Criminals are a varied bunch. Their intelligence levels cover a wide spectrum, but, regardless of their IQ, most criminals will not try to break into the average facility in broad daylight. The night offers more cover, both for the infiltration and the escape. The thing is, most facility video surveillance equipment is designed to be effective primarily during the daytime. Extreme darkness can severely degrade the performance capabilities of industrial video surveillance systems.
Many security consultants believe the best way to combat the darkness is with security lighting systems. While security lighting can be effective, purchasing and installing an adequate amount of security lighting can be expensive. In addition, some facilities are located in areas where security lighting is obtrusive or impractical. Such locations include residential areas. While many different techniques and technologies have been tried as solutions for nighttime surveillance (ie; infrared lighting, standard lighting, intensified imaging), the benefits of thermal imaging are attracting more and more security managers. To understand why thermal imaging is becoming so popular, it helps to review the attributes of several of today's popular forms of surveillance technology. The most common types are as follows:
- Thermal Imaging
- Day/Night Cameras (Dual-Chip Technology)
- CCTV with Infrared Illumination
- Image Intensification
Thermal imaging detects the self-emitted heat of objects. As such, thermal imaging cameras need no visible light to produce an image. Typically, the image produced is black and white, where the hotter objects are whiter and the cooler objects are darker. Thermal imaging essentially makes people and running vehicles glow white against the darker, cooler background. When you view a display screen, it is virtually impossible to miss the glowing intruders, and they cannot use camouflage to blend in with the background.
Unlike other security camera solutions, thermal imagers are extremely effective for long distances, identifying objects with a heat signature from a few feet away to a few thousand feet away, and they "see" objects through smoke. In addition, because they detect objects based on differences in temperature, they can be effective both day and night. With the proper, interactive triggers and/or video motion detection systems, thermal cameras have the advantage over other styles of specialized imaging systems in extreme lower light levels and total darkness. Thermal imaging has proven to be a successful solution for a host of security scenarios, including the following:
- providing vision at night where lighting is undesired and 24x7 surveillance is needed
- conducting surveillance over waterways, lakes and ports where water and lighting options are impractical
- enabling surveillance through weather conditions where other technologies will be challenged
- providing low maintenance requirements for facilities based in remote or difficult locations
- offering low-cost operation over the life of the product
Thermal imaging is slowly but surely emerging as a common addition to integrated security packages. Companies are able to rely on thermal imaging for specific applications where no other technology has been able to perform as well in the past.
There are several situations within security applications where standard or specialized lighting techniques will not work. With thermal imaging, security professionals can detect intruders at long ranges with unprecedented clarity and under extreme lighting conditions.
Day/night cameras use either dual-chip or dual-scan technology, allowing for color images under normal lighting and black-and-white images under lower or nighttime lighting. The cost of individual cameras is not high, but in some situations, large numbers of cameras and multiple lights may have to be installed to cover a facility adequately. This can drive up the cost of the solution. In addition, such increased lighting may call attention to a facility, especially if the location is remote or on a coastline, where lights become a beacon.
Often, electric lighting is considered imperative for frequently visited, controlled areas. But lights are indiscriminate, offering the same level of illumination to intruders that they offer to security professionals. This can make lighting and day/night cameras ineffective for some types of facility security.
CCTV Systems with Infrared Illumination
Infrared sensitive cameras (most black-and-white CCD units) are used in CCTV systems all over the world. This type of specialized lighting is the first of the more sophisticated night viewing solutions. Infrared-sensitive cameras require illumination, either visible or IR, to work in semi or complete darkness, and they get this illumination with IR lamps. There are several types of infrared illuminators available. Each has its place and purpose. Varieties include LED array, halogen and laser.
LED array technology is small, inexpensive, uses a low level of power and is widely available. The first drawback is that it illuminates only very short distances (15 to 300 feet average) and can be degraded significantly by certain types of weather.
IR lamp technology offers increased illumination distance, but can be expensive, is physically large, uses high levels of power and is degraded by weather. Halogen technology also requires annual maintenance as the bulbs deteriorate.
Laser technology offers the greatest illumination distance of the three types and sees through most types of weather, but those capabilities make laser solutions expensive. In addition to being cost prohibitive, laser technology is very large, uses extensive amounts of power, has a narrow field of illumination, is unsafe to the eye and is available primarily for military applications. Regardless of the type of illumination, each of these cameras measures the contrast in reflected light and reflected near IR. Reflected energy depends on the color and sheen of objects in the field of view. As discussed, for all types of illumination, range is a key factor in the performance of a camera using IR illumination. For CCTV applications with infrared illumination, lighting an entire coastline with lights or illuminators to see even 1,000 feet is not cost effective and would most likely prove to be prohibitively expensive and logistically difficult to maintain.
Image intensification, another sophisticated type of illumination, works by amplifying the ambient light of a scene (at the face of the imager or CCD) and, therefore, must have some minimal source of light to be effective. Image intensification is one of the most widely known of the night vision systems. The three major drawbacks of such cameras are 1) upfront cost of the camera-ranging from $3,500 to $7,000 each; 2) long-term maintenance-average life expectancy of the intensifier/CCD setup is two to four years; 3) these cameras require at least starlight to full moon to operate, and such lighting must be in the visible range. IR lighting will not work.
The Future of Thermal Imaging in Security
Thermal imaging's popularity among security managers continues to increase. As the volume of installed systems grows, price points are likely to decrease. This bodes well for facilities of all types, but it is particularly good news for facilities located in areas where other types of security cameras and lighting systems have been impractical or ineffective.
Technological advances in thermal imaging technology also are likely to increase its use as part of overall security solutions. As the adoption of thermal imaging technology increases, it will continue to be integrated to work with a host of security applications, including video motion detection, access control systems and specialized software. Also, its ability to see over greater distances will increase in the years to come, making the technology even more effective for wide range security applications.
Ultimately, this increased level of security is beneficial to everyone, except, of course, a criminal.
John Love is the director of security and homeland security market development for Raytheon Infrared. Mr. Love has more than 25 years of experience with thermal imaging products and markets. He has been with Raytheon and Texas Instruments since 1978 in a variety of technical, product development, sales and account management roles.