{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,17]],"date-time":"2026-03-17T04:56:27Z","timestamp":1773723387754,"version":"3.50.1"},"reference-count":57,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2020,1,7]],"date-time":"2020-01-07T00:00:00Z","timestamp":1578355200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>The breaking wave height is a crucial parameter for coastal studies but direct measurements constitute a difficult task due to logistical and technical constraints. This paper presents two new practical methods for estimating the breaking wave height from digital images collected by shore-based video monitoring systems. Both methods use time-exposure (Timex) images and exploit the cross-shore length (     L  H s      ) of the typical time-averaged signature of breaking wave foam. The first method (    H  s  b , v      ) combines      L  H s       and a series of video-derived parameters with the beach profile elevation to obtain the breaking wave height through an empirical formulation. The second method (    H  s  b , v 24      ) is based on the empirical finding that      L  H s       can be associated with the local water depth at breaking, thus it can be used to estimate the breaking wave height without the requirement of local bathymetry. Both methods were applied and verified against field data collected at the Portuguese Atlantic coast over two days using video acquired by an online-streaming surfcam. Furthermore,     H  s  b , v 24       was applied on coastal images acquired at four additional field sites during distinct hydrodynamic conditions, and the results were compared to a series of different wave sources. Achievements suggest that     H  s  b , v       method represents a good alternative to numerical hydrodynamic modeling when local bathymetry is available. In fact, the differences against modeled breaking wave height, ranging from 1 to 3 m at the case study, returned a root-mean-square-error of 0.2 m. The     H  s  b , v 24       method, when applied on video data collected at five sites, assessed a normalized root-mean-square-error of 18% on average, for dataset of about 900 records and breaking wave height ranging between 0.1 and 3.8 m. These differences demonstrate the potential of     H  s  b , v 24       in estimating breaking wave height merely using Timex images, with the main advantage of not requiring the beach profile. Both methods can be easily implemented as cost-effective tools for hydrodynamic applications in the operational coastal video systems worldwide. In addition, the methods have the potential to be coupled to the numerous other Timex applications for morphodynamic studies.<\/jats:p>","DOI":"10.3390\/rs12020204","type":"journal-article","created":{"date-parts":[[2020,1,8]],"date-time":"2020-01-08T03:59:57Z","timestamp":1578455997000},"page":"204","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":30,"title":["Breaking Wave Height Estimation from Timex Images: Two Methods for Coastal Video Monitoring Systems"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0185-7802","authenticated-orcid":false,"given":"Umberto","family":"Andriolo","sequence":"first","affiliation":[{"name":"INESC Coimbra, Department of Electrical and Computer Engineering, University of Coimbra, Polo 2, 3030-290 Coimbra, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3333-2717","authenticated-orcid":false,"given":"Diogo","family":"Mendes","sequence":"additional","affiliation":[{"name":"CERIS, Instituto Superior T\u00e9cnico, University of Lisbon, Av. Rovisco Pais 1, 1049-001 Lisbon, Portugal"},{"name":"LNEC, National Laboratory for Civil Engineering, Av. do Brasil 101, 1700-066 Lisbon, Portugal"},{"name":"IH, Hydrographic Institute, Rua das Trinas 49, 1200-677 Lisbon, Portugal"}]},{"given":"Rui","family":"Taborda","sequence":"additional","affiliation":[{"name":"IDL, Instituto Dom Luiz, Faculty of Sciences, University of Lisbon, Campo Grande, 1749-016 Lisbon, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2020,1,7]]},"reference":[{"key":"ref_1","unstructured":"Bird, E.C.F. (2014). Coastal Geomorphology: An Introduction, John Wiley & Sons."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"534","DOI":"10.1061\/(ASCE)0733-950X(1992)118:5(534)","article-title":"Wave Runup on Smooth and Rock Slopes of Coastal Structures","volume":"118","author":"Meer","year":"1992","journal-title":"J. Waterway Port Coast. Ocean Eng."},{"key":"ref_3","first-page":"1632","article-title":"Coastal storm risk assessment in Europe: Examples from 9 study sites","volume":"SI56","author":"Ferreira","year":"2009","journal-title":"J. Coast. Res."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Svendsen, I.A. (2006). Introduction to Nearshore Hydrodynamics, World Scientific.","DOI":"10.1142\/5740"},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Battjes, J.A. (1974, January 24\u201328). Surf Similarity. Proceedings of the 14th Asce Coastal Engineering Conference, Copenhagen, Denmark.","DOI":"10.9753\/icce.v14.26"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"257","DOI":"10.1146\/annurev.fl.20.010188.001353","article-title":"Surf-Zone Dynamics","volume":"20","author":"Battjes","year":"1988","journal-title":"Annu. Rev. Fluid Mech."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"7649","DOI":"10.1029\/98JC02622","article-title":"A third-generation wave model for coastal regions 1. Model description and validation","volume":"104","author":"Booij","year":"1999","journal-title":"J. Geophys. Res. Ocean."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"992","DOI":"10.1016\/j.coastaleng.2011.05.015","article-title":"SWASH: An operational public domain code for simulating wave fields and rapidly varied flows in coastal waters","volume":"58","author":"Zijlema","year":"2011","journal-title":"Coast. Eng."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1028","DOI":"10.2112\/05-0566.1","article-title":"Predictive Formulas for Breaker Depth Index and Breaker Type","volume":"234","author":"Camenen","year":"2007","journal-title":"J. Coast. Res."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1350002","DOI":"10.1142\/S0578563413500022","article-title":"Breaking Waves: Review of Characteristic Relationships","volume":"55","author":"Robertson","year":"2013","journal-title":"Coast. Eng. J."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"445","DOI":"10.1016\/j.coastaleng.2006.11.007","article-title":"Near-shore swell estimation from a global wind-wave model: Spectral process, linear, and artificial neural network models","volume":"54","author":"Browne","year":"2007","journal-title":"Coast. Eng."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"3074","DOI":"10.1002\/grl.50584","article-title":"Field measurements and scaling of ocean surface wave-breaking statistics","volume":"40","author":"Sutherland","year":"2013","journal-title":"Geophys. Res. Lett."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"27","DOI":"10.1016\/j.coastaleng.2017.01.006","article-title":"The influence of swash-based reflection on surf zone hydrodynamics: a wave-by-wave approach","volume":"122","author":"Martins","year":"2017","journal-title":"Coast. Eng."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Andriolo, U., S\u00e1nchez-Garc\u00eda, E., and Taborda, R. (2019). Operational use of surfcam online streaming images for coastal morphodynamic studies. Remote Sens., 11.","DOI":"10.3390\/rs11010078"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"551","DOI":"10.1007\/s11852-013-0292-x","article-title":"Shoreline rotation and response to nourishment of a gravel embayed beach using a low-cost video monitoring technique: San Michele-Sassi Neri, Central Italy","volume":"18","author":"Harley","year":"2014","journal-title":"J. Coast. Conserv."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"477","DOI":"10.1016\/j.coastaleng.2007.01.003","article-title":"The history and technical capabilities of Argus","volume":"54","author":"Holman","year":"2007","journal-title":"Coast. Eng."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"42","DOI":"10.1016\/j.coastaleng.2011.12.004","article-title":"A new breaking wave height direct estimator from video imagery","volume":"61","author":"Almar","year":"2012","journal-title":"Coast. Eng."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Gal, Y., Browne, M., and Lane, C. (2011, January 6\u20138). Automatic estimation of nearshore wave height from video timestacks. Proceedings of the 2011 International Conference on Digital Image Computing: Techniques and Applications (DICTA 2011), Noosa, Australia.","DOI":"10.1109\/DICTA.2011.68"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Andriolo, U. (2019). Nearshore Wave Transformation Domains from Video Imagery. J. Mar. Sci. Eng., 7.","DOI":"10.3390\/jmse7060186"},{"key":"ref_20","first-page":"671","article-title":"Automated Detection of Breaking Wave Height Using an Optical Technique","volume":"28","author":"Shand","year":"2012","journal-title":"J. Coast. Res."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"39","DOI":"10.2495\/CP090041","article-title":"Use of video imagery to test model predictions of surf heights","volume":"126","author":"Huntley","year":"2009","journal-title":"WIT Trans. Ecol. Environ."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"201","DOI":"10.1016\/j.geomorph.2010.11.004","article-title":"Dynamics of a nearshore bar system in the northern Adriatic: A video-based morphological classification","volume":"126","author":"Armaroli","year":"2011","journal-title":"Geomorphology"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"209","DOI":"10.1016\/j.margeo.2006.10.029","article-title":"Observations of rip spacing, persistence and mobility at a long, straight coastline","volume":"236","author":"Turner","year":"2007","journal-title":"Mar. Geol."},{"key":"ref_24","first-page":"218","article-title":"Sea level at cascais tide gauge: Data, analysis and results","volume":"56","author":"Antunes","year":"2009","journal-title":"J. Coast. Res."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"248","DOI":"10.1016\/j.cageo.2012.07.013","article-title":"COSMOS: A lightweight coastal video monitoring system","volume":"49","author":"Taborda","year":"2012","journal-title":"Comput. Geosci."},{"key":"ref_26","unstructured":"Holthuijsen, L.H. (2015). Waves in Oceanic and Coastal Waters, Cambridge University Press."},{"key":"ref_27","unstructured":"Battjes, J.A., and Janssen, J.P.F.M. (September, January 27). Energy Loss and Set-Up Due To Breaking of Random Waves. Proceedings of the 16th International Conference on Coastal Engineering, Hamburg, Germany."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"995","DOI":"10.1029\/JC094iC01p00995","article-title":"Quantification of sand bar morphology: a video technique based on wave dissipation","volume":"94","author":"Lippmann","year":"1989","journal-title":"J. Geophys. Res."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"93","DOI":"10.1016\/j.coastaleng.2007.09.010","article-title":"Remote sensing of breaking wave phase speeds with application to non-linear depth inversions","volume":"55","author":"Haller","year":"2008","journal-title":"Coast. Eng."},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Haller, M.C., and Catal\u00e1n, P.A. (2009). Remote sensing of wave roller lengths in the laboratory. J. Geophys. Res. Ocean., 114.","DOI":"10.1029\/2008JC005185"},{"key":"ref_31","unstructured":"Kamphuis, J.W. (2012). Introduction to Coastal Engineering and Management, World Scientific."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"351","DOI":"10.1080\/14786449408620643","article-title":"On the highest wave of permanent type","volume":"5","author":"McCowan","year":"1894","journal-title":"Philos. Mag. J. Sci."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"41","DOI":"10.9753\/icce.v34.waves.41","article-title":"Remote measurement and prediction of breaking wave parameters","volume":"1","author":"Robertson","year":"2014","journal-title":"Coast. Eng. Proc."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"30","DOI":"10.1016\/j.ocemod.2014.12.011","article-title":"Scaling depth-induced wave-breaking in two-dimensional spectral wave models","volume":"87","author":"Salmon","year":"2015","journal-title":"Ocean Model."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"71","DOI":"10.1142\/S0578563410002129","article-title":"Reanalysis of regular and random breaking wave statistics","volume":"52","author":"Goda","year":"2010","journal-title":"Coast. Eng. J."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"185","DOI":"10.1016\/0378-3839(91)90002-X","article-title":"Incipient wave breaking","volume":"15","author":"Kamphuis","year":"1991","journal-title":"Coast. Eng."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"2991","DOI":"10.1029\/JC080i021p02991","article-title":"The theory of wave propagation in water of gradually varying depth and the prediction of breaker type and height","volume":"80","author":"Gaughan","year":"1975","journal-title":"J. Geophys. Res."},{"key":"ref_38","first-page":"1","article-title":"Operational forecast framework applied to extreme sea levels at regional and local scales","volume":"10","author":"Fortunato","year":"2017","journal-title":"J. Oper. Oceanogr."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"255","DOI":"10.1016\/j.isprsjprs.2017.03.023","article-title":"C-Pro: A coastal projector monitoring system using terrestrial photogrammetry with a geometric horizon constraint","volume":"128","year":"2017","journal-title":"ISPRS J. Photogramm. Remote Sens."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"144","DOI":"10.1016\/j.margeo.2018.12.003","article-title":"A synthetic review of remote sensing applications to detect nearshore bars","volume":"408","author":"Ellis","year":"2019","journal-title":"Mar. Geol."},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Splinter, K.D., Harley, M.D., and Turner, I.L. (2018). Remote sensing is changing our view of the coast: Insights from 40 years of monitoring at Narrabeen-Collaroy, Australias. Remote Sens., 10.","DOI":"10.3390\/rs10111744"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"3106","DOI":"10.1002\/2016JC012233","article-title":"Remote sensing of the correlation between breakpoint oscillations and infragravity waves in the surf and swash zone","volume":"122","author":"Moura","year":"2017","journal-title":"J. Geophys. Res. Ocean."},{"key":"ref_43","first-page":"150901234203000","article-title":"Prediction of Incipient Breaking Wave Heights Using Artificial Neural Networks and Empirical Relationships","volume":"31","author":"Robertson","year":"2015","journal-title":"Coast. Eng. J."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"2595","DOI":"10.1002\/jgrc.20199","article-title":"CBathy: A robust algorithm for estimating nearshore bathymetry","volume":"118","author":"Holman","year":"2013","journal-title":"J. Geophys. Res. Ocean."},{"key":"ref_45","first-page":"3","article-title":"Nearshore bathymetric inversion from video using a fully non-linear Boussinesq wave model","volume":"64","author":"Almar","year":"2011","journal-title":"J. Coast. Res."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"1521","DOI":"10.1007\/s10236-011-0440-5","article-title":"Performance of intertidal topography video monitoring of a meso-tidal reflective beach in South Portugal","volume":"61","author":"Vousdoukas","year":"2011","journal-title":"Ocean Dyn."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"232","DOI":"10.1016\/j.coastaleng.2018.07.009","article-title":"Coupling terrestrial LiDAR and video imagery to perform 3D intertidal beach topography","volume":"140","author":"Andriolo","year":"2018","journal-title":"Coast. Eng."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"1016","DOI":"10.1016\/j.coastaleng.2008.04.011","article-title":"Beach Wizard: Nearshore bathymetry estimation through assimilation of model computations and remote observations","volume":"55","author":"Plant","year":"2008","journal-title":"Coast. Eng."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"9499","DOI":"10.1029\/JC087iC12p09499","article-title":"Energy saturation and phase speeds measured on the natural beach","volume":"87","author":"Thornton","year":"1982","journal-title":"J. Geophys. Res."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"7965431","DOI":"10.1155\/2016\/7965431","article-title":"Monitoring individual wave characteristics in the inner surf with a 2-dimensional laser scanner (LiDAR)","volume":"2016","author":"Martins","year":"2016","journal-title":"J. Sens."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"37","DOI":"10.1016\/j.coastaleng.2017.07.007","article-title":"High-resolution monitoring of wave transformation in the surf zone using a LiDAR scanner array","volume":"128","author":"Martins","year":"2017","journal-title":"Coast. Eng."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"175","DOI":"10.1016\/j.coastaleng.2019.04.003","article-title":"Shoreline change mapping using crowd-sourced smartphone images","volume":"150","author":"Harley","year":"2019","journal-title":"Coast. Eng."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"2017","DOI":"10.1109\/TGRS.2016.2635120","article-title":"Surf Zone Characterization Using a Small Quadcopter: Technical Issues and Procedures","volume":"55","author":"Holman","year":"2017","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"5059","DOI":"10.1080\/01431161.2018.1446568","article-title":"Accuracy and effectiveness of low cost UASs and open source photogrammetric software for foredunes mapping","volume":"39","author":"Duarte","year":"2018","journal-title":"Int. J. Remote Sens."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"103527","DOI":"10.1016\/j.coastaleng.2019.103527","article-title":"On the operational use of UAVs for video-derived bathymetry","volume":"152","author":"Bergsma","year":"2019","journal-title":"Coast. Eng."},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"1433","DOI":"10.2112\/SI65-242.1","article-title":"Capitalizing on the surfcam phenomenon: a pilot study in regional-scale shoreline and inshore wave monitoring utilizing existing camera infrastructure","volume":"165","author":"Mole","year":"2013","journal-title":"J. Coast. Res."},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"542","DOI":"10.2112\/JCOASTRES-D-14-00090.1","article-title":"Evaluation of Opportunistic Shoreline Monitoring Capability Utilizing Existing \u201cSurfcam\u201d Infrastructure","volume":"319","author":"Bracs","year":"2016","journal-title":"J. Coast. Res."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/12\/2\/204\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,13]],"date-time":"2025-10-13T13:28:59Z","timestamp":1760362139000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/12\/2\/204"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,1,7]]},"references-count":57,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2020,1]]}},"alternative-id":["rs12020204"],"URL":"https:\/\/doi.org\/10.3390\/rs12020204","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,1,7]]}}}