Thermal Perception of Skin Using Optical Projections

Abstract

The largest human organ is skin, which covers and protects the body from external objects and serves as a medium of interaction with the outside world. Having adequate knowledge about human thermal perception aids in the design of devices that interact with skin and broaden our perspective of the affecting parameters in the perception process. A thermal projector was designed based on an Optima X316 Projector which is capable of creating different thermal patterns on a surface with different intensities by use of visible light waves. Skin temperature was measured via a FLIR A325-SC thermal camera. Using these devices we were able to create thermal patterns and control the rates at which the temperature of human skin is changed. A psychophysical experiment using the setup was used to determine skin thermal sensitivity and threshold. Subjects’ skin was exposed to different thermal projections and their skin was heated at constant rates to certain degrees higher than their skin temperature. As their skin temperature was altered incrementally on each location, they stated whether they could feel the heat on their skin. The experiment showed that there was statistical significance between the rate at which the subjects’ skin was heated and whether the subjects felt a temperature change. Statistical significance was also found between the amount of exposure time prior to the instance subjects felt a change in temperature and the rate at which the skin was exposed.

Thermal Perception and Thermal Devices Used on Body Parts Other Than Hand or Face

“…can be placed flat on the skin) and that it is not necessary to pre-warm the skin before testing. A recent study by Madera et al [21] showed that also for radiant stimuli, a larger rate of change leads to a higher detection rate and shorter detection times.…”

Journal of Water and Land Development

“…This plant is designed to remove moisture from the surface of bulk materials (grains) by microwave drying, disinfection and disinfestation of the material to remove microorganisms such as bacteria, fungi, and mould [MADERA et al 2017].…”