This paper estimates illumination colors by using only a
single surface color taken under multiple illumination colors.
Past researchers have found that there is a difficulty in
estimating illumination colors using a single surface color.
However, the method presented here overcomes the problem.
Surface color is estimated by considering four characteristics
of illumination and surface color spaces. First, the
outdoor-illumination colors exist in a specific color range.
Second, multiple illuminations give constraints for the surface
color. Third, multiple illuminations also give constraints
for the color range. Fourth, each color component
affects those constraints in a different manner. Based
on those characteristics, a novel method can be designed.
The proposed method produces consistently accurate results
when multiple illumination colors are used, because
the constraint (possible range of illumination colors) on illumination
colors refines the estimated illumination ...