International team of researchers spearhead research into new sensor system for remote crop monitoring

A new compact lightweight sensor system with infrared imaging is in the works to help growers with remote crop monitoring. Engineers from RMIT University, the City University of New York, the University of Melbourne and the ARC Centre of Excellence for Transformative Meta-Optical Systems have all joined forces to create and research the new sensor system, which can help farmers pinpoint which crops need pest control, fertilisation and irrigation. This prevents the need for a “one-size-fits-all” approach and according to RMIT could result in cheaper groceries by boosting harvests. The sensor systems works by switching from edge detection (imaging the outline of an object) and extracting infrared information. The technology also includes a filter made with a thin layer of vanadium dioxide, an inorganic compound used in tools such guidance systems and infrared modulators. TMOS chief investigator professor Madhu Bhaskaran, who engineered the prototype sensor system, said materials such as vanadium dioxide add a “fantastic tuning capability” to advance technology. “When the temperature of the filter is changed, the vanadium dioxide transforms from an insulating state to a metallic one, which is how the processed image shifts from a filtered outline to an unfiltered infrared image,” she said. “These materials could go a long way in futuristic flat-optics devices that can replace technologies with traditional lenses for environmental sensing applications — making them ideal for use in drones and satellites which require low size, weight and power capacity.” Lead author Michele Cotrufo said a few recent demonstrations had achieved analogue edge detection using meta surfaces and most of the devices demonstrated so far were static. “Their functionality is fixed in time and cannot be dynamically altered or controlled,” he said. “Yet the ability to dynamically reconfigure processing operations is key for meta surfaces to be able to compete with digital image processing systems. This is what we have developed.” Co-author PhD scholar Shaban Sulejman said the design and materials used made the technology easier to mass-manufacture and growers might not have to wait too long for the sensor system to be made available to purchase. “It also operates at temperatures compatible with standard manufacturing techniques, making it well-placed to integrate with commercially available systems and therefore move from research to real-world usage rapidly,” he said.