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
LIMITED DISTRIBUTION NOTICE:
This Research Report is available. This report has been submitted for publication outside of IBM and will probably be copyrighted if accepted for publication. It has been issued as a Research Report for early dissemination of its contents. In view of the transfer of copyright to the outside publisher, its distribution outside of IBM prior to publication should be limited to peer communications and specific requests. After outside publication, requests should be filled only by reprints or legally obtained copies of the article (e.g., payment of royalties). I have read and understand this notice and am a member of the scientific community outside or inside of IBM seeking a single copy only.
Questions about this service can be mailed to reports@us.ibm.com .