Detecting $\sim$10 mK Face Temperature Change Based on Lock-in Thermography Referencing Heartbeat

Abstract

Infrared thermography, which has widely spread particularly during the COVID-19 period, has been effectively used for research on health monitoring and emotion estimation. Nevertheless, detecting minute temperature changes with thermography is challenging as it is disturbed by not only noise but also outside temperature surrounding the object. In this study, we demonstrate detecting face temperature variation by implementing lock-in thermography using heartbeat signals as a reference. It allows us to detect minute temperature changes, as low as $\sim$10 mK, on the forehead with a commercially available thermal camera. The proposed approach enables stable measurement of body temperature variation, showing potential for non-contact emotion estimation.

Accepted for publication in SICE Festival with Annual Conference 2024 (SICE FES 2024) organized by the Society of Instrument and Control Engineers https://ieeexplore.ieee.org/document/10805151