THE REFLECTANCE OF HUMAN SKIN IN THE EXTENDED INFRARED REGION USING A FABRY-PEROT BASED SPECTRAL MEASUREMENT TECHNIQUE

Date

2023-9-7

Author

Dinçer Kılıç, Merve

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

96
views

73
downloads

Cite This

Understanding the optical properties of human skin is important for many current applications. Experimental studies aided by mathematical models will allow important improvements for optical bio-measurement tools. By using a novel Fabry- Perot-based MEMS type tunable wavelength filter we show that precise measurements can be performed in the traditionally hard-to-reach extended near- infrared region. Although there is a large amount of data on the optical properties of human skin in the visible spectral region, there is limited data in the extended infrared region. Of the many studied in the literature the characteristic properties of skin are not well documented in the spectral region above 2000nm due to the higher absorption of water and limitations with instrumentation. Especially for in-vivo measurements, real-time analysis is crucial to better estimate scattering parameters which can shed light on limitations of detection of various species that show resonant features in this spectral region. The approach in our study is based on using a Fabry- Perot-based MEMS type tunable wavelength filter to measure and quantify the scattering parameters of human skin in the extended NIR region. The validity of the obtained parameters is checked by applying a similar measurement scheme in the v 1550-1950nm region where multiple studies in the literature have already been performed. Using Monte-Carlo methods based on multi-layer model simulation of human skin the scattered radiation is modeled and the measurement quality is assessed. Due to the limited penetration of ex-NIR light, a 3-layer model is then used for simulating the measurements in the 2000-2450nm region, and scattering and absorption parameters are obtained for each layer. A three-layer model of skin is sufficient for modeling the observed reflectance of ex-NIR light in the 2000-2450nm region. The absorptive and scattering parameters obtained with the results agree well with other published works for wavelengths below 2200nm. This study demonstrates that devices that utilize a MEMS-based rapidly tunable Fabry-Perot-based spectral measurement technique can be applied for in-vivo studies where real-time monitoring is necessary for accurate analysis.

Subject Keywords

Monte Carlo, Skin Reflectance, Human skin, Absorption Coefficient, Scattering Coefficient

URI

https://hdl.handle.net/11511/105941

Collections

Graduate School of Natural and Applied Sciences, Thesis