{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,4]],"date-time":"2025-11-04T23:06:02Z","timestamp":1762297562051,"version":"build-2065373602"},"reference-count":55,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2010,4,8]],"date-time":"2010-04-08T00:00:00Z","timestamp":1270684800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/3.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Better insights into bird migration can be a tool for assessing the spread of avian borne infections or ecological\/climatologic issues reflected in deviating migration patterns. This paper evaluates whether low budget permanent cameras such as webcams can offer a valuable contribution to the reporting of migratory birds. An experimental design was set up to study the detection capability using objects of different size, color and velocity. The results of the experiment revealed the minimum size, maximum velocity and contrast of the objects required for detection by a standard webcam. Furthermore, a modular processing scheme was proposed to track and follow migratory birds in webcam recordings. Techniques such as motion detection by background subtraction, stereo vision and lens distortion were combined to form the foundation of the bird tracking algorithm. Additional research to integrate webcam networks, however, is needed and future research should enforce the potential of the processing scheme by exploring and testing alternatives of each individual module or processing step.<\/jats:p>","DOI":"10.3390\/s100403480","type":"journal-article","created":{"date-parts":[[2010,4,8]],"date-time":"2010-04-08T10:49:17Z","timestamp":1270723757000},"page":"3480-3503","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":24,"title":["Webcams for Bird Detection and Monitoring: A Demonstration Study"],"prefix":"10.3390","volume":"10","author":[{"given":"Willem W.","family":"Verstraeten","sequence":"first","affiliation":[{"name":"M3-BIORES, Geomatics Engineering, K.U.Leuven, W. de Croylaan 34, BE-3001, Flanders, Belgium"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Bart","family":"Vermeulen","sequence":"additional","affiliation":[{"name":"M3-BIORES, Geomatics Engineering, K.U.Leuven, W. de Croylaan 34, BE-3001, Flanders, Belgium"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jan","family":"Stuckens","sequence":"additional","affiliation":[{"name":"M3-BIORES, Geomatics Engineering, K.U.Leuven, W. de Croylaan 34, BE-3001, Flanders, Belgium"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Stefaan","family":"Lhermitte","sequence":"additional","affiliation":[{"name":"Centro de Estudios Avanzados en Zonas Aridas, Universidad de la Serena Benavente 980, Casilla 599, 172-0170 La Serena, Chile"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Dimitry","family":"Van der Zande","sequence":"additional","affiliation":[{"name":"M3-BIORES, Geomatics Engineering, K.U.Leuven, W. de Croylaan 34, BE-3001, Flanders, Belgium"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Marc","family":"Van Ranst","sequence":"additional","affiliation":[{"name":"Laboratory of Clinical Virology, Rega Institute, K.U.Leuven, Minderbroedersstraat 10, BE-3000 Leuven, Flanders, Belgium"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Pol","family":"Coppin","sequence":"additional","affiliation":[{"name":"M3-BIORES, Geomatics Engineering, K.U.Leuven, W. de Croylaan 34, BE-3001, Flanders, Belgium"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2010,4,8]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"375","DOI":"10.1016\/j.foreco.2006.11.003","article-title":"Using conservation plans and bird monitoring to evaluate ecological effects of management: an example with fuels reduction activities in southwest Oregon","volume":"238","author":"Alexander","year":"2007","journal-title":"Forest Ecol. Manag"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"363","DOI":"10.1016\/j.bihy.2009.06.002","article-title":"Avian influenza, migratory birds and emerging zoonoses: unusual viral RNA, enteropathogens and Cryptosporidium in poultry litter","volume":"2","author":"Rao","year":"2009","journal-title":"Biosci. Hypoth"},{"key":"ref_3","first-page":"1","article-title":"Remote sensing and avian influenza: a review of image processing methods for extracting key variables affecting avian influenza virus survival in water from Earth Observation satellites","volume":"12","author":"Tran","year":"2010","journal-title":"Int. J. Appl. Earth Obs. Geoinf"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Porter, J., Lin, C.-C., Smith, D.E., and Lu, S.-S. (2009). Ecological image databases: from the webcam to the researcher. Ecol. Infor.","DOI":"10.1016\/j.ecoinf.2009.09.001"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"91","DOI":"10.1016\/j.jneumeth.2006.04.005","article-title":"A simple webcam-based approach for the measurement of rodent locomotion and other behavioural parameters","volume":"157","author":"Tort","year":"2006","journal-title":"J. Neurosci. Meth"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"384","DOI":"10.1126\/science.1122438","article-title":"Global patterns of influenza a virus in wild birds","volume":"312","author":"Olsen","year":"2006","journal-title":"Science"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1486","DOI":"10.3201\/eid1210.051577","article-title":"Birds and influenza H5N1 virus movement to and within North America","volume":"12","author":"Rappole","year":"2006","journal-title":"Emerg. Infect. Dis"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"402","DOI":"10.1016\/j.cell.2009.01.029","article-title":"The influenza virus enigma","volume":"136","author":"Salomon","year":"2009","journal-title":"Cell"},{"key":"ref_9","unstructured":"Li, J., Ren, Q., and Jianqin, Y. (2004, January 20\u201325). Study on transmission model of avian influenza. Hefei, China."},{"key":"ref_10","first-page":"1","article-title":"Migratory birds and their possible role in the spread of highly pathogenic Avian Influenza","volume":"357","author":"Algers","year":"2006","journal-title":"EFSA J"},{"key":"ref_11","unstructured":"Paisley, L., Vigre, H., and B\u00f8tner, A. Avian Influenza in wild birds: evaluation of the risk of transmission to swine. Danish institute for infectious animal diseases. Available online: http:\/\/www.dfvf.dk\/Admin\/Public\/DWSDownload.aspx?File=Files%2FFiler%2FHusdyrsygdomme%2FRisikovurdering%2FAvian_Influenza_in_wild_birds.pdf (accessed on 21 April, 2009)."},{"key":"ref_12","unstructured":"Whitworth, D., Newman, S.H., Mundkur, T., and Harris, P. (2007). Wild Birds and Avian Influenza: an Introduction to Applied Field Research and Disease Sampling Techniques, FAO Animal Production and Health Manual, FAO."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"479","DOI":"10.1016\/j.jnca.2006.06.001","article-title":"A video streaming application for urban traffic management","volume":"30","author":"Esteve","year":"2007","journal-title":"J. Netw. Comput. Appl"},{"key":"ref_14","unstructured":"Lincoln, F.C., Peterson, S.R., and Zimmerman, J.L. Circular 16. Northern Prairie Wildlife Research Center Online, 1998. Available online: http:\/\/www.npwrc.usgs.gov\/resource\/birds\/migratio\/index.htm. (accessed on 12 April, 2009)."},{"key":"ref_15","first-page":"361","article-title":"A quantitative study of the nocturnal migration of birds","volume":"3","author":"Lowery","year":"1951","journal-title":"Univ. Kansas Pub. Mus. Nat. Hist"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"92","DOI":"10.2307\/1366764","article-title":"Quantification of nocturnal passerine migration with a portable ceilometers","volume":"77","author":"Able","year":"1975","journal-title":"Condor"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"239","DOI":"10.1111\/j.0908-8857.2001.320306.x","article-title":"Nocturnal autumn bird migration at Falsterbo, South Sweden","volume":"32","author":"Zehnder","year":"2001","journal-title":"J. Avian Biol"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"319","DOI":"10.1111\/j.1557-9263.2006.00060.x","article-title":"Monitoring bird migration with a fixed-beam radar and a thermal-imaging camera","volume":"7","author":"Gauthreaux","year":"2006","journal-title":"J. Field Ornithol"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"293","DOI":"10.1007\/s002650050245","article-title":"Bimodal orientation and the occurrence of temporary reverse bird migration during autumn in south Scandinavia","volume":"38","author":"Karlsson","year":"1996","journal-title":"Behav. Ecol. Sociobiol"},{"key":"ref_20","first-page":"463","article-title":"The use of radio telemetry to measure the feeding behavior of breeding European Golden Plovers","volume":"67","author":"Whittingham","year":"1996","journal-title":"J. Field Ornithol"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"637","DOI":"10.1093\/condor\/107.3.637","article-title":"Nocturnal foraging behavior of wintering Surf Scoters and White-winged Scoters","volume":"107","author":"Lewis","year":"2005","journal-title":"Condor"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"589","DOI":"10.1016\/S0031-9384(00)00409-1","article-title":"A GPS logger and software for analysis of homing in pigeons and small mammals","volume":"71","author":"Steiner","year":"2000","journal-title":"Physiol. Behav"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1460","DOI":"10.1126\/science.1114103","article-title":"Ivory-billed Woodpecker (Campephilus principalis) Persist in Continental North America","volume":"308","author":"Fitzpatrick","year":"2005","journal-title":"Science"},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Berthold, P., Gwinner, E., and Sonnenschein, E. (2003). Avian Migration, Springer-Verlag.","DOI":"10.1007\/978-3-662-05957-9"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"993","DOI":"10.1109\/TPAMI.2003.1217603","article-title":"Advances in computational stereo","volume":"25","author":"Brown","year":"2003","journal-title":"IEEE T. Pattern Ana. Mach. Intell"},{"key":"ref_26","unstructured":"Wakabayashi, Y., and Aoki, M. (, January February,). Traffic flow measurement using stereo slit camera. Vienna, Austria."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"315","DOI":"10.1016\/S0165-7836(03)00080-8","article-title":"The accuracy and precision of underwater measurements of length and maximum body depth of southern bluefin tuna (Thunnus maccoyii) with a stereo-video camera system","volume":"63","author":"Harvey","year":"2003","journal-title":"Fish. Res"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"218","DOI":"10.1016\/j.aquaeng.2006.02.003","article-title":"Extracting fish size using dual underwater cameras","volume":"35","author":"Costa","year":"2006","journal-title":"Aquacult. Eng"},{"key":"ref_29","unstructured":"Tjandranegara, E. (2005). Distance Estimation Algorithm for Stereo Pair Images, School of Electrical and Computer Engineering, Purdue University. Technical report;."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1337","DOI":"10.1109\/TPAMI.2003.1233909","article-title":"Detecting moving objects, ghosts, and shadows in video streams","volume":"25","author":"Cucchiara","year":"2003","journal-title":"IEEE T. Pattern Ana. Mach. Intell"},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Cheung, S.-C., and Kamath, C. (,  2004). Robust techniques for background subtraction in urban traffic video. San Jose, CA, USA.","DOI":"10.1117\/12.526886"},{"key":"ref_32","unstructured":"Piccardi, M. (2004, January 10\u201313). Background subtraction techniques: a review. The Hague, The Netherlands."},{"key":"ref_33","unstructured":"(2007). Matlab 7.5.0 Product Manual, The Math Works, Inc."},{"key":"ref_34","unstructured":"Jacobson, R.E., Ray, S.F., Attridge, G.G., and Axford, R. (2000). The Manual of Photography: Photographic and Digital Imaging, Focal Press."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1016\/S0097-8493(00)00107-2","article-title":"A general method for overlap control in image warping","volume":"25","author":"Tiddeman","year":"2001","journal-title":"Comput. Graph"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"1330","DOI":"10.1109\/34.888718","article-title":"A flexible new technique for camera calibration","volume":"22","author":"Zhang","year":"2000","journal-title":"IEEE T. Pattern Ana. Mach. Intell"},{"key":"ref_37","first-page":"1","article-title":"A generic concept for camera calibration","volume":"2","author":"Sturm","year":"2004","journal-title":"Comput. Vis. Image Underst"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"977","DOI":"10.1016\/j.patrec.2009.04.012","article-title":"Frame difference energy image for gait recognition with incomplete silhouettes","volume":"30","author":"Chen","year":"2009","journal-title":"Pattern Recogn. Lett"},{"key":"ref_39","unstructured":"Haralick, R.M., and Shapiro, L.G. (1992). Computer and Robot Vision, Addison-Wesley."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"143","DOI":"10.1016\/S0262-8856(03)00145-8","article-title":"Tracking multiple vehicles using foreground, background and motion models","volume":"22","author":"Magee","year":"2004","journal-title":"Image Vision Comput"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"747","DOI":"10.1109\/34.868677","article-title":"Learning patterns of activity using real-time tracking","volume":"22","author":"Stauffer","year":"2000","journal-title":"IEEE T. Pattern Ana. Mach. Intell"},{"key":"ref_42","unstructured":"Elgammal, A., Duraiswami, R., and Davis, L.S. (,  2001). Efficient non-parametric adaptive color modeling using fast Gauss transform. Kauai, HI, USA."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"353","DOI":"10.1109\/34.206955","article-title":"A multiple-baseline stereo","volume":"15","author":"Okutomi","year":"1993","journal-title":"IEEE T. Pattern Ana. Mach. Intell"},{"key":"ref_44","doi-asserted-by":"crossref","unstructured":"Koch, R., Pollefeys, M., and Van Gool, L. (,  1998). Multi-viewpoint stereo from uncalibrated videosequences. Freiburg, Germany.","DOI":"10.1007\/BFb0055659"},{"key":"ref_45","unstructured":"Nakabo, Y., Mukai, T., Hattori, Y., Takeuchi, Y., and Ohnishi, N. (2005, January April). Variable baseline stereo tracking vision system using high-speed linear slider. Barcelona, Spain."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"135","DOI":"10.1111\/j.1477-9730.2007.00412.x","article-title":"A review and analyses of plumb-line calibration","volume":"22","author":"Lerma","year":"2007","journal-title":"Photogramm. Rec"},{"key":"ref_47","doi-asserted-by":"crossref","unstructured":"Scaramuzza, D., Martinelli, A., and Siegwart, R. (,  2006). A toolbox for easily calibrating omnidirectional cameras. Beijing, China.","DOI":"10.1109\/IROS.2006.282372"},{"key":"ref_48","unstructured":"Remondino, F., and Fraser, C. (,  2006). Digital Camera Calibration Methods: Considerations and Comparisons. Dresden, Germany."},{"key":"ref_49","unstructured":"Phar, M., and Humphreys, G. (2004). Physically Based Rendering: from Theory to Implementation, Morgan Kaufmann."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"18","DOI":"10.1016\/j.jhydrol.2005.07.007","article-title":"A manifesto for the equifinality thesis","volume":"320","author":"Beven","year":"2006","journal-title":"J. Hydrol"},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"20","DOI":"10.1016\/j.asr.2007.08.021","article-title":"On uncertainties in carbon flux modelling and remotely sensed data assimilation: the Brasschaat pixel case","volume":"41","author":"Verstraeten","year":"2008","journal-title":"Adv. Space Res"},{"key":"ref_52","unstructured":"Barthel, P.H., and Dougalis, P. (2008). New Holland European Bird Guide, New Holland Publishers."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"1133","DOI":"10.1016\/j.anbehav.2008.05.024","article-title":"Sustained bird flights occur at temperatures far beyond expected limits","volume":"76","author":"Schmaljohann","year":"2008","journal-title":"Anim. Behav"},{"key":"ref_54","unstructured":"Infrastructure for Measurements of the European Carbon Cycle: an Integrated Infrastructure Initiative (I3) under the Sixth Framework Programme of the European Commission. Available online: http:\/\/imecc.ipsl.jussieu.fr\/index.html (accessed on 10 March 2010)."},{"key":"ref_55","unstructured":"FLUXNET Available online: http:\/\/www.fluxnet.ornl.gov\/fluxnet\/index.cfm (accessed on 10 March 2010)."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/10\/4\/3480\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T22:02:04Z","timestamp":1760220124000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/10\/4\/3480"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2010,4,8]]},"references-count":55,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2010,4]]}},"alternative-id":["s100403480"],"URL":"https:\/\/doi.org\/10.3390\/s100403480","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2010,4,8]]}}}