دانلود رایگان مقاله ترموگرافی مادون قرمز از چهره انسان

Abstract

The common practice of defining operational settings for Heating, Ventilation and Air Conditioning (HVAC) systems in buildings is to use fixed set points, which assume occupants have same and static comfort requirements. However, thermal comfort varies from person to person and also changes due to climatic variations or acclimation, making it dynamic. In addition, thermal comfort in transient conditions are different from the steady state conditions, which makes the prediction of thermal comfort more difficult. Thus, thermal comfort has to be monitored over time. In this paper, we present a novel infrared thermography based technique to monitor an individual's thermoregulation performance and thermal comfort levels by measuring the skin temperature on several points on human face, which has a high density of blood vessels and is not usually covered by clothing. Unlike other methods, our method requires no continuous user input or interaction. Our results demonstrate that the monitored facial points behave differently under the heat and cold stresses and it can be explained based on the underlying vascular territories. We define two heuristics to describe the thermoneutral zone based on the observed behaviors and estimate thermal comfort for individuals with 95% confidence level. Considerable variations are observed in the thermoregulation performance and uncomfortably cool conditions metrics between the males and females. Females' thermoregulation system responses are less sensitive to the perception of warm conditions. However, similar behaviors are observed for uncomfortably cool conditions across genders.

7. Conclusions

In this paper, we presented a novel infrared thermography based technique to monitor the skin blood flow variations measured indirectly through the skin temperature on several points on human face. We selected human face because it has a high density of blood vessels and it is usually not covered by clothing. During the four days of data collection, participants were asked to communicate their comfort feedback while performing regular office activities. Our sensing system consisted of an eyeglass equipped with four infrared sensors to collect infrared radiations on four points on human face (i.e., front face, cheekbone, nose, and ear) and four temperature/humidity sensors located around the participants to monitor environmental conditions and thermal stimuli. We quantitatively studied the thermoregulatory performance, namely vasodilation and vasoconstriction, via the variations in the skin temperature under external thermal stimuli. We demonstrated how thermoregulatory performance, the behaviors of the vascular territories, can be used to estimate personal thermal comfort levels. We defined two heuristics for detecting cold and hot conditions at the individual level and searched for generalizing it across individuals.