Thermal imaging cameras operating in the medium mid-wavelength spectrum employ a different technology that does require the chip to be cooled to increase the signal-to-noise ratio.
Purpose and Resolution
Thermal imaging cameras are primarily used in applications where detection, not identification, of an intruder is the goal. This is illustrated in the photos below, where the thermal pattern clearly represents a human; however, the lack of facial or body structure in the image precludes any further analysis leading to identification of a specific individual. While resolutions of 4 CIF and higher are available, most cameras deployed today for security applications have typical resolutions in the CIF range.
Coupled with the fact that the image is in black-and-white, the resulting digital image file is much smaller than security practitioners are accustomed to handling. As a result, the bandwidth requirements for a thermal imaging camera are miniscule by current security standards.
Other Features and Technological Developments
Current thermal imaging product offerings by FLIR and others offer many features that the industry has demanded of visible light cameras. Power over Ethernet (PoE)-enabled, IP-addressable devices are appearing on many of the newer models, allowing ease of integration of similarly equipped visible light systems.
Thermal imaging systems are also excellent platforms for video analytics. With visible light cameras, video analytic applications have to deal with a broad range of slight color variations — both in the background and the object to be detected. With a thermal image, the object of interest normally displays a high level of contrast to the background based on the temperature differential, making it relatively straightforward for video analytic detection.
Perhaps the most significant development is the price points on some of the newer models that might be appropriate for short-range facility and campus applications. Uncooled thermal imaging cameras are now available with a manufacturer’s suggested retail price of $3,000. While somewhat more expensive than a suitable visible light camera, these devices provide an ability to covertly monitor for movement without the expense and environmental considerations associated with providing lighting for a visible light system.
Borders and ports have represented surveillance and detection applications that were out of reach prior to the availability of thermal imaging CCTV systems. Given the limitations of human detection and the expense associated with providing lighting for a large-scale visible light camera system, securing large perimeters was essentially unaffordable. These devices provide the ability to view large fields of view at ranges that would make it nearly impossible for the human eye to detect even large-scale movement.
Some of the cooled medium wavelength devices are often coupled with a ground-based radar system. The radar system detects movement; the thermal imaging camera then focuses on that location to provide the security monitoring personnel a visible (thermal) picture of the detected object. These devices, often priced well above $50,000, address the previously unaddressable problems efficiently, and considering the alternatives, cost-effectively.
However, the bulk of the CCTV cameras implemented address the security concerns of more modestly sized facilities, campuses, high-end residential estates and infrastructure sites where the challenge is not one of physical scale but of cost-effectively providing a video record of site activities. As the price of thermal imaging systems continue to decline, and video detection — not identification — is an acceptable intermediate outcome, these systems will see expanded use where visible lighting is either not an option technically or is excluded prior as a consideration.
Making a Choice