An important area in precision agriculture is related to the efficient use of chemicals applied onto fields. Efforts have been made to diminish their use, aiming at cost reduction and fewer chemical residues in the final agricultural products. The use of unmanned aerial vehicles (UAVs) presents itself as an attractive and cheap alternative for spraying pesticides and fertilizers compared to conventional mass spraying performed by ordinary manned aircraft. Besides being cheaper than manned aircraft, small UAVs are capable of performing fine-grained instead of the mass spraying. Observing this improved method, this paper reports the design of an embedded real-time UAV spraying control system supported by onboard image processing. The proposal uses a normalized difference vegetation index (NDVI) algorithm to detect the exact locations in which the chemicals are needed. Using this information, the automated spraying control system performs punctual applications while the UAV navigates over the crops. The system architecture is designed to run on low-cost hardware, which demands an efficient NDVI algorithm. The experiments were conducted using Raspberry Pi 3 as the embedded hardware. First, experiments in a laboratory were conducted in which the algorithm was proved to be correct and efficient. Then, field tests in real conditions were conducted for validation purposes. These validation tests were performed in an agronomic research station with the Raspberry hardware integrated into a UAV flying over a field of crops. The average CPU usage was about 20% while memory consumption was about 70 MB for high definition images, with 4% CPU usage and 20.3 MB RAM being observed for low-resolution images. The average current measured to execute the proposed algorithm was 0.11 A. The obtained results prove that the proposed solution is efficient in terms of processing and energy consumption when used in embedded hardware and provides measurements which are coherent with the commercial GreenSeeker equipment.
Unmanned aerial vehicles (UAVs) have been widely used in many applications due to, among other features, their versatility, reduced operation cost, and reduced size. These applications increasingly require that features related to autonomous navigation be employed, such as mapping. However, the reduced capacity of resources such as battery life and hardware (memory and processing capacity) can hinder the development of these applications in UAVs. Thus, the collaborative use of multi-UAVs for mapping can be used as an alternative to solve this problem, creating a cooperative navigation system. This system requires that individual local maps will be merged into a global map in a distributed way. In this context, this work proposes a system for merging three-dimensional occupancy grid maps for use in UAVs that compose a cooperative navigation system. The proposed solution consists of a keypoint detector, a keypoint descriptor, and filters for keypoints and correspondences. The keypoint properties, such as orientation, are acquired from potential field gradients.Image processing techniques are applied to remove the map noise and better calculate the transformation parameters. The proposed system is validated by a set of simulation experiments performed in six different environments (indoor and outdoor). First, each component of the proposed system is individually evaluated. Then, the complete pairwise map merging system is evaluated. Finally, the appropriate functioning of the proposed system is validated through a visual evaluation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.