  We propose an approach, called the Equilibrium Distribution Model (EDM), for
automatically selecting colors with optimum perceptual contrast for scientific
visualization. Given any number of features that need to be emphasized in a
visualization task, our approach derives evenly distributed points in the
CIELAB color space to assign colors to the features so that the minimum
Euclidean Distance among the colors are optimized. Our approach can assign
colors with high perceptual contrast even for very high numbers of features,
where other color selection methods typically fail. We compare our approach
with the widely used Harmonic color selection scheme and demonstrate that while
the harmonic scheme can achieve reasonable color contrast for visualizing up to
20 different features, our Equilibrium scheme provides significantly better
contrast and achieves perceptible contrast for visualizing even up to 100
unique features.
