Relying on advances 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, according to an article on the U.S. Army website. The enhanced sensitivity makes 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, according to the article. The IR polarimetric camera, called Pyxis, can distinguish the polarization signature of manmade objects from that of natural backgrounds.
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To create the IR polarimetric camera, researchers integrated 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.
The researchers spent a significant amount of effort on refining the camera’s assembly 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.
"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 also hope 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 infrared camera for drones could also prove useful for different commercial applications, such a detecting oil spills with oil as thin as 50 micrometers, even in the presence of waves and emulsifiers used in spill clean-ups.
Researchers and their commercial partners are also combining the camera's unique polarization imagery with machine learning algorithms in order to improve its capabilities.