A hot plant is an early warning sign of an under-watered, unhealthy plant, which makes monitoring crop temperatures a priority for many farmers. But to do so, they need the right equipment.

Infrared cameras can detect heat and convert it into an image, but they’re large, unwieldy, and expensive. Infrared sensors are less expensive, but they don’t provide images, which makes accurate monitoring difficult for medium and large-sized fields.

Now, researchers have developed a new approach that provides precise, visual crop temperature data at a lower cost. Combining a regular digital camera with a miniature infrared camera into a specially engineered structure, the system can provide both temperature data and detailed images, giving farmers a large amount of information about their crops.

An image from the digital camera is combined with one from the miniature infrared camera to form a complete picture of the temperature of an area of crops.
An image from the digital camera is combined with one from the miniature infrared camera to form a complete picture of the temperature of an area of crops.
Image: U. Missouri

“Using an infrared camera to monitor crop temperature can be tricky because it is difficult to differentiate between the plants and background elements like soil or shade,” says Ken Sudduth, an adjunct professor of bioengineering at the University of Missouri’s College of Agriculture, Food and Natural Resources and an agricultural engineer for the US Department of Agriculture.

“By augmenting a miniature infrared camera with a digital camera, we created a system that can examine crop temperatures with great detail and accuracy.”

As reported in Computers and Electronics in Agriculture, the cameras together produce two distinct images of the same area: a visually detailed photograph and an infrared image. The setup, called the Multi-band System for Imaging of a Crop Canopy, allows farmers to identify problem areas from the digital camera images and analyze those areas with infrared images that map temperature to light intensity.

Coupled with an algorithm that automatically filters soil, shade, and other non-plant presences from the images, the camera system would allow farmers to precisely irrigate their crops according to the specific needs of individual plants, maximizing yields and optimizing water use without requiring the purchase of more expensive infrared cameras.

“Medium-scale farmers have big fields, but they don’t always have the funds for expensive monitoring equipment,” Sudduth says. “Our system allows for precision monitoring over a large area for a more manageable cost. That’s good for farmers who can earn a bigger profit, and it’s good for everyone who depends on their crops.”

The system needs more fine-tuning before it can be sold to farmers, and future iterations could incorporate drones for increased versatility.