Once perfected, the system would differentiate between crops and weeds and spot treat only weeds. Texture analysis uses light and dark leaf areas to identify species, while shape analysis compares the leaf to others in its database. The system works best on young plants with new, fully exposed leaves near their canopy. Mature plants are more challenging because leaves in their complex canopies overlap and create shadows. The research could have economic and environmental payoffs.
Farmers traditionally apply herbicides to entire fields before planting or before weeds emerge.
Spot spraying treats only emerged weed patches, reducing the amount of herbicide used and decreasing potential water contamination from runoff or leaching. Machine vision could make spot spraying easier and more accurate. The U.S. Geological Survey's water center helps fund this research. The team wants to imitate the process of human perception for complex plant analysis. If they succeed, this technology could be used in machine vision systems to detect weeds amid crop plants so only weeds are sprayed.