Quantitative Evaluation of Mental Work by Thermography

Skin temperature has a close relationship to emotional state. The anther is proposing to define skin temperature of face as an index of mental stress. Skin temperature of face is remotely measured by thermography and digital image processing. From the result of experiments, it is proved that skin temperature of nose area is closely connected with the conditions of mental work. Under such intensive mental work load as repetitive calculation for a long time, nose temperature of the worker become lower than those under usual mental load. In this experiment, relation between skin temperature and heart rate variability is also studied. As an evaluation index of mental work, skin temperature is superior to heart rate variability in some cases. Mental stress of automobile driver, as a practical applicaton, is measured and effects of displaying graphic image are observed.