Working Function of Infrared CCTV Cameras

Most Infrared Security System will be able to capture clean images during the day – which is exactly what you want. The overall effectiveness of a camera is marred if you aren’t also fully protected at night-time. Night-time security is vital to have because criminals will often choose to act under the cover of darkness. This is why infrared CCTV is a great all-round surveillance choice – it gets good picture coverage no matter the time of day or night. As CCTV becomes more commonly used, the systems become more sophisticated, infrared CCTV for example, is now an affordable way of protecting a low-light area. Infrared closed-circuit television cameras make this a reality, effectively monitoring the darkness for your surveillance system.

Thermal Imaging - The process used by infrared CCTV cameras for night-vision is known as thermal imaging. People and objects constantly emit a level of heat referred to as thermal energy. Thermal energy resides in the electromagnetic spectrum which in turn occupies the top of the infrared light spectrum. Thermal energy is invisible to the naked eye because it is emitted from a source, as opposed to being reflected by light. Infrared CCTV cameras use thermal imaging to capture various levels of thermal energy and convert it to a light-based image that is visible to the human eye. This process of revealing the invisible occurs over several steps:

A. Infrared Lens - The specially designed lens of an infrared camera is used to focus the levels of invisible infrared radiation within its view.

B. Thermogram - Infrared detectors review the radiation focused by the lens and proceed to create a temperature map known as a "thermogram." The completed thermogram is then translated into a series of electric impulses.

C. Signal-Processing - Once converted into electric impulses, the thermogram is sent to a chip on the camera or server known as the signal-processing unit. This unit rebuilds the electric impulses as usable data.

D. Display - Once translated, the usable data is sent to the display, where it is appears as a graphic rendition of the contrasting heat emissions that were originally captured. These images exist in the visible spectrum, allowing the human eye to see the subject via its own thermal energy.

Cooled or Uncooled - Most infrared cameras fall into the "uncooled" category, meaning that camera is not equipped with any kind of onboard cooling mechanism. Cryogenically cooled infrared cameras, on the other hand, are higher-end devices featuring a sophisticated cooling device. Although this variety of camera is considerably more expensive than the more common uncooled versions, it provides the camera with an extremely high level of sensitivity to thermal energy variations. This means that cryogenically cooled infrared CCTV cameras can receive a much finer range of information, resulting in images with much more detail and depth.

In the Dark - Because infrared CCTV cameras draw all of their images from a person or object's level of infrared radiation, their performance and image quality is in no way affected by light. Whether covering an area engulfed in darkness or filled with blindingly bright lights and flares, an infrared CCTV camera will always perform at the same level.

Infrared CCTV Cameras needs a light to be able to capture images, however, this light is not visible to the human eye. The camera works in conjunction with LEDs (light emitting diodes) which provide the camera’s light source. Once light levels drop below a certain level, the camera will illuminate the area with its own infrared LEDs. These LED’s are either built into the infrared camera, placed separately, or both; more LED emitters means more space illuminated and therefore a larger visible area at night. Various types of emitters are available and they operate at different frequencies which may cause them to emit a slight red/orange glow which is visible - the more you pay for high-quality emitters, the less obvious this glow will be. It is possible to buy emitters that operate at a frequency invisible to the human eye, but expect to pay more for the better technology.The images the CCTV captures are saved either to VHS or more commonly a hard drive, which you will then be able to view.