Q+A CENTER
Latest question:
How do you think the new GigE standards will influence the machine vision industry?
Respond or ask your question now!
Advanced Imaging Magazine
Most Read
Most E-mailed
Print Article
From Home Security to Homeland Security
Day or night, thermal security cameras keep watch on the borders and in your neighborhoods
By David Lee
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 and are manufactured in fewer steps than those used in cooled sensors. They also 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.
Configurations
Thermal security cameras come in a variety of configurations, including fixed-site cameras, multi-sensor pan/tilt systems, and inexpensive handheld cameras. As with the sensor differences just discussed, the different configurations each have their unique plusses and minuses.
Fixed-site cameras are obviously used to 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 require dozens of CCTV cameras.
Pan/tilt cameras, whether single sensor thermal security cameras or multi-sensor systems with thermal and EMCCD lowlight cameras, are used to cover wider areas. Because pan/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 will also include laser rangefinder and digital magnetic compass payloads that allow the sensor package to precisely geo-locate anything in its field of view.
