Northwestern University scientists have created a new holographic camera that can see around corners and through scattering media like fog.
According to the scientists, their new method – synthetic wavelength holography – works by indirectly scattering coherent light onto hidden objects, which then scatters again and travels back to a camera.
From there, an algorithm reconstructs the scattered light signal to reveal the hidden objects.
Due to its high temporal resolution, this method could prove beneficial for imaging fast-moving objects, such as the beating heart through the chest, or speeding cars around a street corner.
While the method has obvious potential for noninvasive medical imaging, early-warning navigation systems for automobiles and industrial inspection in tightly confined spaces, the scientists believe potential applications are endless.
“Our technology will usher in a new wave of imaging capabilities,” says Northwestern’s Florian Willomitzer, first author of the study.
“Our current sensor prototypes use visible or infrared light, but the principle is universal and could be extended to other wavelengths.”
According to Willomitzer, the Northwestern technology is the first method for imaging around corners and through scattering media that combines high spatial resolution, high temporal resolution, a small probing area and a large angular field of view.
This means that the camera can image tiny features in tightly confined spaces as well as hidden objects in large areas with high resolution – even when the objects are moving.
“It’s like we can plant a virtual computational camera on every remote surface to see the world from the surface’s perspective,” says Willomitzer.
For people driving roads curving through a mountain pass or snaking through a rural forest, this method could prevent accidents by revealing other cars or deer just out of sight around the bend.
“This technique turns walls into mirrors,” notes Willomitzer. “It gets better as the technique can also work at night and in foggy weather conditions.”
Image and content: Northwestern University