Real time canopy density estimation using ultrasonic envelope signals in the orchard and vineyard

•We develop a system to estimate the crop density using ultrasound sensors.•The signal obtained is highly correlated with the growing season.•Results show that the signal has similar values on both sides of the row.•The system is sensitive enough to detect hailstorm effects on the canopy.

This paper proposes a real-time method, based on an array of ultrasonic sensors, to estimate canopy density in apple orchards and vineyards. This estimation could be used as a reference to adjust the canopy spraying machine parameters with the aim of improving deposition and avoiding drift. Two sets of experiments were carried out, the first one using a single ultrasound sensor in a greenhouse to determine the signal behavior and adjust the algorithms. The second set of experiments were conducted in the orchard and vineyard, under real working conditions. Results show that the signal obtained is highly correlated with the growing season and it has similar values on both sides of the row, with an error of 14.1% in vineyards and 3.8% in apple trees and it is sensitive enough to detect hailstorm effects on the canopy.