According to the researchers, they were able to achieve this goal with S-band waves, which have about the same wavelength as wireless internet. The apparatus they came up with uses 13 transmitting antennas for signal amplification purposes as well as eight receiving antennas. Targets are displayed by elimination of certain objects. For example, a wall that is 20 feet away would show in a certain frequency range that can be filtered from the video. Objects behind the wall, however, would show up on a screen.
The entire system is small enough to be mounted on top of a military vehicle, the MIT researchers said. The demo system worked at a range of 20 feet and delivered through-the-wall video at 10.8 fps. A production system could achieve a range of about 60 feet.
There is a clear military purpose to this technology and has obvious benefits. However, if the invention makes its way to government and general residential applications, there could be an entire new wave of privacy concerns.