Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A camera that peers around corners

21.03.2012
A new imaging system could use opaque walls, doors or floors as 'mirrors' to gather information about scenes outside its line of sight

In December, MIT Media Lab researchers caused a stir by releasing a slow-motion video of a burst of light traveling the length of a plastic bottle. But the experimental setup that enabled that video was designed for a much different application: a camera that can see around corners.

In a paper appearing this week in the journal Nature Communications, the researchers describe using their system to produce recognizable 3-D images of a wooden figurine and of foam cutouts outside their camera's line of sight. The research could ultimately lead to imaging systems that allow emergency responders to evaluate dangerous environments or vehicle navigation systems that can negotiate blind turns, among other applications.

The principle behind the system is essentially that of the periscope. But instead of using angled mirrors to redirect light, the system uses ordinary walls, doors or floors — surfaces that aren't generally thought of as reflective.

The system exploits a device called a femtosecond laser, which emits bursts of light so short that their duration is measured in quadrillionths of a second. To peer into a room that's outside its line of sight, the system might fire femtosecond bursts of laser light at the wall opposite the doorway. The light would reflect off the wall and into the room, then bounce around and re-emerge, ultimately striking a detector that can take measurements every few picoseconds, or trillionths of a second. Because the light bursts are so short, the system can gauge how far they've traveled by measuring the time it takes them to reach the detector.

The system performs this procedure several times, bouncing light off several different spots on the wall, so that it enters the room at several different angles. The detector, too, measures the returning light at different angles. By comparing the times at which returning light strikes different parts of the detector, the system can piece together a picture of the room's geometry.

Off the bench

Previously, femtosecond lasers had been used to produce extremely high-speed images of biochemical processes in a laboratory setting, where the trajectories of the laser pulses were carefully controlled. "Four years ago, when I talked to people in ultrafast optics about using femtosecond lasers for room-sized scenes, they said it was totally ridiculous," says Ramesh Raskar, an associate professor at the MIT Media Lab, who led the new research.

Andreas Velten, a former postdoc in Raskar's group who is now at the University of Wisconsin at Madison, conducted the experiments reported in Nature Communications using hardware in the lab of MIT chemist Moungi Bawendi, who's collaborating on the project. Velten fired femtosecond bursts of laser light at an opaque screen, which reflected the light onto objects suspended in front of another opaque panel standing in for the back wall of a room.

The data collected by the ultrafast sensor were processed by algorithms that Raskar and Velten developed in collaboration with Otkrist Gupta, a graduate student in Raskar's group; Thomas Willwacher, a mathematics postdoc at Harvard University; and Ashok Veeraraghavan, an assistant professor of electrical engineering and computer science at Rice University. The 3-D images produced by the algorithms were blurry but easily recognizable.

Raskar envisions that a future version of the system could be used by emergency responders — firefighters looking for people in burning buildings or police determining whether rooms are safe to enter — or by vehicle navigation systems, which could bounce light off the ground to look around blind corners. It could also be used with endoscopic medical devices, to produce images of previously obscure regions of the human body.

In its work so far, Raskar says, his group has discovered that the problem of peering around a corner has a great deal in common with that of using multiple antennas to determine the direction of incoming radio signals. Going forward, Raskar hopes to use that insight to improve the quality of the images the system produces and to enable it to handle visual scenes with a lot more clutter.

Written by Larry Hardesty, MIT News Office

Caroline McCall | EurekAlert!
Further information:
http://www.mit.edu

More articles from Power and Electrical Engineering:

nachricht Did you know that the wrapping of Easter eggs benefits from specialty light sources?
13.04.2017 | Heraeus Noblelight GmbH

nachricht To e-, or not to e-, the question for the exotic 'Si-III' phase of silicon
05.04.2017 | Carnegie Institution for Science

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>