{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T04:08:06Z","timestamp":1760242086318,"version":"build-2065373602"},"reference-count":58,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2018,12,13]],"date-time":"2018-12-13T00:00:00Z","timestamp":1544659200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Canopy characterization has become important when trying to optimize any kind of agricultural operation in high-growing crops, such as olive. Many sensors and techniques have reported satisfactory results in these approaches and in this work a 2D laser scanner was explored for measuring canopy trees in real-time conditions. The sensor was tested in both laboratory and field conditions to check its accuracy, its cone width, and its ability to characterize olive canopies in situ. The sensor was mounted on a mast and tested in laboratory conditions to check: (i) its accuracy at different measurement distances; (ii) its measurement cone width with different reflectivity targets; and (iii) the influence of the target\u2019s density on its accuracy. The field tests involved both isolated and hedgerow orchards, in which the measurements were taken manually and with the sensor. The canopy volume was estimated with a methodology consisting of revolving or extruding the canopy contour. The sensor showed high accuracy in the laboratory test, except for the measurements performed at 1.0 m distance, with 60 mm error (6%). Otherwise, error remained below 20 mm (1% relative error). The cone width depended on the target reflectivity. The accuracy decreased with the target density.<\/jats:p>","DOI":"10.3390\/s18124406","type":"journal-article","created":{"date-parts":[[2018,12,14]],"date-time":"2018-12-14T03:58:17Z","timestamp":1544759897000},"page":"4406","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":9,"title":["Assessment of the Accuracy of a Multi-Beam LED Scanner Sensor for Measuring Olive Canopies"],"prefix":"10.3390","volume":"18","author":[{"given":"Rafael R.","family":"Sola-Guirado","sequence":"first","affiliation":[{"name":"Rural Engineering Department, University of Cordoba. Ed. Leonardo da Vinci, Campus Rabanales, Ctra. Nacional IV, km 396, 14014 C\u00f3rdoba, Spain"}]},{"given":"Sergio","family":"Bayano-Tejero","sequence":"additional","affiliation":[{"name":"Rural Engineering Department, University of Cordoba. Ed. Leonardo da Vinci, Campus Rabanales, Ctra. Nacional IV, km 396, 14014 C\u00f3rdoba, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1436-465X","authenticated-orcid":false,"given":"Antonio","family":"Rodr\u00edguez-Lizana","sequence":"additional","affiliation":[{"name":"Aerospace Engineering and Fluid Mechanics Department, University of Seville, Ctra. de Utrera km 1, 41013 Sevilla, Spain"}]},{"given":"Jes\u00fas A.","family":"Gil-Ribes","sequence":"additional","affiliation":[{"name":"Rural Engineering Department, University of Cordoba. Ed. Leonardo da Vinci, Campus Rabanales, Ctra. Nacional IV, km 396, 14014 C\u00f3rdoba, Spain"}]},{"given":"Antonio","family":"Miranda-Fuentes","sequence":"additional","affiliation":[{"name":"Rural Engineering Department, University of Cordoba. Ed. Leonardo da Vinci, Campus Rabanales, Ctra. Nacional IV, km 396, 14014 C\u00f3rdoba, Spain"}]}],"member":"1968","published-online":{"date-parts":[[2018,12,13]]},"reference":[{"key":"ref_1","first-page":"1","article-title":"A System for Adjusting the Spray Application to the Target Characteristics","volume":"X","author":"Balsari","year":"2008","journal-title":"Agric. Eng. Int. CIGR J."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"13","DOI":"10.1016\/S0261-2194(00)00046-6","article-title":"Spray deposits and losses in different sized apple trees from an axial fan orchard sprayer: 1. Effects of spray liquid flow rate","volume":"20","author":"Cross","year":"2001","journal-title":"Crop Prot."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"200","DOI":"10.1016\/j.cropro.2014.10.016","article-title":"Spray deposition profiles in pome fruit trees: Effects of sprayer design, training system and tree canopy characteristics","volume":"67","author":"Duga","year":"2015","journal-title":"Crop Prot."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"7598","DOI":"10.3390\/s120607598","article-title":"Analysis of the air flow generated by an air-assisted sprayer equipped with two axial fans using a 3D sonic anemometer","volume":"12","author":"Vidal","year":"2012","journal-title":"Sensors"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"691","DOI":"10.3390\/s140100691","article-title":"Advanced Technologies for the Improvement of Spray Application Techniques in Spanish Viticulture: An Overview","volume":"14","author":"Gil","year":"2014","journal-title":"Sensors"},{"key":"ref_6","first-page":"31","article-title":"Difficulties to apply ISO 22866 requirements for drift measurements. A particular case of traditional olive tree plantations","volume":"132","author":"Llorens","year":"2016","journal-title":"Asp. Appl. Biol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"250","DOI":"10.1016\/j.scitotenv.2015.08.012","article-title":"Influence of liquid-volume and airflow rates on spray application quality and homogeneity in super-intensive olive tree canopies","volume":"537","author":"Gil","year":"2015","journal-title":"Sci. Total Environ."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"124","DOI":"10.1016\/j.compag.2011.09.007","article-title":"A review of methods and applications of the geometric characterization of tree crops in agricultural activities","volume":"81","author":"Rosell","year":"2012","journal-title":"Comput. Electron. Agric."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Llop, J., Gil, E., Llorens, J., Miranda-Fuentes, A., and Gallart, M. (2016). Testing the suitability of a terrestrial 2D LiDAR scanner for canopy characterization of greenhouse tomato crops. Sensors, 16.","DOI":"10.3390\/s16091435"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"365","DOI":"10.1006\/jaer.1996.0039","article-title":"Analysis of and Experimental Measurements made on a Moving Air-Assisted Sprayer with Two-Dimensional Air-Jets Penetrating a Uniform Crop Canopy","volume":"63","author":"Walklate","year":"1996","journal-title":"J. Agric. Eng. Res."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"186","DOI":"10.1016\/j.biosystemseng.2013.12.007","article-title":"Traditional olive tree response to oil olive harvesting technologies","volume":"118","year":"2014","journal-title":"Biosyst. Eng."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"3671","DOI":"10.3390\/s150203671","article-title":"Towards an optimized method of olive tree crown volume measurement","volume":"15","author":"Llorens","year":"2015","journal-title":"Sensors"},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Landers, A.J. (2010). Developments towards an automatic precision sprayer for fruit crop canopies. 2010 Pittsburgh, Pennsylvania, June 20\u2013June 23, 2010, American Society of Agricultural and Biological Engineers.","DOI":"10.13031\/2013.29778"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"303","DOI":"10.13031\/2013.41240","article-title":"Development of a Variable-Rate Sprayer for Nursery Liner Applications","volume":"55","author":"Jeon","year":"2012","journal-title":"Trans. ASABE"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"128","DOI":"10.1016\/j.biosystemseng.2008.10.009","article-title":"A tractor-mounted scanning LIDAR for the non-destructive measurement of vegetative volume and surface area of tree-row plantations: A comparison with conventional destructive measurements","volume":"102","author":"Sanz","year":"2009","journal-title":"Biosyst. Eng."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"271","DOI":"10.1016\/S0021-8634(89)80024-1","article-title":"Sprayer control by sensing orchard crop characteristics: Orchard architecture and spray liquid savings","volume":"43","author":"Giles","year":"1989","journal-title":"J. Agric. Eng. Res."},{"key":"ref_17","first-page":"564","article-title":"Optimization of agrochemical application in olive groves based on positioning sensor","volume":"12","author":"Gil","year":"2010","journal-title":"Precis. Agric."},{"key":"ref_18","first-page":"1263","article-title":"Spray Deposition inside Tree Canopies from a Newly Developed Variable-Rate Air-Assisted Sprayer","volume":"56","author":"Chen","year":"2013","journal-title":"Trans. ASABE"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"122","DOI":"10.1016\/j.compag.2013.02.004","article-title":"Variable rate sprayer. Part 1\u2014Orchard prototype: Design, implementation and validation","volume":"95","author":"Planas","year":"2013","journal-title":"Comput. Electron. Agric."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"136","DOI":"10.1016\/j.compag.2013.02.010","article-title":"Variable rate sprayer. Part 2\u2014Vineyard prototype: Design, implementation, and validation","volume":"95","author":"Gil","year":"2013","journal-title":"Comput. Electron. Agric."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"139","DOI":"10.1016\/j.compag.2017.10.011","article-title":"Automated system for real time tree canopy contact with canopy shakers","volume":"143","year":"2017","journal-title":"Comput. Electron. Agric."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"2902","DOI":"10.3390\/s150202902","article-title":"Testing Accuracy of Long-Range Ultrasonic Sensors for Olive Tree Canopy Measurements","volume":"15","author":"Llorens","year":"2015","journal-title":"Sensors"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"7","DOI":"10.1016\/j.biosystemseng.2013.02.003","article-title":"LiDAR simulation in modelled orchards to optimise the use of terrestrial laser scanners and derived vegetative measures","volume":"115","author":"Sanz","year":"2013","journal-title":"Biosyst. Eng."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"29","DOI":"10.1016\/0168-1923(94)02175-J","article-title":"Non-destructive measurement of leaf area in olive (Olea europaea L.) trees using a gap inversion method","volume":"73","author":"Villalobos","year":"1995","journal-title":"Agric. For. Meteorol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"467","DOI":"10.1007\/s11119-005-4243-x","article-title":"Performance of an ultrasonic tree volume measurement system in commercial citrus groves","volume":"6","author":"Zaman","year":"2005","journal-title":"Precis. Agric."},{"key":"ref_26","first-page":"285","article-title":"Relationship between orchard tree crop structure and performance characteristics of an axial fan sprayer","volume":"57","author":"Cross","year":"2000","journal-title":"Asp. Appl. Biol."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"258","DOI":"10.1016\/j.eja.2008.12.004","article-title":"The effects of regulated and continuous deficit irrigation on the water use, growth and yield of olive trees","volume":"30","author":"Iniesta","year":"2009","journal-title":"Eur. J. Agron."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Sola-Guirado, R.R., Castillo-Ruiz, F.J., Jim\u00e9nez-Jim\u00e9nez, F., Blanco-Roldan, G.L., Castro-Garcia, S., and Gil-Ribes, J.A. (2017). Olive actual \u201con year\u201d yield forecast tool based on the tree canopy geometry using UAS imagery. Sensors, 17.","DOI":"10.3390\/s17081743"},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Yadav, S., Rizvi, I., and Kadam, S. (2015, January 4\u20136). Urban tree canopy detection using object-based image analysis for very high resolution satellite images: A literature review. Proceedings of the 2015 International Conference on Technologies for Sustainable Development (ICTSD), Mumbai, India.","DOI":"10.1109\/ICTSD.2015.7095889"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"83","DOI":"10.1016\/j.compag.2016.09.014","article-title":"Mapping almond orchard canopy volume, flowers, fruit and yield using lidar and vision sensors","volume":"130","author":"Underwood","year":"2016","journal-title":"Comput. Electron. Agric."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"357","DOI":"10.1016\/j.biosystemseng.2004.12.008","article-title":"A Stereovision-based crop row detection method for tractor-automated guidance","volume":"90","author":"Kise","year":"2005","journal-title":"Biosyst. Eng."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"251","DOI":"10.1016\/j.biosystemseng.2004.11.013","article-title":"Creation of Three-dimensional Crop Maps based on Aerial Stereoimages","volume":"90","author":"Zhang","year":"2005","journal-title":"Biosyst. Eng."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"6237","DOI":"10.3390\/s110606237","article-title":"Georeferenced LiDAR 3D Vine Plantation Map Generation","volume":"11","author":"Llorens","year":"2011","journal-title":"Sensors"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"367","DOI":"10.13031\/2013.8587","article-title":"Investigation of laser and ultrasonic ranging sensors for measurements of citrus canopy volume","volume":"18","author":"Tumbo","year":"2002","journal-title":"Appl. Eng. Agric."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"1287","DOI":"10.1016\/j.cropro.2006.11.003","article-title":"Variable rate application of plant protection products in vineyard using ultrasonic sensors","volume":"26","author":"Gil","year":"2007","journal-title":"Crop Prot."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"1595","DOI":"10.13031\/2013.19174","article-title":"Development of a laser scanner for measuring tree canopy characteristics: Phase 2. Foliage density measurement","volume":"48","author":"Wei","year":"2005","journal-title":"Trans. ASABE"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"1423","DOI":"10.13031\/2013.29122","article-title":"Regulating airflow of orchard airblast sprayer based on tree foliage density","volume":"52","author":"Pai","year":"2009","journal-title":"Trans. ASABE"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"108","DOI":"10.1016\/j.compag.2015.05.014","article-title":"Real time canopy density estimation using ultrasonic envelope signals in the orchard and vineyard","volume":"115","author":"Palleja","year":"2015","journal-title":"Comput. Electron. Agric."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"2459","DOI":"10.3390\/s110302459","article-title":"Performance of an Ultrasonic Ranging Sensor in Apple Tree Canopies","volume":"11","author":"Planas","year":"2011","journal-title":"Sensors"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"39","DOI":"10.13031\/2013.20186","article-title":"Estimation of citrus fruit yield using ultrasonically-sensed tree size","volume":"22","author":"Zaman","year":"2006","journal-title":"Appl. Eng. Agric."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"15500","DOI":"10.3390\/s121115500","article-title":"Programmable ultrasonic sensing system for targeted spraying in orchards","volume":"12","author":"Stajnko","year":"2012","journal-title":"Sensors"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"783","DOI":"10.1046\/j.1365-3040.2000.00600.x","article-title":"Ground monitoring the light-shadow windows of a tree canopy to yield canopy light interception and morphological traits","volume":"23","author":"Giuliani","year":"2000","journal-title":"Plant Cell Environ."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.compag.2016.03.017","article-title":"Evaluation of a LiDAR-based 3D-stereoscopic vision system for crop-monitoring applications","volume":"124","author":"Bietresato","year":"2016","journal-title":"Comput. Electron. Agric."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"153","DOI":"10.1016\/j.agrformet.2012.11.013","article-title":"Relationship between tree row LIDAR-volume and leaf area density for fruit orchards and vineyards obtained with a LIDAR 3D Dynamic Measurement System","volume":"171","author":"Sanz","year":"2013","journal-title":"Agric. For. Meteorol."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"5769","DOI":"10.3390\/s110605769","article-title":"Innovative LIDAR 3D Dynamic Measurement System to Estimate Fruit-Tree Leaf Area","volume":"11","author":"Camp","year":"2011","journal-title":"Sensors"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"204","DOI":"10.1016\/j.agrformet.2010.10.005","article-title":"Field characterization of olive (Olea europaea L.) tree crown architecture using terrestrial laser scanning data","volume":"151","author":"Moorthy","year":"2011","journal-title":"Agric. For. Meteorol."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"1505","DOI":"10.1016\/j.agrformet.2009.04.008","article-title":"Obtaining the three-dimensional structure of tree orchards from remote 2D terrestrial LIDAR scanning","volume":"149","author":"Rosell","year":"2009","journal-title":"Agric. For. Meteorol."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"2177","DOI":"10.3390\/s110202177","article-title":"Ultrasonic and LIDAR Sensors for Electronic Canopy Characterization in Vineyards: Advances to Improve Pesticide Application Methods","volume":"11","author":"Llorens","year":"2011","journal-title":"Sensors"},{"key":"ref_49","first-page":"159","article-title":"Los productos qu\u00edmicos en la olivicultura actual","volume":"102","author":"Campillo","year":"1998","journal-title":"Phytoma Espa\u00f1a"},{"key":"ref_50","unstructured":"Parliament, E. (2009). European Directive 2009\/128\/EC for the Sustainable Use of Pesticides, European Parliamentary Research Service."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"1624","DOI":"10.13031\/2013.30614","article-title":"Control of orchard spraying based on electronic sensing of target characteristics","volume":"30","author":"Giles","year":"1987","journal-title":"Trans. ASAE"},{"key":"ref_52","first-page":"1","article-title":"Drift, drift reducing sprayers and sprayer testing","volume":"57","author":"Ganzelmeier","year":"2000","journal-title":"Asp. Appl. Biol."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"545","DOI":"10.1016\/j.cropro.2007.08.012","article-title":"Targeted spray technology to reduce pesticide in runoff from dormant orchards","volume":"27","author":"Brown","year":"2008","journal-title":"Crop Prot."},{"key":"ref_54","unstructured":"Miranda-Fuentes, A., Cuenca, A., Godoy-Nieto, A., Gonz\u00e1lez-S\u00e1nchez, E.J., de Fuentes, P.M., Blanco-Rold\u00e1n, G.L., and Gil-Ribes, J.A. (2017, January 10\u201312). Field testing and monitoring of newly designed airblast sprayers in traditional olive orchards. Proceedings of the 14th Workshop on Spray Application Techniques in Fruit Growing, Hasselt, Belgium."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"83","DOI":"10.1016\/j.cropro.2016.12.016","article-title":"Comparison between standard and drift reducing nozzles for pesticide application in citrus: Part II. Effects on canopy spray distribution, control efficacy of Aonidiella aurantii (Maskell), beneficial parasitoids and pesticide residues on fruit","volume":"94","author":"Torrent","year":"2017","journal-title":"Crop Prot."},{"key":"ref_56","doi-asserted-by":"crossref","unstructured":"Doruchowski, G., Balsari, P., and Van De Zande, J. (2008, January 6). Development of a crop adapted spray application system for sustainable plant protection in fruit growing. Proceedings of the International Symposium on Application of Precision Agriculture for Fruits and Vegetables, Orlando, FL, USA.","DOI":"10.17660\/ActaHortic.2009.824.29"},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"239","DOI":"10.1016\/j.cropro.2009.12.022","article-title":"Variable rate dosing in precision viticulture: Use of electronic devices to improve application efficiency","volume":"29","author":"Llorens","year":"2010","journal-title":"Crop Prot."},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"44","DOI":"10.1016\/j.cropro.2016.12.012","article-title":"Improving plant protection product applications in traditional and intensive olive orchards through the development of new prototype air-assisted sprayers","volume":"94","author":"Cuenca","year":"2017","journal-title":"Crop Prot."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/18\/12\/4406\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T15:33:42Z","timestamp":1760196822000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/18\/12\/4406"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,12,13]]},"references-count":58,"journal-issue":{"issue":"12","published-online":{"date-parts":[[2018,12]]}},"alternative-id":["s18124406"],"URL":"https:\/\/doi.org\/10.3390\/s18124406","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2018,12,13]]}}}