title: Spray Droplet Characterization from a Single Nozzle by High Speed Image Analysis Using an In-Focus Droplet Criterion.
abstract: 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 μm to 543 μm, 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).
authors: The Institute for Agricultural and Fisheries Research (ILVO), Technology and Food Science Unit, Agricultural Engineering. Burgemeester Van Gansberghelaan 115, bus 1, Merelbeke 9820, Belgium. sofija.vulgarakis@gmail.com.|Agrosup Dijon, Joint Research Unit Agroecology-26 Bd Dr Petitjean, BP 87999, Dijon cedex 21079, France. sofija.vulgarakis@gmail.com.|Department of Biosystems Engineering, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, Ghent 9000, Belgium. sofija.vulgarakis@gmail.com.
authors: Sofija Vulgarakis
authors: SV
authors: Minov
authors: Agrosup Dijon, Joint Research Unit Agroecology-26 Bd Dr Petitjean, BP 87999, Dijon cedex 21079, France. frederic.cointault@agrosupdijon.fr.
authors: Frédéric
authors: F
authors: Cointault
authors: The Institute for Agricultural and Fisheries Research (ILVO), Technology and Food Science Unit, Agricultural Engineering. Burgemeester Van Gansberghelaan 115, bus 1, Merelbeke 9820, Belgium. jurgen.vangeyte@ilvo.vlaanderen.be.
authors: Jürgen
authors: J
authors: Vangeyte
authors: Department of Biosystems Engineering, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, Ghent 9000, Belgium. jan.pieters@ugent.be.
authors: Jan G
authors: JG
authors: Pieters
authors: The Institute for Agricultural and Fisheries Research (ILVO), Technology and Food Science Unit, Agricultural Engineering. Burgemeester Van Gansberghelaan 115, bus 1, Merelbeke 9820, Belgium. david.nuyttens@ilvo.vlaanderen.be.
authors: David
authors: D
authors: Nuyttens
mesh_terms: D000383:Agriculture; D007091:Image Processing, Computer-Assisted; D010316:Particle Size; D010575:Pesticides / Q000737:chemistry / Q000302:isolation & purification*; D014919:Wind
chemical_list: D010575:Pesticides
keywords: high speed image analysis; piezoelectric droplet generator; spray characterization;   in-focus criterion