A compact, lightweight sensor system with infrared imaging capabilities developed by an international team of engineers could be easily fitted to a drone for remote crop monitoring.

This flat-optics technology has the potential to replace traditional optical lens applications for environmental sensing in a range of industries.

This innovation could result in cheaper groceries as farmers would be able to pinpoint which crops require irrigation, fertilization and pest control, instead of taking a one-size-fits-all approach, thereby potentially boosting their harvests.

The sensor system can rapidly switch between edge detection—imaging the outline of an object, such as a fruit—and extracting detailed infrared information, without the need for creating large volumes of data and using bulky external processors.

The capability to switch to a detailed infrared image is a new development in the field and could allow farmers to collect more information when the remote sensor identifies areas of potential pest infestations.

This research by engineers at the City University of New York (CUNY), the University of Melbourne, RMIT University and the ARC Center of Excellence for Transformative Meta-Optical Systems (TMOS) is published in Nature Communications in a paper titled “Reconfigurable image processing metasurfaces with phase-change materials.”

How does the sensor system work?

The prototype sensor system, which comprises a filter made with a thin layer of a material called vanadium dioxide that can switch between edge detection and detailed infrared imaging, was engineered by TMOS Chief Investigator Professor Madhu Bhaskaran and her team at RMIT in Melbourne.

“Materials such as vanadium dioxide add a fantastic tuning capability to render devices ‘smart'”, she said.

“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.”

“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.

RMIT holds a granted US patent and has a pending Australian patent application for its method of producing vanadium dioxide films, which may be suitable for a broad range of applications.

Lead author Dr. Michele Cotrufo said the system’s ability to switch between processing operations, from edge detection to capturing detailed infrared images, was significant.

“While a few recent demonstrations have achieved analog edge detection using metasurfaces, most of the devices demonstrated so far are static. Their functionality is fixed in time and cannot be dynamically altered or controlled,” said Corufo, who conducted his research at CUNY.

“Yet, the ability to dynamically reconfigure processing operations is key for metasurfaces to be able to compete with digital image processing systems. This is what we have developed.”

Next steps

Co-author Shaban Sulejman from the University of Melbourne said the design and materials used make the filter amenable to mass-manufacturing.

“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.”

TMOS Chief Investigator Ann Roberts, also from the University of Melbourne, said flat optics technologies had the potential to transform countless industries.

“Traditional optical elements have long been the bottleneck preventing the further miniaturization of devices. The ability to replace or complement traditional optical elements with thin-film optics breaks through that bottleneck.”

Nate Greene, an engineer at Towson’s Stanley Black & Decker, calls the innovation “extremely atypical.”

A group of students from Johns Hopkins University signed onto a class project and were tasked with building a new product for the multinational tool company. And they actually did it.

Using a campus 3D printer, a team of four seniors at Hopkins designed a new attachment for leaf blowers, capable of quieting some of the harshest decibels of a blower’s sound.

“The university’s focus is so theoretical,” said Greene, who advised the students on their design. “So to find a group that understands the right ways to apply that theory right off the bat … The team has been not only good at the content they’re working on but good at just working through changing projects.”

The attachment is a cylindrical nozzle, which allows most of the air from the blower to pass through but directs some of it into thin, helical channels, dampening the high-pitched whine typical of the neighborhood nuisance.

The students chose to target the most annoying part of the blower’s sound, said Madison Morrison, one of the mechanical engineering majors who helped create the design.

“We knew that if we could improve the noise quality—even though, obviously, with a blower system, it’s hard to completely eliminate noise—it’d be at least a more pleasant experience for your neighbors trying to sleep in or yourself even as the user,” she said.

On the cusp of their graduation, the students filed for a patent, and the invention is on its way to manufacturing at Stanley, expected to hit store shelves in about 2026, Greene said.

“The design is super unique. We haven’t seen really anything like this in the industry,” Greene said. “Because it is so novel, the team’s been able to file a patent. The design is patent-pending, which is a huge step.”

The students developed their prototype for a specific DeWalt electric blower, Greene said. Now, the company is evaluating whether their attachment could work for other blowers, too.

When the students began working on the project last August, their mission was simply to quiet the blower. They weren’t sure how they’d accomplish it.

At the outset, they had different options, including taking an “active” or “passive” approach, said Michael Chacon, one of the students on the project. The former would be akin to noise-canceling headphones, which generate competing sound waves to cancel out noise. The latter would be similar to a gun silencer, which doesn’t cancel out the sound but dampens it. They chose the latter, hoping it would be easier to generate, prototype and install on the blower.

Once they decided they’d create an attachment, made of a type of plastic, they began testing different designs in the 3D printer. Their first iteration was shorter in length and had different shaped channels but already showed promise, Morrison said.

“We were like, ‘Wow, this design has so much potential,'” Morrison said. “Going from that drawing board to: This is in my hand and kind of works? Honestly, that is such a great feeling.”

By the end of the project, they’d created more than 40 different prototypes in blue, red, green orange and pink using campus 3D printers. Among the considerations was balancing the performance of the blower with the performance of the noise cancellation, Morrison said.

“If you just slap a muffler on here, well, you’re probably not going to blow many leaves,” Morrison said.

Under the program, Stanley Black & Decker will have the patent, Greene said. The students will not profit from the design but will be listed as inventors, an invaluable resume-builder for young mechanical engineers, Greene said.

For their part, the students were thrilled that their idea might go to market.

“It’s really exciting to see that something that we made in this class is actually likely going to go to market,” said one of the students, Andrew Palacio. “It would have been really easy for this project to not go anywhere. I think it’s pretty rare for even some of the better projects that students make to actually become a product.”

Even if they don’t have yards, the students might find themselves buying leaf blowers a few years from now, said one of the students, Leen Alfaoury.

“You could put it on one of those museum clear glass stands,” she joked.

2024 The Baltimore Sun. Distributed by Tribune Content Agency, LLC.