A method to estimate correlated color temperatures of illuminants using a color video camera

An indirect method of estimating light source color or the correlated color temperature of illuminants is proposed. It incorporates a color video camera with fixed white balance, a set of known color chips, and a desktop microcomputer. The correlated color temperature of the light source illuminating the color chips is estimated. The mathematical method used is the estimation of functions to be integrated from several values of the definite integrations. These values, which are measurable, are given as the output of the color video camera under different conditions. By means of the method of least squares, estimation accuracies of from 0.1 to 1.4% of the correlated color temperature are achieved. The accuracy achieved depends on the spectral distribution of the illuminants, except for illuminants like fluorescent lamps