-Round Interconnection and Convergence, Beijing 100876, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hongxin","family":"Zhang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Information Photonics and Optical Communications, School of Electronic Engineering, Beijing University of Posts and Telecommunications (BUPT), Beijing 100876, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chao","family":"Li","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Information Photonics and Optical Communications, School of Electronic Engineering, Beijing University of Posts and Telecommunications (BUPT), Beijing 100876, China"},{"name":"Beijing Key Laboratory of Space-Round Interconnection and Convergence, Beijing 100876, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xingyuan","family":"Huang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Information Photonics and Optical Communications, School of Electronic Engineering, Beijing University of Posts and Telecommunications (BUPT), Beijing 100876, China"},{"name":"Beijing Key Laboratory of Space-Round Interconnection and Convergence, Beijing 100876, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1884-5530","authenticated-orcid":false,"given":"Qi","family":"Zhang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Information Photonics and Optical Communications, School of Electronic Engineering, Beijing University of Posts and Telecommunications (BUPT), Beijing 100876, China"},{"name":"Beijing Key Laboratory of Space-Round Interconnection and Convergence, Beijing 100876, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiangjun","family":"Xin","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Information Photonics and Optical Communications, School of Electronic Engineering, Beijing University of Posts and Telecommunications (BUPT), Beijing 100876, China"},{"name":"Beijing Key Laboratory of Space-Round Interconnection and Convergence, Beijing 100876, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,3,31]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Cardoso, R., Ramon-Tarragona, A., Louren\u00e7o, S.D.N., Mendes, J., Caruso, M., and Jommi, C. (2022). Testing and Monitoring of Earth Structures. Civ. Eng., 85\u2013111.","DOI":"10.1007\/978-3-031-05875-2_4"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Zhang, J., Sun, J., and Zhu, Z. (2011). The long term monitoring analyses of a grid structure for swimming and Diving Hall in Qingdao Sports Center. Electr. Control Eng., 4153\u20134155.","DOI":"10.1109\/ICECENG.2011.6058217"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Li, N., Feng, L., Zhou, B., Sun, X., Liang, Z., and Xie, H. (2010, January 13\u201314). A Study on a cRIO-Based Monitoring and Safety Early Warning System for Large Bridge Structures. Proceedings of the 2010 International Conference on Measuring Technology and Mechatronics Automation, Changsha, China.","DOI":"10.1109\/ICMTMA.2010.668"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1051","DOI":"10.1177\/1475921719875630","article-title":"Live-load strain evaluation of the prestressed concrete box-girder bridge using deep learning and clustering","volume":"19","author":"Zhao","year":"2020","journal-title":"Struct. Health Monit."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"251","DOI":"10.1007\/s13349-022-00635-8","article-title":"Digital modeling approach of distributional mapping from structural temperature field to temperature-induced strain field for bridges","volume":"13","author":"Zhao","year":"2023","journal-title":"J. Civ. Struct. Health Monit."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"131","DOI":"10.1016\/j.sna.2017.03.017","article-title":"Recent progress of using Brillouin distributed fiber optic sensors for geotechnical health monitoring","volume":"258","author":"Hong","year":"2017","journal-title":"Sens. Actuators A Phys."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Barrias, A., Casas, J.R., and Villalba, S. (2016). A review of distributed optical fiber sensors for civil engineering applications. Sensors, 16.","DOI":"10.3390\/s16050748"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1134","DOI":"10.1109\/JLT.2011.2168599","article-title":"Reduction in the number of averages required in BOTDA sensors using wavelet denoising techniques","volume":"30","author":"Farahani","year":"2012","journal-title":"J. Lightw. Technol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"295","DOI":"10.1049\/iet-opt.2018.5163","article-title":"Dynamic range enhancement of OTDR using lifting wavelet transform-modified particle swarm optimisation scheme","volume":"13","author":"Tangudu","year":"2019","journal-title":"IET Optoelectron."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"10870","DOI":"10.1038\/ncomms10870","article-title":"Intensifying the response of distributed optical fibre sensors using 2D and 3D image restoration","volume":"7","author":"Soto","year":"2016","journal-title":"Nat. Commun."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"5126","DOI":"10.1364\/OE.26.005126","article-title":"Brillouin optical time domain analyzer sensors assisted by advanced image denoising techniques","volume":"26","author":"Wu","year":"2018","journal-title":"Opt. Express"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"2648","DOI":"10.1109\/JLT.2018.2876909","article-title":"Real-Time Denoising of Brillouin Optical Time Domain Analyzer with High Data Fidelity Using Convolutional Neural Networks","volume":"37","author":"Wu","year":"2019","journal-title":"J. Lightw. Technol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"2530","DOI":"10.1364\/OE.27.002530","article-title":"Deep neural networks assisted BOTDA for simultaneous temperature and strain measurement with enhanced accuracy","volume":"27","author":"Wang","year":"2019","journal-title":"Opt. Express"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Fan, L., Wang, Y., Zhang, H., Li, C., and Xin, X. (2022). High-Accuracy 3D Contour Measurement by Using the Quaternion Wavelet Transform Image Denoising Technique. Electronics, 11.","DOI":"10.3390\/electronics11121807"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"3333","DOI":"10.1109\/JIOT.2021.3098021","article-title":"Distributed Optical Fiber Sensing System for Large Infrastructure Temperature Monitoring","volume":"9","author":"Wang","year":"2022","journal-title":"IEEE Internet Things J."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"31347","DOI":"10.1364\/OE.21.031347","article-title":"Modeling and evaluating the performance of Brillouin distributed optical fiber sensors","volume":"21","author":"Soto","year":"2013","journal-title":"Opt. Express"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1842","DOI":"10.1109\/50.633570","article-title":"Brillouin Gain Spectrum Characterization in Single-Mode Optical Fibers","volume":"15","author":"Robert","year":"1997","journal-title":"J. Lightw. Technol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"26","DOI":"10.1364\/OL.29.000026","article-title":"Comparison of the methods for discriminating temperature and strain in spontaneous Brillouin-based distributed sensors","volume":"29","author":"Alahbabi","year":"2004","journal-title":"Opt. Lett."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/7\/3637\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T19:08:02Z","timestamp":1760123282000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/7\/3637"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,3,31]]},"references-count":18,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2023,4]]}},"alternative-id":["s23073637"],"URL":"https:\/\/doi.org\/10.3390\/s23073637","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,3,31]]}}}