A Road Map to Absolute Color Appearance Pictures

Abstract

　Colors of real objects were hardly captured and reproduced using any present imaging system. Although color management technologies will compensate differences among a variety of imaging equipment, they do not necessarily reproduce exact colors of real objects.

　If spectral reflectance of a real object and spectral radiation of an illuminant are known, exact colors will be reproduced. However a color picture that includes spectral reflectance information for each pixel is hardly captured. Meanwhile, there is an emerging technology named ‘multispectral imaging,’ which will estimate reflectance spectra of skin and mucosa from a picture taken by a three-band digital camera. We applied this technology to develop an imaging system for absolute color appearance pictures, which will capture and reproduce exactly the same color as real lesion of skin and mucosa and succeeded in solution of major technological problems encountered.

　However, stable color reproduction has not been achieved by subjective tests at present. A great influence of chromatic adaptation of human eyes to color appearance of skin and mucosa was revealed through investigation of the cause of that instability.