A portable scanning system for evaluation of spray deposit distribution

Preventing over- or under-spray applications on intended targets require a system to rapidly measure spray coverage and provide spray quality feedback information. A portable scanning system was developed that could quickly evaluate spray deposit distribution and coverage area on deposit collectors such as water sensitive paper or Kromekote (R) card. The system is integrated with a handheld business card scanner, deposit collectors, a laptop computer, and a custom-designed software package entitled DepositScan. The software is composed of a set of custom plug-ins that are used by an image-processing program (ImageJ) to produce a number of measurements suitable for describing spray deposit distribution. The program worked with the handheld business card scanner to scan spray deposits on the collectors. After scanning the collectors, individual droplet sizes, their distributions, total droplet number, droplet density, amount of spray deposits, and percentage of spray coverage are displayed on the computer screen and saved in a spreadsheet. Spots smaller than 23.9 mu m are ignored by DepositScan when 2400 dpi resolution was used. Observations of nominal size spots through a stereoscopic microscope verified the accuracy of the system, and demonstrated that because of pixel limitations, the accuracy of any image-processing program using the pixel recognition technique would decrease as the spot sizes decrease. The portable scanning system offers a convenient solution for on-the-spot evaluation of spray quality under various working conditions. (C) 2011 Elsevier B.V. All rights reserved.