From the regular physics news update.
I wonder if they can use this for the JFK thing? Did they get enough audio sources?
PHYSICS NEWS UPDATE
The American Institute of Physics Bulletin of Physics News
Number 687 June 4, 2004 by Phillip F. Schewe, Ben Stein
REVERSING TIME TO CATCH SNIPERS. At last week's 75th anniversary
meeting of the Acoustical Society of America in New York City,
researchers presented a system that uses "time-reversed" acoustics
to pinpoint the exact locations of gunfire and explosions in an
urban environment. Coming from the U.S. Army's Cold Regions
Research and Engineering Laboratory and the University of
Connecticut, the researchers (Donald.G.Albert@erdc.usace.army.mil
and Lanbo.Liu@erdc.usace.army.mil) tested the system in a small
"training" village consisting mainly of two-story concrete-block
buildings. In their tests, they fired a gun at an arbitrary location
within the village. The gunshot echoed from building walls and
other surfaces. A network of simple audio sensors recorded the
reverberations at unique vantage points. The researchers then
turned to a computer, which contained a 2-D computer model of the
village. Inside this "virtual village," the computer generated a
backwards version of each recorded sound wave. Displaying a map of
the village, the computer broadcasted the time-reversed waves from
the locations corresponding to the sensors that recorded the
original waves. In the computer map of the village, the
time-reversed waves eventually returned and converged at the spot
corresponding to the source of the gunshot. The researchers are
hoping to develop the system for real-world use, for example by
reducing the amount of computer processing time associated with the
procedure so that it can potentially pinpoint snipers and explosions
in real-time. (Paper 5aPAb5; pictures, movies and lay-language text
at
http://www.acoustics.org/press/147th/liu-albert.html)