The FLIR system primarily detects targets by sensing which type of radiation?

• A. Infrared radiation
• B. Visible light
• C. Ultraviolet radiation
• D. Microwave radiation

Answer: (A)

Infrared radiation. FLIR systems are thermal imaging devices that detect heat emitted by objects in the infrared part of the spectrum, not visible light. Any object above absolute zero emits infrared energy, and the amount and distribution of that energy depend on temperature. The sensor converts this infrared energy into an electrical signal and displays it as an image, where brighter areas typically indicate higher temperatures. This allows detection in darkness, through smoke, or in low-contrast lighting. It’s different from visible-light, UV, or microwave systems, which rely on other parts of the spectrum for detection. Common FLIR bands include long-wave infrared (roughly 8–14 micrometers) and, in some systems, mid-wave infrared (about 3–5 micrometers).