Investigating Point to Point Emissivity Variation of Wounded Tissue

Infrared cameras are becoming increasingly popular in clinics. Current practices, however, often overlook the importance of emissivity when taking thermal measurements. The consensus is that human skin has an emissivity of 0.98, but this varies between individuals, areas examined and whether the skin is damaged. This research investigated the emissivity variation of chronic wounds and its effect on thermal measurements. A reflectance based method was used which alternated shades at different temperatures over the region of interest. Based on the change in the thermal images, emissivity was calculated at each pixel. It was found that wound emissivity was slightly higher than intact skin emissivity. Correcting for emissivity resulted in an average temperature difference of 0.83% in the thermal images. The difference between the original thermal image and the emissivity corrected thermal image in some cases was substantial. These differences could prove significant in clinical evaluations, indicating the need to incorporate emissivity measurement into standard protocol to ensure utmost accuracy.