Friday, July 11, 2014
Inexpensive MIT Built 3D Imager Helped Create the Microsoft Kinect and Has Military Applications
MIT News Office Known simply as the "nano-camera" this $500 device developed by the MIT Media Lab cost a fraction of what conventional 3D imaging machines do by calculating 'Time Of Flight' of low level visible spectrum lasers. The lasers are not powerful enough to cause damage to the eye and flash fast enough to not be perceived by the human brain.
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, “We use a new method that allows us to encode information in time,” says Ramesh Raskar, an associate professor of media arts and sciences and leader of the Camera Culture group within the Media Lab, “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.”
Based on a $500,000 'trillion frames per second' 'femto-camera', 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.
So while the practical uses for this technology has found its way to Microsoft's Kinect 2.0, military application could find mil-spec night vision goggles being replaced by these 3D nano-cameras.