A modified Beer-Lambert model of skin diffuse reflectance for the determination of melanin pigments

In skin care industry and dermatology, analysis of human skin tone is an important parameter for evaluating the current condition of the skin. Research has shown that the human skin tones are due to the combination of skin chromophores (pigments) such as melanin, haemoglobin, bilirubin and beta-carotene. Several works on skin modelling have been reported but none has been specifically developed to classify and measure types of melanin. In this research, the spectral responses of different human skin phototypes are investigated for melanin pigment (pheomelanin and eumelanin) analysis. We propose skin pigmentation model based on a modified Beer-Lambert model of skin diffuse reflectance to measure types of melanin. A clinical study involving 118 participants with different skin phototypes (SPTs) is conducted where the skin reflectance data of participants are measured using Spectrophotometer Konica Minolta 2600c. Applying the data to the proposed skin model, it was found the pheomelanin concentration is -4.6E5± 5.4E-6 moles/l for SPT III, -5.9E-5±6.4E- 6 moles/l for SPT IV, and -8.2E-5±9.8E-6moles/l for SPT V and the eumelanin concentration is 9.7E-5±7.3E-6 moles/l for SPT III, 1.2E-4±1.03E-5 moles/l for SPT IV, and 1.6E-4±1.7E-5 moles/l for SPT V. Results show that proposed model can be used for pigmentation analysis to measure melanin pigments types in skin