Skin Hydration and Solvent Penetration Measurements by Opto-thermal Radiometry, AquaFlux and Fingerprint Sensor

The aim of this study is to develop new data analysis techniques and new
measurement methodologies for skin hydration and solvent penetration measurements
by using Opto-Thermal Transient Emission Radiometry (OTTER), AquaFlux and
capacitive contact imaging based on Fingerprint sensor, three novel technologies
developed by our research group.
This research work is divided into three aspects: the theoretical work, the
experimental work and the portable opto-thermal radiometry hardware design work.
In the theoretical work, a) an effective image retrieval method based on Gabor
wavelet transform has been developed, the results show that it is particularly useful
for retrieving the grayscale capacitive skin images; b) an algorithm based on Grey
Level Co-occurrence Matrix (GLCM) has been developed to analyze the grayscale
capacitive skin images; c) a comparison study of Gabor wavelet transform, Grey level
co-occurrence matrix (GLCM) and Principal Component Analysis (PCA) has been
conducted in order to understand the performance of each algorithm, and to find out
which algorithm is suitable for what type of images. In the opto-thermal radiometry
hardware design work, a new, low cost, portable opto-thermal radiometry instrument,
based on a broadband Infrared emitter and a room temperature PbS detector, has been
designed and developed. The results show that it can work on any unprepared sample
surfaces. In the experimental work, various in-vivo and in-vitro measurements were
performed in order to study skin hydration and solvent penetration through skin and
membranes. The results show that, combined with tape stripping, capacitive skin
imaging can be a powerful tool for skin hydration, skin texture and solvent
penetration measurements. The effect of three different parameters of Fingerprint
sensor and its detection depth are also studied. The outcomes of this work have
provided a better understanding for skin hydration and solvent penetration
measurements and have generated several publications.