PROBLEM TO BE SOLVED: To improve the explanatory coefficient of regression parameters and to improve the accuracy in measuring the pigment concentration when the pigment concentration in the skin is measured by multiple regression analysis of absorbance spectra.SOLUTION: An effective absorbance coefficient spectrum εi(λ) of each pigment is found by analyzing main components of a plurality of absorbance spectra with different pigment concentrations of the skin. The absorbance spectra of the skin containing a plurality of pigments with different combinations of concentrations Ci (i=1, 2, ..., N) of respective pigments by a simulated model of the skin containing the plurality of pigments, and by multiple regression analysis of the effective absorbance coefficient spectrum εi(λ) of each pigment as an explanatory variable, a plurality of combinations of regression parameters ai and intercepts a0 thereof in formula (1) are found, and further formula (2) is found. By using formula (2), the pigment concentration of the skin of a subject is found from the regression parameters and intercepts thereof of the absorbance spectra of the skin of the subject.COPYRIGHT: (C)2014,JPO&INPIT【課題】吸光度スペクトルを重回帰分析することにより皮膚中の色素濃度を測定するにあたり、回帰パラメータの説明率を改善し、色素濃度の測定精度を向上させる。【解決手段】皮膚の色素濃度を変化させた複数の吸光度スペクトルの主成分分析により各色素の実効吸光係数スペクトルεi(λ)を求めておく。複数の色素を含む皮膚のシミュレーションモデルで各色素の濃度Ci(i=1,2,…,N)の組み合わせを異ならせた複数の色素を含む皮膚の吸光度スペクトルを求め、それを前記各色素の実効吸光係数スペクトルεi(λ)を説明変数として重回帰分析することにより、次式(1)の回帰パラメータai及びその切片a0の組を複数求めさらに次式(2)を求めておく。式(2)を用いて、被験者の皮膚の吸光度スペクトルの回帰パラメータ及びその切片から被験者の皮膚の色素濃度を求める。【選択図】図1A
