DECEMBER 2, 2019 – Army researchers enhanced the military’s capabilities to detect and identify hidden targets with a new advancement in thermal imaging technology.
Scientists at the U.S. Army Combat Capabilities Development Command’s Army Research Laboratory partnered with Polaris Sensor Technologies to develop a specialized infrared camera that incorporates polarization sensitivity, making it easier to find targets camouflaged in natural clutter than with thermal imaging alone.
Based on the properties of thermal electromagnetic radiation emitted light, each object possesses a distinctive polarization signature depending on the object’s surface properties and shape. The IR polarimetric camera, called Pyxis, is capable of distinguishing the polarization signature of manmade objects from that of natural backgrounds.
“The Pyxis camera offers significant benefits in target detection and clutter suppression over conventional uncooled infrared cameras without any increase in size, weight or power,” said Dr. David Chenault, president of Polaris Sensor Technologies.
Researchers created the IR polarimetric camera by integrating a pixelated polarizing filter into what’s known as a microbolometer. This innovation allows the camera to detect polarization contrast in the environment even when thermal contrast isn’t present.
A significant amount of effort was focused on refining the assembly of the camera and implementing software upgrades that help users obtain a better understanding of the unique nature of the polarimetric data.
“The physics of polarization is complicated, and our software enables the user to quickly and easily explore how signatures are impacted by materials and geometry in the scene,” Chenault said. “The analytical tools in our software makes comparing the performance of image metrics in the polarimetric video easy.”
During the past decade, research efforts led by Army physicist Dr. Kristan Gurton have shown that fusing polarimetric information with conventional thermal imagery greatly enhances the technology’s ability to detect low observable targets hidden by natural clutter.
In addition, thermal polarimetry has also allowed researchers to conduct human identification and facial recognition in complete darkness, a feat previously thought to have been impossible.
“As we found more and more new applications for thermal polarimetric imaging, it only made sense to work on making the camera systems smaller, more rugged and cost-effective,” Gurton said.
Ultimately, the Army contracted Polaris to develop such a system. The resultant IR polarimetric camera has successfully demonstrated its capabilities in handheld, vehicle-mounted and UAS-mounted platforms in multiple field tests.
Army researchers have also expressed their plans to mount this new specialized camera on small rotary wing and fixed wing drones for surveillance purposes to improve situational awareness, force protection and warfighter effectiveness.
“The Pyxis camera is small enough to mount on Class 1 UAS,” Chenault said. “We even have a ‘drone kit’ for quick integration onto many off-the-shelf drones.”
As a small business-developed technology, the infrared camera for drones demonstrates a potential variety of different commercial applications.
One such application is the detection of oil spills. The polarization sensitivity is able to very effectively detect oil as thin as 50 micrometers even in the presence of waves and emulsifiers used in spill clean-ups.
Once deployed on a commercial airborne platform, these cameras may soon be used to monitor oil processing and transportation facilities, such as refineries, pipelines and transfer stations, as well as ports, harbors and shipping lanes.
The Pyxis camera also shows promise in detecting snakes for ecological rehabilitation. Initial tests in the Everglades have shown that IR polarization is one of the more effective ways to detect pythons which have become a significant problem as an invasive species in Florida. The drone-mounted Pyxis may be able to assist python hunters with finding snakes in inaccessible locations.
“We’re incredibly excited about both of these applications because of the positive impact they could have outside of the military,” Chenault said. “It’s not every day that you get to go on a snake hunt as part of your job.”
For both these applications, researchers are looking into incorporating man-in-the-loop interfaces and autonomous software that will allow the camera system to automatically send alerts with text and images whenever it detects the desired target.
Researchers and their commercial partners are also combining the camera’s unique polarization imagery with machine learning algorithms in order to improve its capabilities.
The IR polarimetric camera will only require a few more finishing touches before it is ready for deployment, Chenault said.
“We believe the capability is ready now; it just needs to be integrated in its final form onto the objective platforms,” he said. “Direct interaction with the right program offices will start the process to get the technology in the hands of the Soldier.”
By U.S. Army CCDC Army Research Laboratory Public Affairs