Absolute temperature measurement accuracy
Most infrared cameras with 8-14 μm spectral response are specified with an accuracy of +/- 2 °C or 2 % of the reading based on deployments in industrial environments in a wide variety of ambient conditions from 32 °F to 122 °F.
Many infrared cameras with microbolometer sensors are promoted today with accuracies of +/- 0.5 °C or better. These accuracies cannot be achieved without the use of a black body reference source. The source needs to be stable, have high emissivity and positioned in the scene proximate to the subject to be scanned.
Our BR 20AR ambient referencing source can be combined with our PI 400i T010. The black body is equipped with a 16 bit digital temperature sensor with +/- 0.1 °C accuracy. By integrating this highly accurate reference signal to our PIX Connect software, we can reduce camera uncertainties resulting from device adjustment, ambient temperature drift and short term stability down to a system accuracy of +/- 0.5 °C with a confidence interval of 95 %.
The use of a reference source and 0.5 °C measurement accuracy are recommended in the latest FDA guidance issued in April 2020 and the Optris PI400i and BR20 comply with these recommendations.
The real ability of an IR camera based screening system to detect subjects with fever lies more in the ability to discern which external face temperatures, as measured at the tear duct/ Medial canthus, are significantly higher than those in a given population exposed to similar ambient temperature conditions.