Introduction to common spectra
1. RGB light: Simply put, it is the natural light that everyone sees in our daily life. R/G/B represents the three primary colors of visible light: red/green/blue. The light that everyone can perceive is composed of these three lights. Mixed, the photos taken in this light source mode are no different from those taken directly with a mobile phone or camera.
2. Parallel-polarized light and cross-polarized light
To understand the role of polarized light in skin detection, we first need to understand the characteristics of polarized light: parallel polarized light sources can strengthen specular reflection and weaken diffuse reflection; cross-polarized light can highlight diffuse reflection and eliminate specular reflection. On the surface of the skin, the specular reflection effect is more pronounced due to the surface oil, so in the parallel polarized light mode, it is easier to observe the skin surface problems without being disturbed by the deeper diffuse reflection light. In the cross-polarized light mode, the specular reflection light interference on the skin surface can be completely filtered, and the diffuse reflection light in the deeper layers of the skin can be observed.
3. UV light
UV light is the abbreviation of Ultraviolet light. It is the invisible part of the wavelength less than visible light. The wavelength range of the ultraviolet light source used by the detector is between 280nm-400nm, which corresponds to the commonly heard UVA (315nm-280nm) and UVB ( 315nm-400nm). The ultraviolet rays contained in the light sources that people are exposed to on a daily basis are all in this wavelength range, and the daily skin photoaging damage is mainly caused by ultraviolet rays of this wavelength. This is also why more than 90% (maybe 100% in fact) of the skin detectors on the market have a UV light mode.
Skin problems that can be observed under different light sources
1. RGB light source map: It presents the problems that the normal human eye can see. Generally, it is not used as a depth analysis map. It is mainly used for analysis and reference of problems in other light source modes. Or in this mode, first focus on finding out the problems manifested by the skin, and then look for the underlying causes of the corresponding problems in the photos in the cross-polarized light and UV light mode according to the problem list.
2. Parallel polarized light: mainly used to observe fine lines, pores and spots on the skin surface.
3. Cross-polarized light: Look at the sensitivity, inflammation, redness and superficial pigments under the skin surface, including acne marks, spots, sunburn, etc.
4. UV light: mainly observe acne, deep spots, fluorescent residues, hormones, deep dermatitis, and observe the aggregation of Propionibacterium very clearly under UVB light source (Wu’s light) mode.
FAQ
Q: Ultraviolet light is invisible light to the human eye. Why can skin problems under ultraviolet light be seen under the skin analyzer?
A: First, because the luminous wavelength of the substance is longer than the absorption wavelength, after the skin absorbs the shorter wavelength ultraviolet light and then reflects the light out, part of the light reflected by the skin surface has a longer wavelength and has become visible light to the human eye; second Ultraviolet rays are also electromagnetic waves and have volatility, so when the wavelength of the radiation of the substance is consistent with the wavelength of the ultraviolet rays irradiated on its surface, harmonic resonance will occur, resulting in a new wavelength light source. If this light source is visible to the human eye, it will captured by the detector. A relatively easy-to-understand case is that some substances in cosmetics cannot be observed by the human eye, but fluoresce when exposed to ultraviolet light.
Post time: Jan-19-2022
