A thermographic camera is similar to an infrared camera in that both form images based on infrared radiation. A thermographic camera differs from an infrared camera in that IR cameras display a monochromatic image which is a response to a single wavelength of light. Thermographic cameras, however, measures changes in temperature and displays images in pseudo-color, with the hottest areas in white, areas of medium temperature in reds and yellows, and the coolest areas in blue.
Types of Thermographic Cameras
There are two types of thermographic cameras: those with cooled infrared image detectors and those with uncooled detectors. Cameras with cooled detectors are cryogenically cooled and are housed in a vacuum-sealed case. They need to be cooled due to the semiconductor materials used inside the camera for photodetection. Uncooled cameras use a sensor maintained at an ambient temperature and measures the change between this sensor and heat produced by infrared radiation to produce a picture. Cooled infrared cameras produce a superior image when compared to uncooled cameras but they are more expensive in terms of cost and operation.
Thermal Imaging Cameras
A thermal imaging camera is a specific type of thermographic camera used primarily for firefighting because of its ability to see through smoke and darkness. While relatively expensive at the time of writing, they are credited with saving lives in worst case scenarios. Besides seeing through smoke, they have aided in situations involving low level spontaneous combustion. The majority of thermal imaging cameras are handheld but they also are available in helmet mounted versions.
Recently, thermal imaging cameras are being used for surveillance purposes, including monitoring plant operations, detecting leaks, ruptures or other areas of concern. Cameras are used to not only detect traditional targets, such as human beings and vehicles, but also untraditional targets, such as liquids and gases.