PROBLEM TO BE SOLVED: To accurately measure pigment concentration from a skin image without being affected by shadows formed in an image surface.SOLUTION: Absorbance spectra of a skin model containing pigments such as melanin, oxidized hemoglobin, reduced hemoglobin or the like are acquired for a plurality of cases in which combinations of each pigment concentration Ci (i=1, 2 to N) are different on the basis of a simulation model for calculating spectral reflectance from cutaneous pigment concentration. The acquired plurality of absorbance spectra of the skin model are subjected to multiple regression analysis using an absorption coefficient spectra of each pigment εi (λ) (i=1, 2 to N) as an explanatory variable to acquire regression parameters ai (i=1, 2 to N). Relational expressions between the regression parameters ai (i=1, 2 to N) and the pigment concentration Ci (i=1, 2 to N) are then acquired without using the intercept a0 of the regression parameters. Each pigment concentration Ci (i=1, 2 to N) of the skin of a subject is calculated from the regression parameters ai (i=1, 2 to N) absorbance spectra of the skin of the subject using the relational expressions.COPYRIGHT: (C)2013,JPO&INPIT【課題】皮膚画像から色素濃度を測定するにあたり、画像面内に形成される陰影の影響を受けることなく、正確に測定する。【解決手段】皮膚の色素濃度から分光反射率を算出するシミュレーションモデルに基づき、メラニン、酸化ヘモグロビン及び還元ヘモグロビン等の各色素を含む皮膚モデルの吸光度スペクトルを、各色素濃度Ci(i=1,2,…,N)の組み合わせが異なる複数の場合について求め、得られた複数の皮膚モデルの吸光度スペクトルを、各色素の吸光係数スペクトルεi(λ)(i=1,2,…,N)を説明変数として重回帰分析し、回帰パラメータai(i=1,2,…,N)を求める。この回帰パラメータai(i=1,2,…,N)と色素濃度Ci(i=1,2,…,N)との関係式を、回帰パラメータの切片a0を使用せずに求め、その関係式を使用して被験者の皮膚の吸光度スペクトルの回帰パラメータai(i=1,2,…,N)から被験者の皮膚の各色素濃度Ci(i=1,2,…,N)を算出する。【選択図】図1
