Thermal network cameras
Thermal network cameras create images based on heat that radiates from all objects. Images are generally produced in black and white but can be artificially colored to make it easier to distinguish different shades.
Thermal images are best when there are great temperature differences in a scene; the hotter an object, the brighter it is in a thermal image.
Thermal cameras are ideal for detecting people, objects and incidents in shadows, complete darkness or in other challenging conditions such as smoke and dust. The cameras are used primarily to detect suspicious activities as thermal images do not enable reliable identification. They, therefore, complement and support conventional network cameras in a surveillance installation.
Thermal cameras can be used for perimeter or area protection, providing a powerful and cost-effective alternative to radio frequency intruder detection, electrified fences and flood lights. In the dark, they provide discreet surveillance since there is no need for artificial light. In public areas, thermal cameras can help secure dangerous or off-limit areas such as tunnels, railway tracks and bridges.
Indoor uses include building security and emergency management, enabling humans to be detected inside a building, whether after business hours or during emergencies such as a fire. Thermal cameras are often used in high security buildings and areas such as nuclear power plants, prisons, airports, pipelines and sensitive railway sections.
A thermal camera requires special optics since regular glass will block the thermal radiation. Most thermal camera lenses are made using germanium, which enables infrared light and thermal radiation to pass through. How much or how far away a thermal camera can “see” or detect depends on the lens.
A wide-angle lens enables a thermal camera to have a wider field of view, but a shorter detection range than a telephoto lens, which provides a longer detection range with a narrower field of view.
A thermal camera’s sensitivity to infrared radiation is expressed as its NETD value (Noise Equivalent Temperature Difference). The lower the NETD value, the better the sensitivity to infrared radiation.