In-vivo Skin Imaging For Hydration and Micro Relief Measurements

Submission to SC5

In-vivo Skin Imaging For Hydration and Micro Relief Measurements

H Singh1, P Xiao1,2, E P Berg2 and R E Imhof1,2


1 Photophysics Research Centre, London South Bank University, 103 Borough Road, London SE1 0AA, UK
2 Biox Systems Ltd, 103 Borough Road, London SE1 0AA, UK

Keywords
Skin imaging, hydration, micro relief, grayscale values, capacitive sensor.

The water content within human skin is very important for its cosmetic properties and its barrier functions [1]. However, to measure it is very difficult. Although there are a variety of commercial instruments available for skin hydration measurements [2], each has its limits and difficulties. We report the development of a new in-vivo skin imaging technology based on the capacitance measurement principles. It centres on a hand-held probe with fingerprint imaging array sensors. J L Leveque’s work [3,4] has also shown that with these electrical capacitive array sensors, it is possible to get information on skin hydration. The hand-held probe can access any skin sites of the human body, and can generate 2-dimensional black and white skin capacitance images with a 50um special resolution. In the images, each pixel is represented by an 8 bit grayscale value, 0~255, with 0 represent white (low capacitance) and 255 represent black (high capacitance). The image files are saved in RAW image format. Our study shows that from these skin capacitance images, we can not only get skin hydration information through image average grayscale values, we can also get information on skin micro relief. Combing these imaging results with trans-epidermal water loss (TEWL) measurement results using the closed chamber condenser TEWL method [5], we can also study the relationship between skin hydration and it barrier functions.

In this paper, we present the apparatus, measurement principles, and calculations of skin image grayscale values and micro relief values. We will also present the experimental results of skin hydration and skin micro relief images in taping stripping, immersive hydration, occlusion and moisturizing cream effect.

References

[1] P Elsner, E Berardesca, H I Maibach eds, Bioengineering of the Skin: Water and the Stratum Corneum, CRC Press, 1994.
[2] J. Serup and G.B.E. Jemec eds, Handbook of Non-Invasive Methods and the Skin, CRC Press, 1995.
[3] J L Leveque and Bernard Querleux, “SkinChip, a new tool for investigating the skin surface in vivo”, Skin Research and Technology, 9, 343-347, 2003.
[4] D Batisse, F Giron and J L Leveque, “Capacitance imaging of the skin surface”, Skin Research and Technology, 12, pp99-104, 2006.
[5] R. E. Imhof, E. P. Berg, R. P. Chilcott, L. I. Ciortea, F. C. Pascut, and P. Xiao, “New Instrument for Measuremnet Water Vapour Flux Density from Arbitrary Surfaces”, IFSCC Magazine, Vol 5, No. 4, 297-301, (2002).