FaceLight: Potentials and Drawbacks of Thermal Imaging to Infer Driver Stress

Driving a modern car is a complex, cognitive demanding task involving concentrated observation of the road, roadside, car and information/assistance system status, etc. Drivers are conscious about this, nevertheless, they are still operating tertiary controls, talking on the phone, smoking cigarettes, having lunch, reading maps or meeting agendas, or working on their computer. As a consequence - caused by cognitive overload and/or limited multitasking capabilities-- precarious driving situations are created. To explore the potential of thermal imaging in a vehicular setting, in particular to infer mental conditions of the driver in an unobtrusive manner, and to use this information to automatically react to a detected risky state, we have developed the prototypical interface "FaceLight" and performed a lab-based driving simulator study to evaluate the interface under conditions of varying workload. With "FaceLight" the driver can be interpreted as signal light, with a 'red face' (hot surface temperature) standing for high stress or cognitive overload while a 'green face' (cooler temperature) equals to a relaxed, stress-free mental state. Initial results revealed that this technology has potential to capture shifts in the mental state of an individual in a inattentive manner, but highlighted also that a lot of influencing factors still need to be incorporated to reliably recognize a specific state solely based on facial skin temperature (variation).