What's Out There?
Thermal imaging provides boost for existing security solutions
- By Mike Studer
- Sep 01, 2006
CAN you think of a building, structure or facility that would not benefit from heightened security? Probably not. In response to increasing criminal activity and terrorism, fail-proof security is a must, whether protecting a local convenience store or securing a nuclear power plant. This is a high stakes world. Civic infrastructure, communities and public works continue to be vulnerable.
In response to increasing criminal activity and terrorism, fail-proof security is a must, whether protecting a local convenience store or securing a nuclear power plant. This is a high stakes world. Civic infrastructure, communities and public works continue to be vulnerable.
Security systems have evolved significantly over the past few years, just as the approach to security and safety have matured over time. Our society is now proactively designing security solutions in an effort to stay several steps ahead of threats, voiced and unvoiced.
Presently, most facility video surveillance equipment is designed to be effective during daylight hours. Darkness severely degrades the performance capabilities of such video surveillance systems. For this reason, many of the organizations using this equipment rely on security lighting systems for nighttime surveillance. And while security lighting has met with some success, purchasing and installing an adequate amount of lighting can be expensive, obtrusive to surrounding residential areas or even impractical.
Another common approach to nighttime surveillance is to integrate conventional surveillance cameras with motion detectors and some type of night vision. However, these systems alone do not have the advanced optics to provide security officials with the viewing range required in many scenarios. And in some areas -- coastlines, borders and railways, to name a few -- the technologies are not able to detect criminal activity in darkness or in adverse weather conditions such as fog or rain, that also compromise standard vision capabilities.
For all of these reasons, thermal imaging stands out to an increasing number of security managers. In order to understand exactly why thermal imaging is emerging as the top choice for security system installations, it helps to review the features of some commonly used types of surveillance technology. The four most common types are: Thermal imaging, day TV with lights, CCTV with infrared illuminations and image intensification.
While traditional cameras require ambient lighting to be effective, thermal imaging detects the self-emitted heat of an object and therefore requires no visible light to produce images. The images produced are typically in black and white -- though some thermal imaging cameras are beginning to provide color images -- with hotter objects appearing as white and cooler images appearing as dark, or the user may reverse this color assignment if desired. Thermal imaging essentially makes people, running vehicles and other heat-emitting objects appear to "glow" white against the darker, cooler surroundings.
While it may be possible to "trick" other technologies by using camouflage to blend into the background, it is impossible for security teams to overlook glowing intruders, even when they try to blend in with the background. Because thermal cameras detect heat -- rather than rely on light -- to produce images, enhanced security is assured 24 hours a day, seven days a week, in darkness and in light, even where a traditional camera and improved lighting may fail.
Unlike other camera solutions, thermal imagers remain effective over long distances. The imagers can identify heat signatures from distances up to a mile away. Not only are they able to see over long distances, but they also are able to see through smoke and fog. And because thermal imagers work night or day, rain, shine or fog, the cameras serve as a proactive, rather than a reactive, security tool. Detecting suspicious activity can actually prevent an intrusion whereas traditional cameras serve as great tools for reporting the breach after a crime has been committed.
Thermal imaging is a proven technology that has had success in a variety of security scenarios. It provides vision at night in situations where lighting is undesired, but 24/7 surveillance is a requirement. Thermal imaging cameras can conduct surveillance over waterways, lakes and ports where water and lighting options are impractical. Thermal imagers enable surveillance, despite inclement weather conditions which would challenge other technologies. Additionally, the cameras provide low maintenance requirements for users based in remote or difficult locations along with low-cost operation over the life of the product.
For these reasons, thermal imaging cameras are increasingly becoming a welcome addition to the integrated security solution. Security and surveillance professionals recognize that nighttime breaches of security are a significant threat and the security solutions most widely used are inadequate for viewing in darkness or conditions in which vision is compromised. With thermal imaging technology, security professionals can detect potential intruders at long ranges, identify a threat and proactively respond to it.
Day TV with Lighting
Day television with lighting supplies sufficient light to enable traditional cameras to watch for intrusion. While the cost of each individual camera is relatively low, the quantity of cameras and the number of lights that must be installed to adequately monitor a facility can be substantial.
The light produced by these cameras can draw unwanted attention, particularly if the facility is located in a remote or residential area or along a coastline where lights actually serve as beacons. If some areas are lit while others are not, it is easy for intruders to pinpoint vulnerable areas and then breach the facility's security.
For parking lots and other frequently visited, controlled areas, electric lighting is considered imperative. However, lights are indiscriminate -- they offer the same amount of illumination to intruders as they do to security professionals. Furthermore, intruders know exactly where security is expected to be at its highest, and they likely will avoid those areas, thus making day TV and lighting ineffective for many types of passive facility security.
CCTV with Infrared Illumination
If day TV with lighting is determined to be an ineffective means of securing a facility, security professionals must seek out a more technologically advanced solution. Infrared illumination cameras, used in CCTV systems worldwide, are often a solutions that professionals consider. Infrared cameras have viewing capability in the 0.4 to 1.1 um wavelength band, but usually require enhanced illumination to be able to detect images -- meaning they need some illumination, which they get from Infrared sensors, to work in semi-darkness. Several different types of technology fall into the Infrared illumination category, including diodes, IR lamps and lasers.
Diodes are widely available, small, inexpensive and require a low level of power. However, like day TV, diodes are most effective only when used over short distances and significantly degrade in certain types of weather.
IR lamp technology provides illumination over increased distances, but it is expensive, significantly larger than diodes, requires high levels of amperage and also is degraded by weather. Laser technology offers the greatest illumination distance of the three types and can see through most weather conditions. Nevertheless, lasers are very large, expensive and require a significant source of power to function properly. In addition, lasers have a very narrow field of view, and misuse can lead to serious eye damage. For these reasons, lasers traditionally have been limited to use by highly-trained military personnel.
Regardless of the type of illumination, the cameras measure the contrast in reflected light and reflected near IR. Reflected energy depends on the color and sheen of objects in each respected field of view. An individual attempting to be covert and avoid the camera's watchful eye can simply wear dark colors and avoid the use of shiny objects to limit the effectiveness of the cameras.
As with all types of illumination, the performance of a CCTV with IR largely depends on range. The cameras function best at close range -- about 75 feet. At that range, the infrared illumination can take effect. CCTV with infrared illumination or day TV systems can require enough lights or illuminators to brighten an entire coastline in order to see objects just 1,000 feet away -- a solution that, even if it were technically possible, would still be cost prohibitive and nearly impossible to maintain.
Image intensification is another sophisticated type of illumination -- the most widely known of the night vision system -- which works by amplifying the ambient light of a scene. The technology requires a natural or artificial illumination source to be effective. Image intensification results in grainy, green images, as often seen on news shows and in war coverage.
The most common problem with image intensifiers is their dependency on stray light sources. Consider this combination: cloudy skies and a power outage, perhaps caused by a hurricane. The image intensification technology is rendered useless in conditions of complete darkness, as would be the case in a dark building.
Car headlights, powerful flashlights or other sources of bright light can handicap the devices easily. Susceptibility to this blooming effect makes these cameras effective only on a marginal basis. Intruders with any knowledge of the systems can use bright lights to cause a blooming effect that would temporarily shield them from the camera's view. Trespassers also can create a blooming effect to serve as a decoy or distraction and allow additional intruders to infiltrate a facility in a separate location.
Back to the Future
There are many technologies available to security professionals. As new security threats are uncovered each day, and as such threats grow more and more sophisticated, security managers need to do all that they can to prevent invasion, sabotage and attack.
Technological advances in thermal imaging technology -- such as the use of color or increased range -- also are making its use as part of an overall security solution increasingly ubiquitous. As the adoption of thermal imaging technology increases, it will continue to be integrated to work with a host of security applications, including motion detectors, access control systems and specialized software. These advances, including improved clarity, also will make the technology even more effective for security purposes.
By adding thermal imaging to an already well-developed security system, security managers will be able to protect facilities and assets, rather than just react to an intrusion, theft or worse. This increased level of security is beneficial to every facility -- big or small.
This article originally appeared in the September 2006 issue of Security Products, pgs. 53-55.