We are quickly perfecting devices that can see behind walls. The latest incarnation of this superspy tech uses radio waves and simulated chaos to pinpoint objects that can't be seen.
Radar has been, for quite some time, a good way to see things that aren't in view. The waves are durable and large, letting them bend around walls and return back to their source loaded with information. The way the waves hit and bounce off of objects in an obscured space allows them to carry a lot of intel back to their source. The receiver of the waves can be made so sensitive that it can sense distortions made by a person breathing, or even by a heartbeat.
In order to be sensitive, though, the radio has to filter out 'noise'. This noise can be caused by many different things, including the radio waves themselves bouncing off the many walls in a room and coming back to interfere with each other. This problems is most egregious with waves of the same length. Random noise added in to the outgoing waves helps them distinguish themselves. The problem is, random noise that goes out is hard to recognize and separate when it comes back. It takes a lot of processing power on the part of the computer attached to the receiver to make the signal clear.
The solution comes in the form of faked randomness. Scientists have worked out an algorithm to make noises that sound random, but are actually a recognizable pattern that a computer can match easily once it has received it. The device that makes the noise is called a 'chaotic oscillator,' and it has many advantages. Not only is it fast and accurate, but many can be used in one area without interfering with each other. It's hoped that this technology can be used to find survivors of disasters in wreckage too dangerous or difficult to search.
Via New Scientist.