High sensitivity optical measurement of skin gloss

Abstract

Abstract:We demonstrate a low-cost optical method for measuring the gloss properties with improved sensitivity in the low gloss regime, relevant for skin gloss properties. The gloss estimation method is based on, on the one hand, the slope of the intensity gradient in the transition regime between specular and diffuse reflection and on the other on the sum over the intensities of pixels above threshold, derived from a camera image obtained using unpolarized white light illumination. We demonstrate the improved sensitivity of the two proposed methods using Monte Carlo simulations and experiments performed on ISO gloss calibration standards with an optical prototype. The performance and linearity of the method was compared with different professional gloss measurement devices based on the ratio of specular to diffuse intensity. We demonstrate the feasibility for in-vivo skin gloss measurements by quantifying the temporal evolution of skin gloss after application of standard paraffin cream bases on skin. The presented method opens new possibilities in the fields of cosmetology and dermatopharmacology for measuring the skin gloss and resorption kinetics and the pharmacodynamics of various external agents.

High sensitivity optical method for objective assessment of the gloss of human skin

“…The second method is based on the number of pixels above a threshold weighted with the corresponding pixel intensity. Further details of the method are described in [7]. The gloss value calculated using the proposed method are compared with the method based on the ratio of the specular to diffuse reflection, used in traditional gloss measurement devices such as Gardner Gloss meter (Micro-Tri-Gloss) and Skin gloss meter (Courage & Khazaka).…”

“…Recently we reported a high sensitivity optical method for measuring skin gloss in the low gloss regime based on number of pixels above a threshold weighted with intensity and slope of the intensity profile in the transition region from specular spot to diffuse background [7]. We have used Monte Carlo ray tracing simulations using the LightTools software to calculate the gloss for a full range samples from 100% specular (mirror) to 100% diffuse (Diffuse standard).…”

Scanning of skin gloss by a diffractive optical element-based handheld glossmeter

“…They, respectively, lead to the specular and diffuse reflection of the incident light. Therefore, in the characterisation of skin gloss, specular or diffuse reflectance or their combinations have been used [6], among other methods. Skin gloss is also known to be significantly influenced by the surface roughness, which can sometimes be enhanced after skin rejuvenation [7,8].…”

“…In addition to the factors contributing to skin optical properties, skin gloss is also influenced by external factors such as the light source [9,10] (wavelength, intensity and polarization) and measurement geometry [6] in terms of angle of incidence. It has also been demonstrated that lowlevel laser source in the visible or near infrared region presents better light-tissue interactions, especially, in the biological medium than LEDs.…”

“…Additionally, the low angle of incidence and the smaller spot size help to achieve a more compact device. More importantly, the integration of the device to a computer also allows the scanning of some skin length [14], a feature which is an additional advantage over other devices for skin gloss determination [5,6] to the best of our knowledge. Examples of such scanned profiles are shown under the results section.…”