Outsmart the Outdoors
Nuisance alarms can minimize the benefits of video analytics
- By John Romanowich
- Feb 03, 2010
Proponents of video analytics
claim the technology can boost
the productivity of security staff
by alerting them to take action in the
event an incident occurs according to
predetermined rules. In theory, this
enables fewer officers to oversee larger
coverage areas by freeing them from
perpetually watching an increasing
number of video displays and make
intelligent response decisions when security
violations occur. And for many
indoor surveillance applications, this is
often the case.
When it comes to outdoor surveillance,
too often, the reality is different.
In many cases, the security officer who
was supposed to be more efficient now
spends his time dealing with nuisance
alarms when a gust of wind or a change
in lighting triggers an alarm. As a result,
officers come to distrust the system
and may tune down the detection
sensitivity or even turn off the alarms
altogether.
Some facilities deal with hundreds
of nuisance alarms every week. One
reason is that video analytics is often
used in outdoors applications for which
they weren't designed.
The key to eliminating nuisance
alarms in outdoor applications is to
use technology properly designed for
the outdoors rather than misapplying
analytics intended for more controlled
indoor surroundings. Using intelligent
video to secure large outdoor venues
requires specific technologies like
sufficient onboard camera processing
power to overcome lighting and
weather issues, accurately detect and
track legitimate targets from extraneous
surrounding motion and clutter,
and employ geographic information
system coordinates to determine a
target's location, size and velocity. Applying
the appropriate technology to
the task enables the full realization of
the long-promised benefits of intelligent
video and delivers new levels of
efficiency for the $100 billion security
guard market.
Outdoors vs. Indoors
In addition to large coverage areas typically
associated with outdoor venues,
there are many environmental influencers
that need to be addressed. Changing
lighting conditions and sources of
motion caused by weather or vibrations
can wreak havoc with conventional indoor
detection software when applied
outdoors. To cover expansive outdoor
areas, cameras are often mounted on
poles or rooftops, where even slight
winds can cause vibrations, impacting
detection accuracy. Other problems
include landscape clutter, reflections
and even ripples in water, along with
random video "noise" that can conceal
targets of interest or simply cause cameras
to ignore them. All of these problems
are magnified when attempting to
detect targets that vary greatly in size
across large fields of view.
Indoors, a camera sees a limited
field of view in typically controlled
surroundings. It's a mistake to apply
the same technologies to monitor critical
infrastructure applications such as
transportation, energy, utilities or large
campuses where conditions are continually
changing.
The economics of covering large
outdoor areas also are different. For example,
a standard metric used to justify
purchases and total cost of ownership
for indoor applications is often calculated
in terms of cost per camera. In
contrast, covering large outdoor venues
requires the creation of an outdoor
surveillance infrastructure, including
architectural design, permits, construction,
trenching, camera poles, network
connectivity, video display and storage.
The economic measure needs to
change from cost per camera to accurate
coverage per dollar. Cameras for
outdoor applications must cover large
areas and capture accurate information
over long distances to achieve security
objectives, minimize nuisance alarms
and help contain infrastructure costs.
They also need to be built to withstand
extreme environmental conditions such
as rain, snow and humidity.
A Technology Solution
Although outdoor video surveillance
applications are challenging, it is possible
to deploy automated outdoor systems
to deliver high-accuracy detection
of targets over a large area while greatly
reducing nuisance alarms. Such an approach
unlocks the full capability of intelligent
video for use outdoors and as
a guard multiplier for detecting, locating
and assessing threats in real time.
To achieve success outdoors, intelligent
camera systems need to integrate
the necessary processing power at the
edge to eliminate camera motion for accurate
detection and to remove motion
as a source of nuisance alarms. It is diffi
cult for video analytics software to tell
if an intruder has entered into view if
the whole scene is moving due to wind.
Sufficient in-camera processing also
can eliminate water and tree motion
as a source of nuisance alarms and
dynamically correct lighting to detect
events that would otherwise be missed.
Additional environmental factors that
need to be addressed in the processing
chain include the sun moving across the
sky, clouds constantly in motion and
shadows moving through a scene.
Another important feature for outdoor
camera systems is the need to
provide accurate location/positioning
information to aid with threat assessment
and to ensure a rapid response.
Systems employing GIS-based analytics
have the ability to superimpose the
threat location directly on a map of the
facility, while utilizing this information
to set security rules based on target size
and velocity. GIS information also can
enable automatic positioning of a PTZ
camera to provide an up-close view of a
target—particularly important in large
outdoor areas—and highly detailed images
for forensic investigations.
Applying the right technologies to
video surveillance systems can transform
the performance and economics
of outdoor security. Reductions in
design, construction and installation
costs also are possible when truly intelligent
long-range cameras provide
wide-area coverage with accurate data.
The resulting solution will be trustworthy,
drastically reduce nuisance alarms
and represent a truly cost-effective surveillance
technology for high-security
applications.