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United States Department of Agriculture

Agricultural Research Service

Title: DepositScan, a Scanning Program to Measure Spray Deposition Distributions

Author
item Zhu, Heping

Submitted to: Software and User Manual Public Release
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 30, 2009
Publication Date: April 10, 2009
Repository URL: http://www.ars.usda.gov/mwa/wooster/atru/depositscan
Citation: Zhu, H. 2009. DepositScan, a Scanning Program to Measure Spray Deposition Distributions. Software and User Manual Public Release. Available: http://www.ars.usda.gov/mwa/wooster/atru/depositscan.

Interpretive Summary: Inaccurate application of pesticides on target areas causes serious off-target loss problems including spray drift, resulting in excessive pesticide use, poor food safety, environmental contamination and hazards to workers. A scanning program, DepositScan was developed to quickly evaluate the deposition quality of pesticide spray applications. In operation, the system first scan samples with a handheld business card scanner, and then reports individual droplet sizes, their distributions, total numbers, and percentage of coverage areas. The analysis of a spray deposition sample is completed in less than 30 seconds even under field conditions. The software is available to the public without charge, and can be downloaded from the website (http://www.ars.usda.gov/mwa/wooster/atru/depositscan). To execute the DepositScan software, users need a laptop computer and a handheld business card scanner which can be purchased from any office supply stores or the internet. DepositScan is a tool that farmers can use to optimize equipment settings, techniques, and practices. For extension educators, DepositScan can help train applicators to accurately apply chemicals on targets. For manufacturers, it can accelerate the process for new pesticide formulations and pesticide spraying equipment. It can also help researchers determine factors that influence spray application technology. DepositScan has considerable potential to minimize off-target loss including spray drift, and impact pesticide spray application efficiency and efficacy.

Technical Abstract: DepositScan, a scanning program was developed to quickly measure spray deposit distributions on water sensitive papers or Kromekote cards which are widely used for determinations of pesticide spray deposition quality on target areas. The program is installed in a portable computer and works with a handheld business card scanner to scan spray deposits on target cards. Users can easily carry them to the field to determine spray quality under various working conditions. The program was developed with Eclipse and the Java compiler that produces a set of plugins accepted by the ImageJ application. In operation, DepositScan first requests users to scan samples into 8-bit gray scale images, selects the area for analysis, takes functions of COUNT BLACK AND WHITE PIXELS under ANALYSIS feature in ImageJ to obtain the number of deposits and area of each deposit in the selected area, and then reports individual droplet sizes, their distributions (DV0.1, D V0.5 and D V0.9), total numbers, and percentage of coverage areas. The program has two options for choosing thresholds to adjust image detection quality. The first option is to allow the system to automatically select a detection threshold based on the image contrast. The second option is a user-defined threshold. The scanning resolution used in the program is 600 dpi (or dot per inch), permitting a minimum diameter of droplets that can be identified is 32 µm. The use of DepositScan will improve accuracy of pesticide spray applications.

Last Modified: 10/26/2014
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