Analysis of Spray Droplet and Deposition of Selected Nozzles Using Image Processing Techniques

Abstract

Chemicals are used to improve the quality and productivity of crops. Contrarily, it can cause severe ecological and civic well-being difficulties owing to spray drift. The drift can be reduced by choosing a nozzle that yields the largest droplet dimension, and providing acceptable coverage at the anticipated claim rate and pressure. Droplet dimension distribution depended on nozzle type, which confirmed the potential of these factors for reducing spray drift. As a consequence of spray drift, residents, livestock, terrestrial and aquatic ecosystem may get exposed to toxic elements. On the other hand, aerial spraying has its advantages like greater efficiency, mobility, and more extensive area coverage in less time. An experimental setup was framed to select a nozzle suitable for UAV spraying in coconut palms, and a series of experiments were conducted to identify better deposition and droplet density of spray liquids at different operating pressures. The setup consists of a spray lance with a universal connector to attach the selected nozzle and a stand to hold the nozzle orientation, height, angle, and direction of the spray. The experiments were conducted with combinations of different levels of variables. For all the combinations of variables, samples were drawn to quantify the effect of selected variables on the droplet size generated. The selected nozzle's discharge rate gradually increases with increasing pressure. ImageJ is a Java-based image handling publicly accessible software developed by the US Institutes of Health (NIH) and the DepositScan provides a wide range of attributes of droplets, such as the number of droplets, equivalent diameter, droplet area, etc., measured by using the program. The pre-determined area for determination of the size of droplets was selected, copied, and pasted into a new file, then the image was binarized. The best treatment result was observed in hollow cone nozzle and NTM nozzle, which is suitable for UAV coconut sprayer based on the deposition and droplet density.