JaeChul SHIN, Naoki MATSUKI, Hirohisa YAGUCHI¹ and Satoshi SHIOIRI¹

Graduate School of Science and Technology, Chiba University, 1-33 Yoyoicho, Inage-ku, Chiba 263-8522, Japan
¹Department of Information and Image Sciences, Chiba University, 1-33 Yoyoicho, Inage-ku, Chiba 263-8522, Japan

(Received October 30, 2003; Accepted January 29, 2004)

We propose a color vision model that can be used to predict color appearance in mesopic vision as well as photopic and scotopic vision. It is based on a two-stage model which consists of the cone and opponent stages and it assumes rod intrusion at the opponent stage. The model has the following features to describe the color appearance in mesopic vision. First, it includes a gradual and nonlinear shift in spectral luminous efficiency from V(λ) to V'(λ) to cope with the spectral sensitivity difference between photopic and scotopic vision and the nonlinearity of rod influence on the luminance channel. Second, the model assumes decrease of the chromatic component with decreasing illuminance to explain the reduction of saturation at low illuminance levels. Third, it assumes that red/green and yellow/blue components change with illuminance levels independently, thus explaining hue shifts with decreasing illuminance. We applied the model for color appearance simulation of natural scenes in a mesopic visual environment.

Key words: mesopic vision, color appearance, color appearance modeling, opponent-color vision model, mesopic color reproduction