What does a thermal image camera detect?

A thermal imaging camera detects infrared radiation , so option A is correct. This question is deliberately testing the difference between what the camera detects and what the displayed image may represent. The camera’s sensor detects infrared energy emitted from the surface of an object. The instrument then converts that infrared signal into a thermal image and may calculate an apparent temperature using assumptions such as emissivity, reflected temperature, distance, and atmospheric conditions. Option B is therefore not technically precise. Temperature is inferred or calculated from detected infrared radiation; it is not what the camera directly detects. Option C is also incorrect because emissivity is a material/surface property that affects how efficiently an object emits infrared energy. It must often be entered or compensated for during thermographic analysis, but the camera does not “detect emissivity” as the primary measured quantity. In CRL Asset Condition Management, this distinction matters because incorrect interpretation of thermography can lead to wrong maintenance decisions. NASA explains that infrared cameras allow us to see infrared waves emitted from warm objects, which directly supports option A.