The Use of High-Speed Imaging Systems for Applications in Precision Agriculture

High speed imaging (HSI) has been widely used for industrial and military applications such as ballistics, hypervelocity impact, car crash studies, fluid mechanics, and others. In agriculture HSI is mainly used in two domains that both require fast processing: fertilization and spraying.  Fertilization, be it organic or mineral, is essential to agriculture. Over-fertilization can reduce yield and lead to environmental pollution (Mulligan et al., 2006). To prevent these consequences, the fertilization process must be controlled. In Europe and worldwide, mineral fertilization is performed using centrifugal spreaders because they are more cost-efficient than pneumatic spreaders. The process of centrifugal spreading is based on spinning discs which eject large numbers of grains at high speeds (30 to 40 ms-1). To control the spreading process and to predict the distribution pattern on the soil, several characteristics need to be accurately evaluated, i.e., ejection parameters such as velocity and direction, plus granulometry and the angular distribution.  The spray quality generated by agricultural nozzles plays an important role in the application of plant protection products. The ideal nozzle-pressure combination should maximize spray efficiency by increasing deposition and transfer of a lethal dose to the target (Smith et al., 2000) while minimizing residues (Derksen et al., 2008) and off-target losses such as spray drift (Nuyttens et al., 2007a) and user exposure (Nuyttens et al., 2009a). The most important spray characteristics influencing the efficiency of the pesticide application process are the droplet sizes, the droplet velocities and directions, the volume distribution pattern, the spray sheet structure and length, the structure of