Say you’re an agricultural scientist, and you know there’s technology out there that could be a game-changer in your research. But its application in agriculture is still relatively new, so finding someone who can help you use it is challenging.
That’s the case with thermal remote sensing technology — equipping UAVs with thermal sensors that produce images of fields based on temperature, and processing that data for researchers to analyze and apply.
Purdue’s Plant Sciences team has now established a protocol to enable application of UAV-based remote sensing thermal imaging. The protocol takes advantage of the innovative UAV technologies provided by GRYFN, a company founded at Purdue, and is capable of providing information-rich data for scientists in different disciplines.
“Our goal is to establish a protocol that agriculture researchers can rely on,” says Sungchan “Sun” Oh, computational infrastructure specialist on the Plant Sciences team led by Mitch Tuinstra, Wickersham Chair of Excellence in Agricultural Research and scientific director of Purdue’s Institute for Plant Sciences, and Yang Yang, director of digital phenomics.
Many agricultural researchers have adopted remote sensing technologies in which UAVs carry sensors that allow them to not only view fields from the air but also measure the structural and functional characteristics of crops. Their usefulness is applicable to a wide range of areas that the researchers study — plant varieties, irrigation, different fertilizers or pesticides, and many more.
For applications in agriculture, reliable processing protocols have made RGB and LiDAR the go-to UAV-based sensors. From RGB remote sensing, measurements show how green the plot is. LiDAR measures detailed geometric properties, like plant height or volume. However, applying thermal sensors to reliably measure the surface temperature of a target, which cannot be assessed by visual observation, has been more challenging.
Thermal properties of a crop cannot be extracted from other remote sensors such as the RGB imager or LiDAR. Thermal images also look different, so transforming the raw thermal data into a human-friendly format requires carefully established processes.
“After several intricate steps, we can finally measure temperature using the acquired thermal images of a target. Think of it like measuring temperature with your eyes,” Oh explains. “Brighter colors like orange mean higher temperatures, while darker ones such as indigo or purple represent areas of lower temperatures. We just do it almost automatically with our processing algorithm.”
Based on the thermal measurements, a researcher investigates the correlation between their interests of research — for example, amount of fertilizer or different corn varieties — with temperature.
Temperature information is crucial because it is closely related to a plant’s health status and performance. “It can be associated with a corn plant’s height, leaf size, growth rate, yield, and even taste. Temperature could also be the key to reveal underlying reasons why some varieties do well in a certain difficult conditions, while others don’t,” Oh explains.
Researchers are still learning how to apply thermal data to their own studies. “Our Plant Sciences team is trying to become a bridge between the agricultural scientist and the technologies behind the scene,” Oh says. “We’re trying to provide accurate, usable, actionable data for agricultural researchers.”
Their goal is not a sophisticated product, he adds: “Our protocol is trying to create a thermal data product that researchers can easily use with prior knowledge and skills.”
Click here to read more purdue.edu
Photo Credit: igor-stevanovic
Categories: Indiana, Weather