Camera Captures Images Around Corners

Researchers at the Massachusetts Institute of Technology have developed a prototype of a camera that can capture images of objects that are not directly in the line of sight.

Called a "Femtosecond Transient Imaging system," the prototype can look around corners and pulse a laser beam at extremely short time scales, about one-quadrillionth of a second. It then computes the time and distance that each pixel travels by continuously collecting light to make a 3D image of the scene. While traditional cameras estimate intensity per pixel, "our transient imaging camera prototype captures a 3D time image for each pixel and uses an ultra-short pulse laser for flash illumination," said researcher Ahmed Kirmani, in a thesis paper describing the camera.

Ramesh Raskar, an associate professor at MIT who is Kirrmani's adviser, described the concept behind the device as similar to a CAT scan, which takes photographs and puts images together with an "inverse geometry problem." Using an example of a room with an open door, Raskar said the device directs the laser beam at the door, which then scatters the light inside the room. Objects inside the room reflect the laser light from all surfaces back to the door and toward the transient imaging camera, The Hindu newspaper reported.

The camera is in the experimental stage of development, and MIT researchers are working on mapping more complex scenes. Columbia University Professor Shree Nayer told the BBC News that what hasn’t yet been made clear is "what complexities of invisible scenes are computable at this point."

Looking forward, the transient imaging framework "provides opportunities to accomplish tasks that are well beyond the reach of existing imaging technology," Kirmani wrote, noting that the ability to view hidden elements will "create a range of new computer vision opportunities." Possible applications for the camera could be medical imaging, especially with endoscopes that would pick up obstacles inside the body, search-and-rescue missions, vehicle collision avoidance and industrial environments.