While building IRWorks, one question kept coming up: why does the same IRT image read 98°C in the camera maker's own software and 96°C in ours? Behind that question sits an entire temperature-inversion pipeline that most users never see.
What an IR camera actually records is not temperature, but the radiant intensity hitting the sensor (a count value). Converting that count into a displayed temperature requires radiometric calibration, ambient-radiation correction, atmospheric attenuation, emissivity correction, reflected-temperature correction and distance correction, among others.
Different vendor software does not share the same default assumptions. The most common differences: default emissivity (0.95 vs 1.0), default ambient temperature (20°C vs the camera's self-measured ambient at capture time), and defaults for humidity and distance. Those differences show up as the familiar 2-3°C reading gap.
IRWorks exposes these parameters explicitly in the UI. The user can see which assumptions were applied to each image and revise them. For compliance-testing scenarios, reports automatically include a snapshot of the exact parameters used, so a third party can reproduce the analysis.
There is no absolutely correct temperature inversion — only the question of whether your assumptions are reasonable and auditable. We chose to put that in plain sight.