Location: Application Technology Research
Project Number: 5082-30500-002-016-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Aug 1, 2026
End Date: Jul 31, 2028
Objective:
1) to develop a sensing fusion system that integrates a laser sensor for tree canopy measurement and a camera-based machine vision system for crop load counting at individual tree level; 2) to integrate and evaluate a precision chemical thinning system by implementing crop counts-based intelligent variable-rate spraying system in apple orchards to reduce the chemical thinner use.
Approach:
The main task of this project is to develop and evaluate a sensor fusion-guided variable-rate control system for the intelligent sprayer. Firstly, a camera-based machine vision system will be developed for detecting and counting crops (flowers and fruitlets) in individual apple trees. Secondly, the machine vision system will be integrated with the laser guided intelligent sprayer system with the fusion of the two sensing systems to calculate the chemical application rate based on the canopy density and crop counts. Finally, the integrated variable-rate control system will be tested in apple orchards with different canopy densities and crop loads to evaluate the performance of the sprayer system in apple crop load management. In the investigations, tree canopies will be divided into sections at vertical direction to align with the spray zones defined by the corresponding nozzles in the intelligent sprayer. For each section, with the information from the laser sensor and machine vision system, the canopy density and crop counts can be obtained. The information will be used for controlling the corresponding nozzles to spray precisely on the canopy while considering the crop counts/density. Field tests will be conducted in an apple orchard during flower or fruitlet stages to reflect the major chemical thinning practices. Prior to the field evaluation on chemical thinning, a series of tests will be conducted to measure the performance of the variable-rate sprayer under the consideration of canopy density and crop load. The integrated system will be used for chemical thinning trials. A side-by-side chemical thinning spray will be conducted using a conventional sprayer, and the chemical usage and thinning performance (fruit number remaining on each tree) will be compared with the integrated variable-rate sprayer. At the end of the project, it is expected that a sensor fusion-guided variable-rate spraying system will be ready for precision chemical thinning of apples and other fruit crops. Furthermore, the developed system will be demonstrated through Penn State extension events, and the results of the project will be published in extension articles and presented in regional grower meetings.