Design and first tests of a vision system to be placed on a tele-operated vehicle for monitoring the canopy vigour status in orchards

A vision system able to give a punctual estimation of the canopy vigour (volume, leaves’ chlorophyll content) of an orchard is a key-system for implementing Precision Agriculture. Indeed, such a system, composed by Lidar and NDVI sensors, can give all the information necessary for performing some important field-operations (e.g., pruning, spraying) and, above all, for setting-up automatically and in realtime the relative machines. The first issues when implementing a vision system concern: which type and how many sensors using, how making this system move within an orchard. As proved in some preliminary lab trials, the use of two Lidar sensors, vertically-aligned to give a sort of lateral-linear-stereoscopic vision, manages to avoid the presence of the large “projected shadows” (or “blind spots”) originating when using a single sensor to scan a target. Then, this article presents a compact “mobile lab”, based on an electric tracked bins-carrier, able to move off-road within the orchards and equipped with an ad-hoc developed adjustable tubular frame, designed to carry two Lidar sensors in the individuated configuration, together with other six (NDVI) sensors. This frame allows placing the sensors at different heights to ensure the complete scan of the canopy (even with high fruit trees).