Is it a bird, is it a plane? It's a Superman-like technology.
Though it might sound like something straight out of a comic book, the ability to peer through clouds and fog using something resembling x-ray vision is now possible for humans thanks to a new device developed by Stanford University researchers.
The researchers took a system similar to the ones that allow autonomous vehicles to "see" and enhanced it with an incredibly efficient algorithm that is able to reconstruct three-dimensional hidden objects based on the light particles' movements.
X-ray vision, or foam vision?
The researchers recently published a paper in Nature Communications, in which they demonstrated the fact that their system was able to reconstruct shapes obscured by 1-inch thick foam — something that would be akin to looking through a wall to the naked eye, and would be worthy of Superman.
"A lot of imaging techniques make images look a little bit better, a little bit less noisy, but this is really something where we make the invisible visible," Gordon Wetzstein, assistant professor of electrical engineering at Stanford University and senior author of the paper, explained in a press release.
"This is really pushing the frontier of what may be possible with any kind of sensing system. It’s like superhuman vision," he continued.
Though the technique essentially allows for objects to be seen behind visible barriers, it is most suited to large-scale situations, such as navigating self-driving cars in heavy rain or fog and satellite imaging of Earth or other planets through hazy conditions.
However, the researchers say that the technology can complement other systems for use in the microscopic scale and can, therefore, also be used for medical applications.
Detecting tiny particles of light
The system pairs a laser with a super-sensitive photon detector that records every bit of laser light that hits it. Obstructions such as fog, foam, or clouds, allow the occasional photon to pass through. So the system is able to pick up these tiny particles passing through these barriers, hitting the object behind it and bouncing back to the detector.
An algorithm then analyzes where and when the photons hit the detector in order to reconstruct the hidden objects in 3D.
"You couldn’t see through the foam with your own eyes, and even just looking at the photon measurements from the detector, you really don’t see anything," said David Lindell, a graduate student in electrical engineering and lead author of the paper. "But, with just a handful of photons, the reconstruction algorithm can expose these objects – and you can see not only what they look like, but where they are in 3D space."
Towards a better understanding of the universe
One day, a descendant of this technology could be used to navigate through other planets to help see through hazy conditions, icy clouds, and other visual barriers that would otherwise impede our understanding of what's out there.
Today, the researchers believe their system could make autonomous vehicles and other machines even safer and they aim to carry out more experiments and simulations in order to find the best use cases for their technology.
Lindell and Wetzstein emphasize the way that this work represents a deeply interdisciplinary intersection of science and engineering: "these sensing systems are devices with lasers, detectors, and advanced algorithms, which puts them in an interdisciplinary research area between hardware and physics and applied math,” Wetzstein explained. “All of those are critical, core fields in this work and that’s what’s the most exciting for me.”