Thermal Imaging

Thermal Imaging

A thermal camera detects and records the infrared radiation (heat signatures) of objects. The information is converted to an electronic image that displays the object’s apparent surface temperature. The image can also show temperature differences on the object, depending on its size, shape, and emissivity. Read more metal

All objects emit infrared energy. The energy is reflected off the surface of the object, transmitted through it, or absorbed by its materials. The result is an electronic signal that is recorded by the infrared detector. The detector signals are converted to a video or still image by an optical system that focuses the infrared energy onto a special sensor chip (sensor array). The camera is usually powered by a battery and operates similar to a camcorder.

The infrared detector chip in a thermal camera is made from materials that are highly transparent to the IR spectral range and is arranged with thousands of pixels grouped into rows and columns, similar to a digital camera. The sensor array is then connected to a display screen that shows the temperature data in real-time.

The Power of Infrared: How Thermal Imaging Is Changing Industries

There are a wide variety of applications for thermal imaging, including security, search and rescue operations, electrical inspections, and HVAC inspections. It is especially useful for finding deterioration in components prior to failure.

In the past, inexpensive cameras with CCD and CMOS sensors have been used for infrared thermometry (pyrometry) by applying color contours to images to distinguish temperatures. However, this type of pyrometry is limited by the noise characteristics of the imager and requires the use of external filters to obtain good results. Specialized thermal cameras are available with Focal Plane Arrays (FPA) that respond to longer wavelengths, such as InSb, InGaAs, or HgCdTe. Some models require cryogenic cooling to achieve good performance.