A method to estimate correlated color temperature of illuminant using color video camera

The authors describe a novel, indirect method for estimating the correlated color temperature of illuminants by using a color video camera and a set of several known color chips. The video camera can have arbitrary shooting chromaticity characteristics; however, it should be used in fixed white balance. The correlated color temperature of the light source illuminating the color chips is estimated. Using the method of least squares, an accuracy from 0.1% to 1.4% is achieved, depending on the spectral distribution of the illuminants. The method fully utilizes microcomputer capabilities in acquiring the camera outputs, solving a set of simultaneous linear equations, and searching for the nearest (U, nu ) coordinate values on the black-body locus.<
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