Variation in the electromagnetic signatures of the human skin with physical activity and hydration level of the skin

Owda, AY and Salmon, NA ORCID: https://orcid.org/0000-0003-4786-7130 (2019) Variation in the electromagnetic signatures of the human skin with physical activity and hydration level of the skin. In: Proceedings Volume 11164, Millimetre Wave and Terahertz Sensors and Technology XII (SPIE Security + Defence, 2019), 09 September 2019 - 12 September 2019, Strasbourg, France.

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Abstract

© 2019 SPIE. Our recent studies in the human skin signatures indicate a strong correlation between the human skin emissivity and factors such as the body mass index, the gender, the age, and the ethnicities of the participants. The key innovation in this is in recognising that signatures from the human body enable regions of the body to be identified as skin. This will enable increased the detection probabilities of anomalies, and reduced the false alarm rates in security screening portals. This is a capability that is being demanded internationally by governments and in the UK by the Home Office Future Aviation Security Solutions (FASS) programme and the Joint Security and Resilience Centre (JSaRC). In this paper, radiometric measurements conducted on human skin in the millimetre wave band region (80-100) GHz show variation in the human skin emissivity before and after conducting physical activity (jogging) subject to the same participant. The measurements were conducted on the palm of the hand and the back of the hand skin. The measurements reveal that the emissivity of the skin is significantly lower in the rest state of the body compared with the active state by mean values of 0.088 and 0.07 for the palm of the hand and the back of the hand skin respectively. The differences in the mean emissivity values were found to be linked to the length of time exercising and the hydration level of the skin i.e. (sweat). Radiometric measurements on palms of the hand and on the back of the hand skin before and after the application of an aqueous gel indicate a strong correlation between the human skin signature and the hydration level of the skin. The mean differences in emissivity values before and after the application of an aqueous gel indicate a scatter in the range of 0.02 to 0.26. These findings suggested trends in the human skin emissivity and indicate the potential of a new non-contact passive method for remote sensing of the physical state of human beings. Understanding these signatures and variations of the human skin emissivity are very important for both security screening (anomalies detection) and medical applications (non-invasive diagnosis of human body).