Most cameras capture visible light, but researchers at Harvard University’s John A. Paulson School of Engineering and Applied Sciences (SEAS) have just concocted a camera that can see what humans can’t — and it’s about as simple as the one inside a smartphone. The thumb-sized polarization camera captures the way light bounces and could be used for anything from enhancing the accuracy of self-driving cars and drones to boosting facial recognition.
Polarized light is the direction that light vibrates when hitting a surface. While people can’t see polarized light, some animals, including some types of shrimp, can. Detecting polarized light can help spot camouflaged objects, distinguish between man-made and natural objects of the same color and shape, aid in depth detection, and enhance contrast over the typical visible light camera.
The research group’s camera isn’t the first polarization camera, but the researchers managed to simplify the technology into a smaller design with no moving parts, which could potentially allow polarizing cameras to enter drones and even smartphones. The camera itself is thumb-sized while adding a lens and case creates a system that’s more lunch-box sized.
Rather than using moving parts, the SEAS-designed camera uses a metasurface. The microscopic nanopillars in the camera system direct the light based on polarization to form four separate images. Together, those images display polarization at each pixel in real time.
“Polarization is a feature of light that is changed upon reflection off a surface,” Paul Chevalier, a postdoctoral fellow at SEAS and co-author of the study, explained. “Based on that change, polarization can help us in the 3D reconstruction of an object, to estimate its depth, texture, and shape, and to distinguish man-made objects from natural ones, even if they’re the same shape and color.”
Demonstrating the camera, the researchers showed how the system could detect transparent objects. Shrinking down the polarizing camera has a number of potential real-world uses, starting with aiding the systems that help self-driving cars and drones detect the objects in their surroundings. The researchers said the system could also be used to analyze atmospheric chemistry, find camouflaged objects, aid in capturing a 3D image for facial detection and more.
“This research is game-changing for imaging,” Federico Capasso, senior author of the paper, said. “Most cameras can typically only detect the intensity and color of light but can’t see polarization. This camera is a new eye on reality, allowing us to reveal how light is reflected and transmitted by the world around us.”
The research was recently published in the journal Science.
