{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,6]],"date-time":"2026-10-06T04:06:14Z","timestamp":1791259574109,"version":"4.1.0"},"reference-count":37,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2016,2,6]],"date-time":"2016-02-06T00:00:00Z","timestamp":1454716800000},"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>Accurate spray characterization helps to better understand the pesticide spray application process. The goal of this research was to present the proof of principle of a droplet size and velocity measuring technique for different types of hydraulic spray nozzles using a high speed backlight image acquisition and analysis system. As only part of the drops of an agricultural spray can be in focus at any given moment, an in-focus criterion based on the gray level gradient was proposed to decide whether a given droplet is in focus or not. In a first experiment, differently sized droplets were generated with a piezoelectric generator and studied to establish the relationship between size and in-focus characteristics. In a second experiment, it was demonstrated that droplet sizes and velocities from a real sprayer could be measured reliably in a non-intrusive way using the newly developed image acquisition set-up and image processing. Measured droplet sizes ranged from  24 \u03bcm to 543 \u03bcm, depending on the nozzle type and size. Droplet velocities ranged from around  0.5 m\/s to 12 m\/s. The droplet size and velocity results were compared and related well with the results obtained with a Phase Doppler Particle Analyzer (PDPA).<\/jats:p>","DOI":"10.3390\/s16020218","type":"journal-article","created":{"date-parts":[[2016,2,9]],"date-time":"2016-02-09T13:45:23Z","timestamp":1455025523000},"page":"218","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":53,"title":["Spray Droplet Characterization from a Single Nozzle by High Speed Image Analysis Using an In-Focus Droplet Criterion"],"prefix":"10.3390","volume":"16","author":[{"given":"Sofija","family":"Minov","sequence":"first","affiliation":[{"name":"The Institute for Agricultural and Fisheries Research (ILVO), Technology and Food Science Unit, Agricultural Engineering. Burgemeester Van Gansberghelaan 115, bus 1, Merelbeke 9820, Belgium"},{"name":"Agrosup Dijon, Joint Research Unit Agroecology\u201426 Bd Dr Petitjean, BP 87999, Dijon cedex 21079, France"},{"name":"Department of Biosystems Engineering, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, Ghent 9000, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fr\u00e9d\u00e9ric","family":"Cointault","sequence":"additional","affiliation":[{"name":"Agrosup Dijon, Joint Research Unit Agroecology\u201426 Bd Dr Petitjean, BP 87999, Dijon cedex 21079, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"J\u00fcrgen","family":"Vangeyte","sequence":"additional","affiliation":[{"name":"The Institute for Agricultural and Fisheries Research (ILVO), Technology and Food Science Unit, Agricultural Engineering. Burgemeester Van Gansberghelaan 115, bus 1, Merelbeke 9820, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4034-9269","authenticated-orcid":false,"given":"Jan","family":"Pieters","sequence":"additional","affiliation":[{"name":"Department of Biosystems Engineering, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, Ghent 9000, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4531-0526","authenticated-orcid":false,"given":"David","family":"Nuyttens","sequence":"additional","affiliation":[{"name":"The Institute for Agricultural and Fisheries Research (ILVO), Technology and Food Science Unit, Agricultural Engineering. Burgemeester Van Gansberghelaan 115, bus 1, Merelbeke 9820, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2016,2,6]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1410","DOI":"10.13031\/2013.32451","article-title":"Nozzle spray distribution for pesticide application","volume":"28","author":"Azimi","year":"1985","journal-title":"Trans. ASAE"},{"key":"ref_2","first-page":"1285","article-title":"Influence of plant structure, orifice size and nozzle inclination on spray penetration into peanut canopy","volume":"45","author":"Zhu","year":"2002","journal-title":"Trans. ASAE"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"199","DOI":"10.1002\/ps.2051","article-title":"Effects of nozzle type and spray angle on spray deposition in ivy pot plants","volume":"67","author":"Nuyttens","year":"2011","journal-title":"Pest Manag. 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