Study On Skin Detection System Based On LED-induced Fluorescence Spectroscopy Technology

Cosmetic industry is rapidly developing with the development of social economy, and people's persuit of beauty is becoming more and more strong. Customers and industrial community have more and more demand on skin detecting instruments. The detection instruments for skins before are generally industrial-grade or professional measurement equipments, which have high precision, but are very expensive. These equipments usually supportdifferent functions with different probes, and have complex operation requirements, which is not suitable for general users; As for Consumption level skin detectors, they have some market share due to their low cost and convience of use, but they have some shortcomings such as low accuracy and limited functionality. Based on this background, we try to develop an optical based detection instrument for skins to fill the market blank, which is nondestructive, fast, small, intelligent, and faces to the public.Using the portable, stable LED-induced fluorescence spectroscopy technology, combined with Modeling and analysis method of stoichiometry, we design a nondestructive testing system based on spectrum detection and analysis. The system uses safe, high power,380nm-LED as excitation light source. The collected fluorescence spectra are evaluated by multiple linear regression technique and skin characteristic parameters model. The paper aims at the whiteness, elasticity and moisture of skin characteristic parameters. Volunteers experiments are carried out by more than two hundred person-times of more than 50 people. In the experiments we take skin fluorescent signal detections for human faces and designated parts of forearms. Cross validations of the results are taken finally. The experiments show that the relative error is<3% for whiteness,<5% for elasticiy and-10% for moisture. Validity of the system for skin parameter detection is confirmed. Considering that the moisture measurement results are not as so good, we add another round of volunteer experments, and compare them with commercially available moisture tester. The results show that that the relative error for moisture with our method is about 26%, which is still betterthan the existing equipments on the market.In addition, we also carry on the preliminary productizing work, and invest effort in the structure design and user oriented software writing. In order to be suitable for general users, we simplify the structure of this detection instrument and design a miniaturization encapsulation to make it small and cheap.The size of system main part except an external optical fiber sensing probe is 65�50�47mm,. For the convenience of the user, we also provide a application software. The software framework and interface are completed, and can be put into use as soon as the system is completed and the the practical calculation model is obtained. At present, the system is still in the further research and development, the following work will be mainly focused on improving the accuracy of water measurement, cooperating with more partners for more actual measurements and compressing the cost of the system.