Thermal imaging works by translating heat into visible light for the purpose of analyzing a particular object or scene. The resulting image is known as a thermogram, and it is then studied through a process known as thermography.
Thermal cameras are used in many fields today. Firefighters often use them to see through smoke, locate people, and determine the hotspots of a fire. Law enforcement may use it for surveillance, locating suspects, investigating crime scenes, and use in search and rescue operations. Maintenance workers may use it to locate overheating joints and parts in order to eliminate potential failures, and construction workers can use it to determine where heat leaks out of a building to improve heating and cooling efficiency.
When shopping for a thermal camera, there are different features to consider. On the low end, you may only get one fixed crosshair to measure temperature with. Higher-end cameras may feature multiple crosshairs that can be moved around to compare different points that the camera is looking at, including the high, low, and average temperatures of the points selected.
Some may also include different color palettes which each excel at different functions. Other cameras may even feature a function to only highlight points at or above a specified temperature. Finally, more expensive cameras will also typically feature a higher-resolution lens.