July 16, 2012
New Technique Shoots Lights Around Corners
Lee Rannals for redOrbit.com - Your Universe Online
By shining light from a normal lamp through a highly scattering plastic film, the team was able to show-off exactly what they could do with spatial light modulators (SLMs).
"The ability to image through inhomogeneous media is extremely valuable in numerous applications, ranging from astronomic observation through the turbulent atmosphere to microscopic imaging in turbid tissues," the researchers wrote in the journal. "Between these extremes exist various mundane tasks such as looking at foggy scenes or peeking through shower curtains." It's good to see that they have their priorities straight.
The new trick uses SLMs to "under" the scattering that makes objects opaque or non-reflecting. During their example using a normal lamp, the team used a computer to finely tune the SLM unit they could see a clear image of the lamp through the film.
By keeping the SLM set this way, they were able to obtain clear images of other objects through the film. The SLM effectively turns the film back into a clear sheet.
"What we have shown is that you don't need lasers - everybody else was doing this with lasers, and we showed you can do it with incoherent light from a lamp or the Sun - natural light," senior author of the study Prof Yaron Silberberg told BBC News.
The team saw that the same approach can work in reflection, by bouncing off a scattering material.
They showed the technique works just as well when the light from an object bounces off a piece of paper.
"You can take a piece of wall and effectively turn it into a mirror, and this is the part that makes everybody raise an eyebrow," Silberberg told BBC.
He said the primary use for the technique will be in biological and medical studies, rather than just trying to see through thin materials or around corners.
"I don't want to say that it solves the problems of secret organizations and Peeping Toms and so on, that's not going to be so simple. But the principle is there," he told BBC. "We have not started to tackle these things... but I see how much interest this raises and think maybe we should."
This isn't the first time scientists have been trying to unravel the mysteries of Superman-like vision.
A camera that can "see around corners" was developed back in 2010, which used a series of laser pulses to illuminate a scene and work out what is around a corner from the timing of reflections.