Thermal compensation of the IR camera for skin temperature measurement. (a) Measured skin temperature for subjects at 2 m. Different colors represent different ambient temperatures. (b) Skin temperature for subjects measured from 2 m to 5 m. Measured temperatures for each subject are translated vertically and grouped by ambient temperature. For the same subject and ambient temperature, measured temperatures in (a) represent the same data as the scaled temperatures in (b) at 2 m. (c) Effect of ambient temperature on the relationship between the measured temperature and the distance. (d) Dimensions of the face bounding box vs. subject’s distance. (e) Measured and compensated skin temperatures for one subject. (f) Error analysis of measured skin temperatures and compensated skin temperatures for all subjects at 5 m. Data for 5 m at 19°C is imputed from the line of best fit.