Surveillance cameras greatly extend our ability to remotely monitor the outdoor movements of people, animals and machinery. But what happens when an area is enveloped in heavy rain, fog, smoke or total darkness? That’s when it’s time for thermal cameras capable of “seeing” objects based on the heat they radiate.
Thermal cameras work by capturing levels of infrared light that’s invisible to the human eye. This light can be felt as heat. Hotter objects produce more infrared radiation that is captured by camera sensors. This enables them to be used for detection purposes 24/7. They’re effective in bright sunlight parking lots or along pitch-dark perimeters. The cameras make it difficult for people to hide in and around trees and bushes. And false alarms are reduced as the cameras detect moving sources of heat, not blowing trash.
Thermal cameras are ideal for use in protecting large perimeters around airports, campuses, utilities, transportation hubs and government facilities ¬– virtually anyplace traditional vision cameras are less effective.
We’ve all seen monochromatic thermal images lacking the detail provided byvisual security cameras. Thermal cameras may detect differences of temperature as small as 1/20th of a degree and display images using more than 16,000 shades of gray. That’s far more detailed than the human eye can discern.
Older cameras tended to lump together areas close in temperature to produce those muddy, non-detailed images. Newer image processors are better at highlighting subtle heat differences to provide video with much greater contrast and detail. That’s even true during the day when the sun’s energy can create a uniformly hot scene. Some thermal camera sensors detect and display pseudo-color images that reflect differences in temperatures within a camera’s field of view.
Thermal imaging was developed in the 1920s and was initially developed and promoted for military use. By the 1990s, thermal cameras were being used for commercial security. Here are some reasons for their appeal:
- Thermal cameras work well with video analytics to detect intruders over large areas, ignoring movement from small animals, blowing trees, moving clouds and shadows.
- Some cameras include laser range finders, GPSand magnetic compasses allowing them to track movements of thermal images.
- Thermal cameras operate in extreme hot and cold environments.
Cameras are available to integrate with existing IP-based and analog security systems and video management systems. There are also wireless models ideal for installation in remote areas.
Contact usto see if thermal cameras may be right for your organization.
(Chris Krajewski vice president of services for Ojo Technology)