{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,29]],"date-time":"2026-04-29T23:57:18Z","timestamp":1777507038887,"version":"3.51.4"},"reference-count":72,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2022,5,29]],"date-time":"2022-05-29T00:00:00Z","timestamp":1653782400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Metals"],"abstract":"<jats:p>Ultrasonic guided wave testing (UGWT) is a non-destructive testing (NDT) technique commonly used in structural health monitoring to perform wide-range inspection from a single point, thus reducing the time and effort required for NDT. However, the multi-modal and dispersive nature of guided waves makes the extraction of essential information that leads to defect detection an extremely challenging task. The purpose of this article is to give an overview of signal processing techniques used for filtering signals, isolating modes and identifying and localising defects in UGWT. The techniques are summarised and grouped according to the geometry of the studied structures. Although the reviewed techniques have led to satisfactory results, the identification of defects through signal processing remains challenging with space for improvement, particularly by combining signal processing techniques and integrating machine learning algorithms.<\/jats:p>","DOI":"10.3390\/met12060936","type":"journal-article","created":{"date-parts":[[2022,5,29]],"date-time":"2022-05-29T23:43:03Z","timestamp":1653867783000},"page":"936","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":60,"title":["A Review of Signal Processing Techniques for Ultrasonic Guided Wave Testing"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8477-9845","authenticated-orcid":false,"given":"Ana Rita","family":"Diogo","sequence":"first","affiliation":[{"name":"Departamento de F\u00edsica e Astronomia, Falculdade de Ci\u00eancias, Universidade do Porto, 4169-007 Porto, Portugal"}]},{"given":"Bruno","family":"Moreira","sequence":"additional","affiliation":[{"name":"EQS Global, 4470-211 Maia, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0935-9266","authenticated-orcid":false,"given":"Carlos A. J.","family":"Gouveia","sequence":"additional","affiliation":[{"name":"EQS Global, 4470-211 Maia, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7603-6526","authenticated-orcid":false,"given":"Jo\u00e3o Manuel R. S.","family":"Tavares","sequence":"additional","affiliation":[{"name":"Instituto de Ci\u00eancia e Inova\u00e7\u00e3o em Engenharia Mec\u00e2nica e Engenharia Industrial, Departamento de Engenharia Mec\u00e2nica, Faculdade de Engenharia, Universidade do Porto, 4200-465 Porto, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2022,5,29]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Rose, J.L. (2014). Ultrasonic Guided Waves in Solid Media, Cambridge University Press.","DOI":"10.1017\/CBO9781107273610"},{"key":"ref_2","first-page":"66","article-title":"Practical long range guided wave inspection-applications to pipes and rail","volume":"61","author":"Cawley","year":"2003","journal-title":"Mater. Eval."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/S0963-8695(00)00024-4","article-title":"The effect of dispersion on long-range inspection using ultrasonic guided waves","volume":"34","author":"Wilcox","year":"2001","journal-title":"NDT E Int."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Liu, S., Ding, J., and Wang, S. (2021, January 13\u201315). Application of ultrasonic guided wave testing for overhead pipelines in service. Proceedings of the ASME 2021 Pressure Vessels & Piping Conference, Virtual, Online.","DOI":"10.1115\/PVP2021-60816"},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Mahal, H., Yang, K., and Nandi, A. (2019). Defect detection using power spectrum of torsional waves in guided-wave inspection of pipelines. Appl. Sci., 9.","DOI":"10.3390\/app9071449"},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Rostami, J., Tse, P., and Fang, Z. (2017). Sparse and dispersion-based matching pursuit for minimizing the dispersion effect occurring when using guided wave for pipe inspection. Materials, 10.","DOI":"10.3390\/ma10060622"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"903","DOI":"10.1098\/rspa.1998.0193","article-title":"The Empirical Mode Decomposition and the Hilbert Spectrum for Nonlinear and Non-Stationary Time Series Analysis","volume":"454","author":"Huang","year":"1998","journal-title":"Proc. Math. Phys. Eng. Sci."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"2669","DOI":"10.1121\/1.426883","article-title":"Time-frequency analysis of the dispersion of Lamb modes","volume":"105","author":"Prosser","year":"2000","journal-title":"J. Acoust. Soc. Am."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1841","DOI":"10.1121\/1.1357813","article-title":"Time-frequency representations of Lamb waves","volume":"109","author":"Niethammer","year":"2001","journal-title":"J. Acoust. Soc. Am."},{"key":"ref_10","first-page":"342","article-title":"Review of signal processing in ultrasonic guided waves nondestructive testing","volume":"33","author":"Wu","year":"2007","journal-title":"Beijing Gongye Daxue Xuebao J. Beijing Univ. Technol."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"484","DOI":"10.1109\/TNS.2004.843121","article-title":"Structural integrity monitoring of steam generator tubing using transient acoustic signal analysis","volume":"52","author":"Lu","year":"2005","journal-title":"IEEE Trans. Nucl. Sci."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Ghavamian, A., Mustapha, F., Baharudin, B., and Yidris, N. (2018). Detection, localisation and assessment of defects in pipes using guided wave techniques: A review. Sensors, 18.","DOI":"10.3390\/s18124470"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"20190581","DOI":"10.1098\/rsta.2019.0581","article-title":"Machine learning at the interface of structural health monitoring and non-destructive evaluation: Machine Learning in SHM and NDE","volume":"378","author":"Gardner","year":"2020","journal-title":"Philos. Trans. R. Soc. A Math. Phys. Eng. Sci."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Olisa, S.C., Khan, M.A., and Starr, A. (2021). Review of Current Guided Wave Ultrasonic Testing (GWUT) Limitations and Future Directions. Sensors, 21.","DOI":"10.3390\/s21030811"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"535","DOI":"10.1016\/S0041-624X(02)00249-4","article-title":"Flaw localization using the reassigned spectrogram on laser-generated and detected Lamb modes","volume":"39","author":"Valle","year":"2002","journal-title":"Ultrasonics"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"419","DOI":"10.1109\/TUFFC.2003.1197965","article-title":"A rapid signal processing technique to remove the effect of dispersion from guided wave signals","volume":"50","author":"Wilcox","year":"2003","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"301","DOI":"10.1016\/S0041-624X(02)00455-9","article-title":"Hidden corrosion detection in aircraft aluminum structures using laser ultrasonics and wavelet transform signal analysis","volume":"41","author":"Silva","year":"2003","journal-title":"Ultrasonics"},{"key":"ref_18","first-page":"444","article-title":"Study of ultrasonic guided waves signal based on morphology component analysis method","volume":"41","author":"Li","year":"2013","journal-title":"Tien Tzu Hsueh Pao\/Acta Electron. Sin."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"403","DOI":"10.1177\/1475921710379520","article-title":"Time-varying inverse filtering of narrowband ultrasonic signals","volume":"10","author":"Moll","year":"2011","journal-title":"Struct. Health Monit."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"611","DOI":"10.1121\/1.1582439","article-title":"The reflection of the fundamental torsional mode from cracks and notches in pipes","volume":"114","author":"Demma","year":"2003","journal-title":"J. Acoust. Soc. Am."},{"key":"ref_21","first-page":"7283450","article-title":"A Signal Decomposition Method for Ultrasonic Guided Wave Generated from Debonding Combining Smoothed Pseudo Wigner-Ville Distribution and Vold-Kalman Filter Order Tracking","volume":"2017","author":"Wu","year":"2017","journal-title":"Shock Vib."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1623","DOI":"10.1016\/j.ymssp.2008.01.003","article-title":"Damage identification by wavelet analysis","volume":"22","author":"Grabowska","year":"2008","journal-title":"Mech. Syst. Signal Process."},{"key":"ref_23","first-page":"480","article-title":"Advances in defect characterisation using long-range ultrasonic testing of pipes","volume":"50","author":"Catton","year":"2008","journal-title":"Insight Non-Destr. Test. Cond. Monit."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"222","DOI":"10.1016\/j.ndteint.2008.09.011","article-title":"Application of laser-generated guided wave for evaluation of corrosion in carbon steel pipe","volume":"42","author":"Lee","year":"2009","journal-title":"NDT E Int."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1525","DOI":"10.1121\/1.4788984","article-title":"Model-based imaging of damage with Lamb waves via sparse reconstruction","volume":"133","author":"Levine","year":"2013","journal-title":"J. Acoust. Soc. Am."},{"key":"ref_26","first-page":"111","article-title":"Application of improved matching pursuit method in guided wave signal processing","volume":"32","author":"Li","year":"2012","journal-title":"Zhendong Ceshi Yu Zhenduan J. Vib. Meas. Diagn."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"753","DOI":"10.1016\/j.engappai.2006.05.005","article-title":"A signal-processing tool for non-destructive testing of inaccessible pipes","volume":"19","author":"Cau","year":"2006","journal-title":"Eng. Appl. Artif. Intell."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Mahal, H., Yang, K., and Nandi, A. (2019). Improved defect detection using adaptive leaky NLMS filter in guided-wave testing of pipelines. Appl. Sci., 9.","DOI":"10.3390\/app9020294"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"48","DOI":"10.1016\/j.ultras.2017.08.002","article-title":"Split-spectrum processing technique for SNR enhancement of ultrasonic guided wave","volume":"83","author":"Pedram","year":"2018","journal-title":"Ultrasonics"},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Pedram, S., Gan, T.H., and Ghafourian, M. (2020). Improved defect detection of guided wave testing using split-spectrum processing. Sensors, 20.","DOI":"10.3390\/s20174759"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"42","DOI":"10.1016\/j.renene.2017.03.052","article-title":"Wavelet transforms and pattern recognition on ultrasonic guides waves for frozen surface state diagnosis","volume":"116","year":"2018","journal-title":"Renew. Energy"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"2307","DOI":"10.1007\/s11012-016-0581-1","article-title":"Noise processing of flaw reconstruction by wavelet transform in ultrasonic guided SH waves","volume":"52","author":"Da","year":"2017","journal-title":"Meccanica"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"118","DOI":"10.3901\/JME.2008.07.118","article-title":"Application of wavelet denoise in defect inspection of steel strands","volume":"44","author":"He","year":"2008","journal-title":"Jixie Gongcheng Xuebao Chin. J. Mech. Eng."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"176","DOI":"10.1016\/j.measurement.2017.06.038","article-title":"The design of a novel mother wavelet that is tailor-made for continuous wavelet transform in extracting defect-related features from reflected guided wave signals","volume":"110","author":"Chen","year":"2017","journal-title":"Meas. J. Int. Meas. Confed."},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Tiwari, K., Raisutis, R., and Samaitis, V. (2017). Hybrid signal processing technique to improve the defect estimation in ultrasonic non-destructive testing of composite structures. Sensors, 17.","DOI":"10.3390\/s17122858"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"2","DOI":"10.1016\/j.ress.2018.02.013","article-title":"Dirt and mud detection and diagnosis on a wind turbine blade employing guided waves and supervised learning classifiers","volume":"184","year":"2019","journal-title":"Reliab. Eng. Syst. Saf."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Wang, G., Wang, Y., Sun, H., Miao, B., and Wang, Y. (2019). A reference matching-based temperature compensation method for ultrasonic guided wave signals. Sensors, 19.","DOI":"10.3390\/s19235174"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"095601","DOI":"10.1088\/1361-6501\/abef3c","article-title":"An advanced Wigner-Ville time-frequency analysis of Lamb wave signals based upon an autoregressive model for efficient damage inspection","volume":"32","author":"Rizvi","year":"2021","journal-title":"Meas. Sci. Technol."},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Lee, Y., and Cho, Y. (2021). Defect imaging enhancement through optimized shape factors of the rapid algorithm based on guided wave beam pattern analysis. Sensors, 21.","DOI":"10.3390\/s21124029"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"217","DOI":"10.1016\/j.neucom.2012.11.053","article-title":"2-D defect profile reconstruction from ultrasonic guided wave signals based on QGA-kernelized ELM","volume":"128","author":"Liu","year":"2014","journal-title":"Neurocomputing"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"532","DOI":"10.1016\/j.measurement.2017.06.033","article-title":"Detection of Minor Damage in Structures with Guided Wave Signals and Nonlinear Oscillator","volume":"122","author":"Zhang","year":"2017","journal-title":"Measurement"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"1692","DOI":"10.1109\/PROC.1975.10036","article-title":"Adaptive noise cancelling: Principles and applications","volume":"63","author":"Widrow","year":"1975","journal-title":"Proc. IEEE"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"468","DOI":"10.1109\/TAES.1968.5409001","article-title":"A Quantitative Analysis of Sea Clutter Decorrelation with Frequency Agility","volume":"AES-4","author":"Beasley","year":"1968","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1016\/0041-624X(82)90003-8","article-title":"Flaw-to-grain echo enhancement by split-spectrum processing","volume":"20","author":"Newhouse","year":"1982","journal-title":"Ultrasonics"},{"key":"ref_45","doi-asserted-by":"crossref","unstructured":"Mahal, H., Yang, K., and Nandi, A. (2018). Detection of defects using spatial variances of guided-wave modes in testing of pipes. Appl. Sci., 8.","DOI":"10.3390\/app8122378"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"331","DOI":"10.1007\/BF01456326","article-title":"Zur Theorie der orthogonalen Funktionensysteme","volume":"69","author":"Haar","year":"1910","journal-title":"Math. Ann."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"3397","DOI":"10.1109\/78.258082","article-title":"Matching pursuits with time-frequency dictionaries","volume":"41","author":"Mallat","year":"1993","journal-title":"IEEE Trans. Signal Process."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"749","DOI":"10.1103\/PhysRev.40.749","article-title":"On the Quantum Correction For Thermodynamic Equilibrium","volume":"40","author":"Wigner","year":"1932","journal-title":"Phys. Rev."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"102150","DOI":"10.1016\/j.ndteint.2019.102150","article-title":"Corrosion detection in steel bar: A time-frequency approach","volume":"107","author":"Majhi","year":"2019","journal-title":"NDT E Int."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"1373","DOI":"10.1109\/TUFFC.2014.006925","article-title":"Compressive Sensing of Full Wave Field Data for Structural Health Monitoring Applications","volume":"62","author":"Perelli","year":"2015","journal-title":"Ultrason. Ferroelectr. Freq. Control. IEEE Trans."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"EL87","DOI":"10.1121\/1.5022699","article-title":"Multichannel Multiple Signal Classification for dispersion curves extraction of ultrasonic guided waves","volume":"143","author":"Zabbal","year":"2018","journal-title":"J. Acoust. Soc. Am."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"1514","DOI":"10.1109\/TUFFC.2016.2592688","article-title":"Sparse SVD Method for High Resolution Extraction of the Dispersion Curves of Ultrasonic Guided Waves","volume":"63","author":"Xu","year":"2016","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"106427","DOI":"10.1016\/j.ultras.2021.106427","article-title":"High-resolution Lamb waves dispersion curves estimation and elastic property inversion","volume":"115","author":"Chen","year":"2021","journal-title":"Ultrasonics"},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"106694","DOI":"10.1016\/j.ymssp.2020.106694","article-title":"Spatio-temporal undersampling: Recovering ultrasonic guided wavefields from incomplete data with compressive sensing","volume":"140","author":"Sabeti","year":"2020","journal-title":"Mech. Syst. Signal Process."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"030012","DOI":"10.1063\/1.4940484","article-title":"Wave mode extraction from multimodal guided wave signal in a plate","volume":"1706","author":"Ratassepp","year":"2016","journal-title":"AIP Conf. Proc."},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"011003","DOI":"10.1117\/1.OE.55.1.011003","article-title":"Guided ultrasonic wave testing of an immersed plate with hidden defects","volume":"55","author":"Bagheri","year":"2016","journal-title":"Opt. Eng."},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"106063","DOI":"10.1016\/j.ultras.2020.106063","article-title":"A baseline-free approach of locating defect based on mode conversion and the reciprocity principle of Lamb waves","volume":"102","author":"Jia","year":"2020","journal-title":"Ultrasonics"},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"851","DOI":"10.1109\/TUFFC.2018.2813278","article-title":"Dynamic Time Warping Temperature Compensation for Guided Wave Structural Health Monitoring","volume":"65","author":"Douglass","year":"2018","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"108153","DOI":"10.1016\/j.ymssp.2021.108153","article-title":"Perception modelling by invariant representation of deep learning for automated structural diagnostic in aircraft maintenance: A study case using DeepSHM","volume":"165","author":"Ewald","year":"2022","journal-title":"Mech. Syst. Signal Process."},{"key":"ref_60","doi-asserted-by":"crossref","first-page":"319","DOI":"10.1016\/j.ultras.2018.08.005","article-title":"Multi-mode reverse time migration damage imaging using ultrasonic guided waves","volume":"94","author":"He","year":"2019","journal-title":"Ultrasonics"},{"key":"ref_61","doi-asserted-by":"crossref","first-page":"946","DOI":"10.1088\/0964-1726\/15\/4\/007","article-title":"A comparison of embedded sensor Lamb wave ultrasonic tomography approaches for material loss detection","volume":"15","author":"Hay","year":"2006","journal-title":"Smart Mater. Struct."},{"key":"ref_62","doi-asserted-by":"crossref","first-page":"233","DOI":"10.1016\/j.compstruct.2018.10.097","article-title":"A weighted sparse reconstruction-based ultrasonic guided wave anomaly imaging method for composite laminates","volume":"209","author":"Xu","year":"2019","journal-title":"Compos. Struct."},{"key":"ref_63","doi-asserted-by":"crossref","first-page":"214301","DOI":"10.7498\/aps.66.214301","article-title":"Reverse time migration Lamb wave imaging based on mode separation","volume":"66","author":"Zhang","year":"2017","journal-title":"Wuli Xuebao Acta Phys. Sin."},{"key":"ref_64","doi-asserted-by":"crossref","first-page":"317","DOI":"10.1016\/j.jsv.2017.04.017","article-title":"Investigation of the reconstruction accuracy of guided wave tomography using full waveform inversion","volume":"400","author":"Rao","year":"2017","journal-title":"J. Sound Vib."},{"key":"ref_65","first-page":"102472","article-title":"Damage quantification in an aluminium-CFRP composite structure using guided wave wavenumber mapping: Comparison of instantaneous and local wavenumber analyses","volume":"122","author":"Lugovtsova","year":"2021","journal-title":"NTD E Int."},{"key":"ref_66","doi-asserted-by":"crossref","unstructured":"Tiwari, K., and Raisutis, R. (2018). Identification and characterization of defects in glass fiber reinforced plastic by refining the guided lamb waves. Materials, 11.","DOI":"10.3390\/ma11071173"},{"key":"ref_67","doi-asserted-by":"crossref","first-page":"89","DOI":"10.1016\/j.ymssp.2017.09.043","article-title":"A guided wave dispersion compensation method based on compressed sensing","volume":"103","author":"Xu","year":"2018","journal-title":"Mech. Syst. Signal Process."},{"key":"ref_68","doi-asserted-by":"crossref","first-page":"35","DOI":"10.1016\/j.ultras.2015.04.009","article-title":"Increased range of ultrasonic guided wave testing of overhead transmission line cables using dispersion compensation","volume":"62","author":"Legg","year":"2015","journal-title":"Ultrasonics"},{"key":"ref_69","doi-asserted-by":"crossref","first-page":"518","DOI":"10.1177\/14759217211005399","article-title":"Stress evaluation in seven-wire strands based on singular value feature of ultrasonic guided waves","volume":"21","author":"Ji","year":"2021","journal-title":"Struct. Health Monit."},{"key":"ref_70","doi-asserted-by":"crossref","unstructured":"Tran, D., Kim, J.W., Tola, K., Kim, W., and Park, S. (2020). Artificial intelligence-based bolt loosening diagnosis using deep learning algorithms for laser ultrasonic wave propagation data. Sensors, 20.","DOI":"10.3390\/s20185329"},{"key":"ref_71","first-page":"86","article-title":"Guided waves damage identification in beams with test pattern dependent series neural network systems","volume":"4","author":"Liew","year":"2008","journal-title":"WSEAS Trans. Signal Process."},{"key":"ref_72","doi-asserted-by":"crossref","unstructured":"Ju, T., and Findikoglu, A. (2022). Large Area Detection of Microstructural Defects with Multi-Mode Ultrasonic Signals. Appl. Sci., 12.","DOI":"10.3390\/app12042082"}],"container-title":["Metals"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2075-4701\/12\/6\/936\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T23:20:47Z","timestamp":1760138447000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2075-4701\/12\/6\/936"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,5,29]]},"references-count":72,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2022,6]]}},"alternative-id":["met12060936"],"URL":"https:\/\/doi.org\/10.3390\/met12060936","relation":{},"ISSN":["2075-4701"],"issn-type":[{"value":"2075-4701","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,5,29]]}}}