Method for measuring skin hydration
View Patent ↗The methods of this invention relate to means for measuring skin hydration. The methods of this invention utilize at least two wavelengths filtered by at least two polarizers to create digital images of skin treated with personal care products. The methods are useful for demonstrating the efficacy of skin care products intended to increase skin hydration and/or protect the skin from dehydration, even when such dehydration is not apparent to the naked eye.
1. A method for measuring skin hydration comprising:
a) acquiring a first digital image of skin under parallel polarization conditions filtered at a first wavelength λ 1PP of from about 700 to about 900 nm;
b) acquiring a second digital image of skin under orthogonal polarization conditions filtered at the first wavelength λ 1XP of from about 700 to about 900 nm;
c) acquiring a third digital image of skin under parallel polarization conditions filtered at a second wavelength λ 2PP of from about 900 to about 1000 nm;
d) acquiring a fourth digital image of skin under orthogonal polarization conditions filtered at the second wavelength λ 2XP of from about 900 to about 1000 nm;
e) using a processing means, generating reflectance values for each of the four digital images; and
f) using a processing means, applying the reflectance values to the following Equation I:
-
log
(
(
reflectance
at
λ
2
PP
-
α
reflectance
at
λ
2
XP
)
(
reflectance
at
λ
1
PP
-
α
reflectance
at
λ
1
XP
)
wherein α is a parameter used to adjust to account for the amount of diffused reflected light in said parallel polarized images and is between about 0.2 and about 0.4, such that said processing means generates a fifth digital image of the skin using the output of Equation I.
2. The method of claim 1 , wherein the fifth digital image is generated before treatment.
3. The method of claim 1 , wherein the fifth digital image is generated after treatment.
4. The method of claim 1 , wherein the first wavelength is about 800 nm.
5. The method of claim 1 , wherein the second wavelength is about 970 nm.
6. The method of claim 1 , wherein α is about 0.3.