Illuminant estimation of natural scene using the sensor correlation method

This paper describes practical algorithms and experimental results using the sensor correlation method. We improve the algorithms to increase the accuracy and applicability to a variety of scenes. First, we use the reciprocal scale of color temperature, called 'mired,' in order to obtain perceptually uniform illuminant classification. Second, we propose to calculate correlation values between the image color gamut and the reference illuminant gamut, rather than between the image pixels and the illuminant gamuts. Third, we introduce a new image scaling operation with an adjustable parameter to adjust overall intensity differences between images and find a good fit to the illuminant gamuts. Finally, the image processing algorithms incorporating these changes are evaluated using a real image database.