Thermographic device with a calibrating element for enhanced precision of human temperature measurement

Abstract

Elevated temperature of humans can be an indicator of many diseases and its measurement is therefore a common diagnostic tool. Thermographic methods allow of non-contact, fast and automated measurement. Their main disadvantage, however, is a lower accuracy than is usually required for the measurement of the core body temperature. Athermographic device with an internal calibrating element for enhanced precision measurement is introduced in this study. It is a compact device for face/eyes temperature diagnostics, which uses a micro-bolometer based infrared detector and the active calibrating element. The calibrating element is embedded in the device casing and heated to a temperature close to the body core temperature 37 °C. It allows a high precision body temperature measurement with an accuracy comparable with a thermographic measurement enhanced by an external blackbody, but it keeps the device very compact and mobile. The device and its function are described in the paper. Results of verification and calibrating experiments with a black body are presented. A fairly good standard deviation of about ± 0.2 °C is demonstrated. The mean eyes maximum temperature 35.77 ± 0.42 °C obtained by an evaluation of a long-term temperature measurement on faces of human testers confirmed accuracy and effectivity comparable with a standard thermographic devices measurement enhanced by and external blackbody.