Infrared (IR) cameras can convert IR radiation, invisible to the human eye, into a visual image that depicts the thermal variation across an object or scene. IR is emitted by all objects at temperatures above absolute zero, and the amount of radiation increases with temperature. The main components are the lens focusing IR onto a detector, plus electronics and software for processing and displaying the image. The IR camera is a focal plane array of micrometre size pixels made of materials sensitive to IR wavelengths. It allows one to make non-contact measurements of an object´s temperature in which IR cameras detect the electromagnetic radiation in the range 0.9 to 14 µm and produce images of that radiation. Thermal cameras find applications in night vision, surveillance, military & medical purposes, and more.