Improvement in the measurement of the thermal properties of skin using changes in the ambient radiation temperature

A noncontact method for the measurement of emissivity, thermal inertia and emissivity-corrected temperatures has been developed, in which the ambient radiation temperature is changed in a discontinuous manner. A hood incorporating a heater was used to provide the ambient radiation temperature. Otsuka et al showed that four simultaneous equations could be derived from two reference plates coated with paints of different emissivities by stepwise changing of the ambient radiation temperature. The ambient radiation temperatures before and after a change were obtained by solving these equations. However, there were difficulties in controlling the ambient radiation temperature. Although the heater in the hood was controlled by a servo controller, the temperature distribution of hood surface was not uniform in the system. To solve this problem, a new heater and new temperature controller were introduced. The heater incorporated in the hood was divided into four subheaters, with a new temperature controller for each subheater. The uniformity of the ambient radiation temperature was improved using this new system.