Fever screening systems

This method is mainly used at control gates or where crowd screening is not possible. From a closer distance you can measure exactly the temperature of the Medial canthus (tear duct) which provides the strongest correlation between outside skin temperature and core body temperature.

The IR camera is monitoring a crowd of people at once or sequential. Assuming that the majority of the measured maximum head temperature values are coming from healthy individuals the exceptions with an elevated body temperature can be easily detected.

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 0 °C to 50 °C.

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 450i 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 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.