236 ハイライトや相互反射を含んだ画像からの物体色推定

Abstract

A method is described for estimating the colors of object surfaces when the measured image contains highlight and interreflection effects. It is shown that when two objects of inhomogeneous dielectric materials such as plastics are placed close together, the observed color vectors from the object surfaces are expressed in a linear combination of the illumination color, the two object colors, and the mutual reflection color. First, we estimate the illumination color from highlight areas in the measured image. Ncxt, we estimate the object color inherent in each surface. A chromaticity plane is used to represent the chromaticity coordinates of any observed colors as a relative coordinate system on the basis of the illumination color. The problem of estimating object color is then reduced to finding two extreme points of histogram. Finally, we demonstrate the feasibility of the method in an experiment, where the object color image without highlight and interreflection is recovered.