Wi-Vi: Exploiting Known Technology

This is really neat.  Apparently in our information age, WiFi can transmit information in more ways than you might realize.  While 1's and 0's might transmit on the waves, have you ever thought about the propagation properties and the information that can be gleaned and derived from it?

A fairly extensive article over on CIMSEC offers the following description on Wi-Vi:

Using an encrypted WiFi signal to differentiate the 2.4 GHz signal from white noise, multiple signals are fired into a room, reflected back, and processed. When nothing is moving, the signal is zeroed out. When objects moves, the signal changes. For each thing moving, there is a separate discernible changed return in signal, allowing the system to detect multiple objects or people¹

This really got me thinking.  What makes this really cool is the discerning of additional information from a physical technology that is already (and widely) in use.

So... what other mediums are already in use that science can exploit?  And the purpose of exploitation is all a matter of perspective.  Just as I mentioned previously, the physical HF that Karl Dönitz utilized for his intimate command and control during battles as well as continuous U-boat status updates in WWII, was viewed by the Allies as gold mine of intelligence.

In a time of budget constraints, how best can we utilize our present technologies in ways that might seem a bit nontraditional or unconventional?

There are two main stages for this discussion and Wi-Vi could really stand on either one.  The first, and probably more familiar to the military, is as in the HF example above, exploiting other's technology.  The other, which is possibly a more difficult yet immediately rewarding stage is exploiting our own technology.

As for Wi-Vi, enjoy the demonstration video below.


References
Image,¹ http://cimsec.org/wi-vi-people-radar-for-boarding-teams/