Site-specific weed management in corn using UAS imagery analysis and computer vision techniques

TL;DR

This study develops a site-specific weed management system using UAS imagery and computer vision to identify weeds and optimize herbicide application, reducing chemical use by over 26% in corn fields.

Contribution

It introduces a novel Crop Row Identification algorithm and a complete workflow from aerial imaging to targeted weed control in commercial corn production.

Findings

Saved 26.23% of herbicide application area.

Successfully identified weed distribution using UAS imagery.

Implemented targeted spraying with commercial sprayer.

Abstract

Currently, weed control in commercial corn production is performed without considering weed distribution information in the field. This kind of weed management practice leads to excessive amounts of chemical herbicides being applied in a given field. The objective of this study was to perform site-specific weed control (SSWC) in a corn field by 1) using an unmanned aerial system (UAS) to map the spatial distribution information of weeds in the field; 2) creating a prescription map based on the weed distribution map, and 3) spraying the field using the prescription map and a commercial size sprayer. In this study, we are proposing a Crop Row Identification (CRI) algorithm, a computer vision algorithm that identifies corn rows on UAS imagery. After being identified, the corn rows were then removed from the imagery and the remaining vegetation fraction was classified as weeds. Based on that information, a grid-based weed prescription map was created and the weed control application was implemented through a commercial-size sprayer. The decision of spraying herbicides on a particular grid was based on the presence of weeds in that grid cell. All the grids that contained at least one weed were sprayed, while the grids free of weeds were not. Using our SSWC approach, we were able to save 26.23\% of the land (1.97 acres) from being sprayed with chemical herbicides compared to the existing method. This study presents a full workflow from UAS image collection to field weed control implementation using a commercial-size sprayer, and it shows that some level of savings can potentially be obtained even in a situation with high weed infestation, which might provide an opportunity to reduce chemical usage in corn production systems.