Performance characterization of non-contact infrared thermometers (NCITs) for forehead temperature measurement

• Published in: Medical engineering & physics Vol. 93; no. C; pp. 93 - 99
• Main Authors: Sullivan, Stacey JL, Seay, Nathanael, Zhu, Liang, Rinaldi, Jean E, Hariharan, Prasanna, Vesnovsky, Oleg, Topoleski, LD Timmie
• Format: Journal Article
• Language: English
• Published: United Kingdom Elsevier Ltd 01.07.2021; Elsevier
• Subjects: Blackbody; Infrared; Non-contact; Thermometer; Blackbody; Thermometer; Non-contact; Infrared; Performance
• ISSN: 1350-4533; 1873-4030
• DOI: 10.1016/j.medengphy.2021.05.007

The ability to assess the performance of a non-contact infrared thermometer (NCIT) may be limited due to the algorithms necessary to predict a reference site temperature (e.g., oral) from a measurement of the forehead skin temperature. The algorithm not only adjusts for the difference between the reference site temperature and forehead temperature, but may also account for hardware corrections, bias adjustments and emissivity settings. These algorithms are proprietary to the manufacturer and can be unique for each device. ASTM E1965-98 (2016) is a standard test method for the evaluation of NCITs. It includes forehead thermometers; however, the algorithm must be known or an unadjusted calibration mode must be accessible. This study evaluates 6 NCIT models (10 units of each) against the ASTM standard error criterion using a blackbody source. Units were tested within the manufacturer's operating and temperature measurement range specification. A method to evaluate measurement outliers and characterize each model's performance when the adjustment algorithm is unknown is proposed. Using this method, 5 of the 6 models had a predicted error > 0.3°C. •6 models of non-contact infrared thermometers (NCITs) were evaluated using a blackbody reference compliant with ASTM E1965.•10 samples of each model were tested at 8 blackbody preset temperatures; 8 measurements were taken with each sample at each temperature.•Bench testing may not assess the error introduced by proprietary temperature correction algorithms for a specific mode (e.g. oral temperature display mode) if measurements are taken in unadjusted (“test”) mode.•Assuming the algorithm produces an accurate mean reading, results can illustrate that the variance from the mean is greater than the ASTM E1965 allowable error (± 0.3°C) .•For a single model, a specific NCIT unit may perform within the allowable error; however, in a sample size of multiple units, some may not.