Development of a Matlab Code for the Evaluation of Spray Distribution with Water-Sensitive Paper

One of the biggest challenges in agriculture is the reckless use of pesticides and their inappropriate application with consequent waste of product and environmental pollution. The characterization of the spray application is a good preventive technique to regulate the quantity of a certain product, to perform a more efficient application and to restrict the spray drift. The colorimetry, fluorimetry and spectrometry methods are very accurate, but they are costly and time-consuming compared to a Water-Sensitive Paper (WSP) assessment performed by an image analysis software. The software can detect and estimate many drops features using an image often obtained from a scanner. Therefore, the objective of work was to develop a MATLAB code to evaluate the spray distribution over WSPs. After a pre-processing step in which the WSPs were isolated inside the image, the individual drops were identified using the difference between their color (blue) and the remaining dry part of the paper (yellow). Once the surface of every drop was estimated, it was possible to assess the number of the drops per cm2 and the Normal Median Diameter (NMD). The developed MATLAB code was able to detect and analyze droplets deposit on the WSP even with stains of small dimension (<100 μm) through an inexpensive image analysis procedure. The analysis process allowed a description of the spraying activity and showed the potential behind this technique to improve the pesticide spray applications and reduce its environmental dispersion.