For temperature measurement calibration of infrared cameras, what are used as reference targets?

• A. Blackbodies
• B. Thermocouples
• C. Mirrors
• D. Color targets

Answer: (A)

When calibrating an infrared camera, you need a stable, well-understood radiative source whose emitted infrared energy matches a known temperature. A blackbody provides exactly that: a surface that absorbs nearly all incident radiation and emits a predictable amount of infrared energy according to Planck’s law, with emissivity close to one. By using a blackbody (often in a cavity design) at known temperatures, you can map the camera’s radiance readings to actual temperatures, creating an accurate radiometric calibration across the temperature range of interest. Thermocouples measure temperature but don’t emit infrared radiation as a reference source, so they don’t provide the necessary radiance target. Mirrors merely reflect the surroundings and don’t supply a controlled infrared emission. Color targets are used for visible-light testing or aesthetic references and don’t yield the stable, known infrared radiance needed for this calibration.