Securing the Homeland
Thermal solutions proven to be a vital component of homeland security
Homeland Security never sleeps. It is a 24/7 operation that can’t afford downtime or periods of reduced readiness. Thermal security cameras have become the visual surveillance sensor of choice for these demanding, high-security missions.
For many years, thermal cameras have proven themselves to be the best 24-hour visual surveillance imaging solutions available, and today they are a vital component in our country’s vital homeland security mission, helping to secure our borders, airports, sea ports, nuclear facilities and other critical infrastructure installations.
Through dust and smog, even on the darkest nights, thermal cameras let security professionals see intruders and vehicles alike. No matter what they need to see, or where they need to see it from, thermal cameras keep law enforcement and security officers seeing clearly.
Night and Day
The tactical and practical advantages of thermal as the best solution for nighttime security imaging have been known for years. Their downside is their expense, which requires long budgetary intervals between acquisitions.
But the last few years have seen the cost of high-quality thermal security cameras come down dramatically, with models now available for as little as $3,000, greatly expanding their use in the security industry -- particularly in homeland security and critical infrastructure security applications.
The fact that thermal security cameras cost 10 percent of what they did a few years ago is only part of the story. It doesn’t take into account three important advantages of thermal cameras for homeland security applications: they don’t require any support infrastructure, they provide true 24/7 operational imaging and they act as force multiplication assets, dramatically improving operational response and efficiency.
Support infrastructure. The costs involved in the design, installation, operation and upkeep of a support infrastructure of lighting towers and illuminators quickly outstrips the acquisition cost of a network of thermal security cameras. Because they are not dependant on any visible light, thermal security cameras do not need auxiliary lighting to work, so they can provide effective virtual perimeters for a fraction of the cost of visible-light imagers.
Conventional CCTV cameras -- even ones purporting to be low-light -- need an outside source of illumination to create an image after the sun goes down, leaving them with both economic and tactical limitations.
Their main tactical limitation is that they cannot generate images of intruders or targets beyond the range of their illumination source. This typically limits their effectiveness to a few hundred feet, when a tactical situation might require miles of range. And, this leaves borders and facilities under-secured after sundown.
24/7 video security coverage. Thermal security cameras let people see what their eyes cannot: invisible heat radiation emitted by all objects regardless of lighting conditions. Thermal cameras detect the minute temperature differences between objects and turn them into video that displays on almost any TV monitor.
Because they see heat -- not light -- thermal cameras are effective law enforcement tools in any environment. They can easily detect intruders and other potential hazards in any weather condition, as well as all day and all night.
Cameras that create images based on visible light, like conventional CCTV and illuminated cameras, have the advantage of creating images that are familiar and easy to interpret. Unfortunately, the ability of a given detector -- be it in an eyeball or a camera -- to create these images relates directly to the amount of light available.
At night, for instance, when there is not much visible light, a traditional camera relies on starlight, moonlight and artificial light to help see. If there isn’t enough light, we cannot see anything.
Another limitation of cameras that create images from reflected visible light is contrast. Just like the human eye, these cameras create better images if the object they are looking for has lots of contrast compared to its background. If it doesn’t, they won’t be able to see it. That’s how camouflage works; it is essentially a way of decreasing the visible contrast between an object and its surroundings.
Thermal cameras do not suffer from these basic limitations. Since they make pictures from heat, having nothing to do with reflected light energy, they see the heat given off by everything under the sun. Everything we encounter in daily life creates heat energy, called a “heat signature,” that thermal cameras can see clearly.
Not only does everything have a heat signature, but these heat signatures create their own contrast, so the thermal energy seen by thermal cameras generally creates a better image at night than during the day. They work just fine during the day -- as long as there is the tiniest bit of temperature contrast between an object and its background -- but they work best at night.
An important tactical distinction to understand is that security operators, law enforcement officers and federal agents are not using thermal cameras to identify suspected criminals and terrorists. They use thermal cameras to detect the presence of people in restricted or suspect areas, assess the tactical situation and respond accordingly.
Because no one can hide their heat, thermal security cameras are the best tools officers and agents can use to know how many intruders they are facing and, consequently, how many officers or agents should respond to meet the threat.
Force multiplier. Thermal security cameras act as a force multiplier, allowing law enforcement and security operators to react more effectively -- responding to threats with the appropriate force and using agency resources more efficiently.
For instance, thermal security cameras have been widely adopted as the imaging technology of choice to answer federal regulations requiring unbroken video surveillance coverage, such as the Nuclear Regulatory Commission’s requirement that nuclear facilities do continuous 24-hour surveillance, observation and monitoring of their perimeter and control areas. They have become an integral part of the Delay, Detect, Respond strategy; their increased detection range gives security forces more time to respond, contain and neutralize adversaries before they can access or damage nuclear materials or facilities.
Picking a Thermal Security Camera
Choosing a thermal security camera can seem complicated at first, but maintaining mission requirements as the primary driver instead of technical attributes can help to simplify things considerably. (It should be noted that the following information will deal in generalities. Exceptions exist, but looking at the broader picture will help to simplify the discussion.)
Thermal security cameras are either cooled or uncooled, referring to whether the infrared detector at the heart of the camera’s sensor needs to be cooled to cryogenic temperatures in order to create an image. Choosing an imager depends largely on the needs of the specific application; each has advantages and weaknesses.
Cooled cameras are more sensitive to small differences in scene temperature than uncooled cameras, meaning they can see smaller objects from farther away, making cooled cameras more suitable for extremely long-range imaging in lowcontrast environments.
However, the cry-coolers used in these cameras have moving parts made to exacting mechanical tolerances that can wear out over time, requiring periodic maintenance as they get older. Often, a cooled imager’s life-limiting part will be the cooler itself or some component within it.
Uncooled thermal cameras -- as the name implies -- do not use cryogenic cooling. The most popular uncooled thermal security cameras use uncooled detectors called Vanadium Oxide (VOx) microbolometers. Uncooled sensors are typically sensitive to LWIR energy. They are manufactured in fewer steps than those used in cooled sensors, use less expensive vacuum packaging, and -- most significantly -- don’t require costly cryocoolers.
Uncooled cameras have fewer moving parts and tend to have much longer service lives than cooled cameras under similar operating conditions, making them well-suited to security applications, which often require continuous camera operations. A cooled camera would require service after one to two years of such operation, while an uncooled camera could run uninterrupted for much longer.
With all of the advantages of uncooled cameras in mind, why use cooled cameras at all? As detection range requirements increase past a few miles, cooled thermal security cameras become more cost-effective because of the lens designs. One of the biggest cost drivers of a long-range uncooled camera system is the lens.
As effective range requirements increase, the lenses for uncooled camera systems become more expensive. It is often cheaper to use a cooled thermal security camera with an equivalent focal length lens. Therefore, short-range to extreme mid-range imaging can cost-effectively benefit from uncooled thermal security cameras, while their cooled counterparts are the best solutions when long-range imaging performance is needed.
Thermal security cameras come in a variety of configurations, including fixed-site cameras and multi-sensor pan/ tilt systems. As with the sensor differences, the different configurations each have their unique plusses and minuses.
Fixed-site cameras watch over defined areas, typically access points and areas of special concern or vulnerability.
Because of their increased range capability compared to visible-light cameras, a handful of fixed-site thermal security cameras can cover an area that would otherwise require dozens of CCTV cameras.
Pan/tilt cameras -- whether singlesensor thermal security cameras or multi-sensor systems with thermal and EMCCD low-light cameras -- are used to cover wider areas. Because panand- tilt thermal security cameras have longer lenses that are more sensitive to being buffeted by the wind, they often include some type of stabilization capability as well: either physical stabilization of the pan/tilt mechanism done with internal gyroscopes, or electronic image stabilization.
High-performance systems also will include laser rangefinder and digital magnetic compass payloads that allow the sensor package to precisely geo-locate anything in its field of view.
The answer to the question, “Which one is right for me?” is usually not a matter of either/or. Integrating fixedsite and pan-and-tilt camera systems creates a synergy that offers much greater security than either could provide alone.
Often, fixed site cameras and pan/tilt cameras are networked together with a video analytics package so intruders detected by a shorter range fixed-site camera installed along a perimeter can be investigated more thoroughly with the longer range pan/tilt camera installed in a more central location.
Because of their high-contrast video output, thermal security cameras work very well with video analytics, providing more reliable alarming with fewer false reports than visible-light cameras, even during the day.
Into the Future
Thermal security cameras are not quite ubiquitous throughout the breadth of homeland security applications, but -- thanks to recent reductions in price and increases in capability -- they’re getting there. Fixed-site, network-ready thermal cameras that cost more than $30,000 only a few years ago are now available for less than $5,000.
As the cost of thermal security technology continues to decline, and cameras get smaller, applications for this technology will continue to grow. Today, military UAVs carrying thermal cameras smaller than a cell phone are in constant use in Southwest Asia; these could easily be used to patrol national borders and extended facility perimeters.
One of the growing applications for thermal security cameras are as handheld devices, giving agents and other security professionals on patrol the capability to carry this bleeding-edge technology with them wherever they go. Handheld thermal cameras designed for security and law enforcement roles are currently on the market for less than $5,000, and vehicle-mounted thermal cameras go for less than half that price.
Thermal security cameras offer the best 24/7 imaging range performance available. They are easily networked and work better with video analytics packages than other low-light imaging solutions. They come in a variety of technologies and configurations, providing a solution for any high-security installation or border. Finally, they are inexpensive to operate, they do not require auxiliary lighting infrastructure, and their acquisition costs are projected to continue their downward trend, creating the “perfect storm” of affordability and return on investment.
Taking into account their imaging performance, flexibility, networkability, and cost, thermal security cameras provide the best technology available for 24-hour video surveillance of the high-security facilities and borders patrolled by the Department of Homeland Security.
This article originally appeared in the July 2010 issue of Security Today.