How Do Thermal Imaging Systems Work?

Thermal imaging systems are special instruments that create images of heat instead of light. The higher the temperature of an object is, the more infrared radiation is emitted back to the camera. The camera is able to detect this radiation similar to how a normal camera detects levels of light. In cases where a thermal imaging system is used, light level is irrelevant because the camera only detects black body radiation.

The Basics of Thermal Imaging Systems

The process begins when a special lens focuses solely on heat that is emitted from any objects within its detection range. A phased array made up of infrared parts is used to scan the light that is portrayed by the heat source into the camera. The result of the scan is a special temperature image known as a thermogram.

Once the process is completed within a matter of seconds, the thermogram is transferred to a special signal processing device which processes the information and turns it into a readable display. The thousands of impulses from the thermal elements are the main components of the readable image.

Types of Thermal Imaging Systems

There are two basic types of thermal imaging systems currently in use today:

Cryogenically-Cooled Systems- These types of thermal imaging systems are more expensive than un-cooled systems but tend to break more frequently as well. In a cryogenically-cooled systems, the elements are contained inside a compartment that keeps them at a temperature below freezing (32 degrees). The advantage of using these types of systems is that the units can detect a change in temperature that is less than one quarter of a degree (0.2) at a range of up to 1000 feet away from the object.

Un-Cooled Systems- This is the most common type of thermal imaging system currently available. The elements are kept at room temperature and the system is available for immediate use right when it's turned on. While the pictures aren't as accurate, un-cooled systems are much cheaper and require less maintenance.

Current Uses for Thermal Imaging Systems

Thermal imaging is used in a wide variety of business sectors:

  • Military - Thermal imaging is used by the military to detect threats from a distance and when visibility is at zero.
  • Law Enforcement - Law enforcement agencies use these systems to detect what type of threats they face from a distance. For law enforcement agencies, these devices are normally hand held, mounted inside a vehicle or on the top of a weapon.
  • Industrial Uses - Thermal imaging systems are used by a variety of industrial businesses. Construction companies can inspect air quality within a building or find flaws in window and door jams by inspecting the area for heat sources. Manufacturers of mechanical parts can measure the performance of similar parts by detecting the amount of heat that is generated by both items.
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