A $500 "nano-camera" that can operate at the speed of light has been developed by researchers in the MIT Media Lab.
The three-dimensional camera, which was presented last week at Siggraph Asia in Hong Kong, could be used in medical imaging and collision-avoidance detectors for cars, and to improve the accuracy of motion tracking and gesture-recognition devices used in interactive gaming.
The camera is based on "Time of Flight" technology like that used in Microsoft's recently launched second-generation Kinect device, in which the location of objects is calculated by how long it takes a light signal to reflect off a surface and return to the sensor. However, unlike existing devices based on this technology, the new camera is not fooled by rain, fog, or even translucent objects, says co-author Achuta Kadambi, a graduate student at MIT.
"Using the current state of the art, such as the new Kinect, you cannot capture translucent objects in 3-D," Kadambi says. "That is because the light that bounces off the transparent object and the background smear into one pixel on the camera. Using our technique you can generate 3-D models of translucent or near-transparent objects."
In a conventional Time of Flight camera, a light signal is fired at a scene, where it bounces off an object and returns to strike the pixel. Since the speed of light is known, it is then simple for the camera to calculate the distance the signal has travelled and therefore the depth of the object it has been reflected from.
Unfortunately though, changing environmental conditions, semitransparent surfaces, edges, or motion all create multiple reflections that mix with the original signal and return to the camera, making it difficult to determine which is the correct measurement.
Instead, the new device uses an encoding technique commonly used in the telecommunications industry to calculate the distance a signal has travelled, says Ramesh Raskar, an associate professor of media arts and sciences and leader of the Camera Culture group within the Media Lab, who developed the method alongside Kadambi, Refael Whyte, Ayush Bhandari, and Christopher Barsi at MIT and Adrian Dorrington and Lee Streeter from the University of Waikato in New Zealand.
"We use a new method that allows us to encode information in time," Raskar says. "So when the data comes back, we can do calculations that are very common in the telecommunications world, to estimate different distances from the single signal."
The idea is similar to existing techniques that clear blurring in photographs, says Bhandari, a graduate student in the Media Lab. "People with shaky hands tend to take blurry photographs with their cellphones because several shifted versions of the scene smear together," Bhandari says. "By placing some assumptions on the model — for example that much of this blurring was caused by a jittery hand — the image can be unsmeared to produce a sharper picture."
The new model, which the team has dubbed nanophotography, unsmears the individual optical paths.
In 2011 Raskar's group unveiled a trillion-frame-per-second camera capable of capturing a single pulse of light as it travelled through a scene. The camera does this by probing the scene with a femtosecond impulse of light, then uses fast but expensive laboratory-grade optical equipment to take an image each time. However, this "femto-camera" costs around $500,000 to build.
In contrast, the new "nano-camera" probes the scene with a continuous-wave signal that oscillates at nanosecond periods. This allows the team to use inexpensive hardware — off-the-shelf light-emitting diodes (LEDs) can strobe at nanosecond periods, for example — meaning the camera can reach a time resolution within one order of magnitude of femtophotography while costing just $500.
"By solving the multipath problem, essentially just by changing the code, we are able to unmix the light paths and therefore visualize light moving across the scene," Kadambi says. "So we are able to get similar results to the $500,000 camera, albeit of slightly lower quality, for just $500."
Abby Abazorius | EurekAlert!
Researchers take next step toward fusion energy
16.11.2017 | Texas A&M University
Desert solar to fuel centuries of air travel
16.11.2017 | SolarPACES
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
17.11.2017 | Physics and Astronomy
17.11.2017 | Health and Medicine
17.11.2017 | Studies and Analyses