We describe an algorithm that transforms a given input colormap to one that is more perceptually uniform (i.e.equal steps in data value are equally perceivable). We have incorporated the algorithm into a JavaTM application. First, the application measures a given user’s perception function for a given monitor and colormap. Then, it computes a “normalized” colormap which preserves the color ordering of the original map but modifies the positions of the colors so that the resulting colormap will be much more perceptually uniform. We present results for both commonly used colormaps and personal, “made-up” colormaps, and show the improvement that is achieved in each case. The normalized maps tend to preserve luminance linearity, within the confines of the characteristics of the input colormap. Overall discrimination is best when the original colormap incorporates both hue and luminance variation.
By: Donna L. Gresh
Published in: RC24542 in 2008
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