Whether it's a slow-speed chase on a California freeway or a law-
enforcement agency seeking to spot people doing bad things, computer
technology is bringing high definition images down to earth.
The pictures are so sharp, Alan Purwin of Van Nuys, California, says,
that you can read the license plate on a vehicle from 7,000 feet in
the air. That kind of detail can either make for great television or
serious crime stopping.
Mr. Purwin is an Indiana-born pilot and entrepreneur who's spent most
of the past 30 years literally up in the air as a helicopter pilot.
He owns Helinet Aviation, a firm that leases helicopters as well as
develop highly specialized equipment for them, as well as Cineflex,
which develops the systems that capture and transmit the video.
Most recently, Mr. Purwin and his colleagues achieved some notoriety
for their work during Hurricane Katrina, showing images of levees
collapsing and the resulting flood damage. Though it wasn't their
idea, the Helinet choppers became the "pool" helicopter video feed
for all the major networks. And unlike the Hollywood movies his firm
has also worked on, the devastation of the hurricane was all too real.
"Flying around the affected areas from Katrina was different from
anything I've experienced in my life," Mr. Purwin said in a telephone
interview Nov. 10. "We didn't go there to be the news pool
helicopter, we went there because we thought it was the right thing
What they use is a helicopter equipped with a gimbal that
Cineflex has developed. A gimbal looks like a ball on the end of a
tube; in this case it can do a couple of interesting things. One is
to accommodate very long lenses, which is the basis for the license
plate-reading claim. The other is that the gimbal pivots in just
about every which way, making it extremely useful in terms of
positioning the camera, as well as following action on the ground,
such as when the slow-speed chase driver jumps out and starts running.
The other technology innovations are more related to computers: a
portable PC running Microsoft Corp.'s Windows CE operating system
controls video matters inside the aircraft, including the compression
and transmission of the high definition images, which are 300 megabit
streams that drop down to 19.3 megabits, saving a lot of transmission
The video compression issue isn't minor, Mr. Purwin said. If an
analog video signal has some problems, a viewer might see "snow" in
the picture. In high-definition television, if there are lost bits of
data, the whole picture is lost.
Outside, a gyroscope-based antenna system, also computer guided,
locks onto a ground station so images are received. On the ground,
the signal is restored to its high-def format.
Mr. Purwin said his firm is the "first to take high definition video
from an aerial, wireless environment, compress it for digital
microwave and decompress it at the download site, maintaining
Such capabilities will be important as television stations nationwide
switch to HDTV, but they can also be used by military and law
enforcement agencies to monitor activities on the ground. The firm
has sold a number to police and government agencies - a federal
client he can't name has acquired three customized helicopters,
which, Mr. Purwin said, could be flown in a C-130 cargo aircraft to
remote locations if needed.
The future holds other technologies that will likely aid law
enforcement users, said Ron Magocsi, Helinet Aviation's engineering
director. One challenge is the limited microwave spectrum available;
Mr. Magocsi, a longtime television news engineer, is looking at other
ways of getting the signal to where it needs to go.
I'm impressed that a Windows CE device can play traffic cop in the
midst of this hardware, but it's also worth noting that the Cineflex
and Helinet firms' technology could have some significant impact on
what we watch as entertainment and what law enforcement watches to
keep us safe. More information can be found at http://www.helinet.com