Izumi NISHIDATE, Yoshihisa AIZU¹ and Hiromichi MISHINA¹

Division of Science for Composite Functions, Muroran Institute of Technology, 27-1, Mizumoto-cho, Muroran 050-8585, Japan ¹Department of Mechanical System Engineering, Muroran Institute of Technology, 27-1, Mizumoto-cho, Muroran 050-8585, Japan

(Received May 24, 2002; Accepted August 30, 2002; Revised August 3, 2002)

The bluish appearance of veins in the skin tissue was experimentally investigated by in vivo and in vitro spectrophotometric measurements. Color of the skin surface including the veins was quantitatively evaluated by employing color perception on the basis of CIEXYZ and CIELAB colorimetric systems. For in vivo measurements, the bluish appearance of veins was successfully estimated using a dominant wavelength, excitation purity, and color difference. Results of in vitro experiments using a simple skin tissue model demonstrated that the degree of bluish appearance depends on the vessel depth, diameter, and the blood content in the surrounding medium.

Key words: spectral reflectance, colorimetry, blood vessel, skin tissue, color appearance