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<article article-type="research-article">
  <front>
    <journal-meta>
      <journal-id journal-id-type="aggregator">72010350</journal-id>
      <journal-title>Color and Imaging Conference</journal-title>
      <abbrev-journal-title>color imaging conf</abbrev-journal-title>
      <issn pub-type="ppub">2166-9635</issn><issn pub-type="epub"/>
      <publisher>
        <publisher-name>Society of Imaging Science and Technology</publisher-name>
        <publisher-loc>7003 Kilworth Lane, Springfield, VA 22151, USA</publisher-loc>
      </publisher>
    </journal-meta>
    <article-meta><article-id pub-id-type="doi">10.2352/CIC.1993.1.1.art00044</article-id>
      <article-id pub-id-type="sici">2166-9635(19930101)1993:1L.178;1-</article-id>
      <article-id pub-id-type="publisher-id">cic_v1993n1/splitsection44.xml</article-id>
      <article-id pub-id-type="other">/ist/cic/1993/00001993/00000001/art00044</article-id>
      <article-categories>
        <subj-group>
          <subject>Articles</subject>
        </subj-group>
      </article-categories>
      <title-group>
        <article-title>Color Palette Reduction and Enhancement Techniques</article-title>
      </title-group>
      <contrib-group>
        <contrib>
          <name>
            <surname>Trenchard</surname>
            <given-names>Michael E.</given-names>
          </name>
        </contrib>
        <contrib>
          <name>
            <surname>Riedlinger</surname>
            <given-names>Lancelot M.</given-names>
          </name>
        </contrib>
        <contrib>
          <name>
            <surname>Myrick</surname>
            <given-names>Stephanie A.</given-names>
          </name>
        </contrib>
        <contrib>
          <name>
            <surname>Gendron</surname>
            <given-names>Marlin L.</given-names>
          </name>
        </contrib>
      </contrib-group>
      <pub-date>
        <day>01</day>
        <month>01</month>
        <year>1993</year>
      </pub-date>
      <volume>1993</volume>
      <issue>1</issue>
      <fpage>178</fpage>
      <lpage>180</lpage>
      <permissions>
        <copyright-year>1993</copyright-year>
      </permissions>
      <abstract>
        <p>The Naval Research Laboratory's Map Data Formatting Facility is developing a seamless, compressed, digital database of the world called the Compressed Aeronautical Chart (CAC). The CAC consists of scanned, aeronautical chart images. The CAC's primary purpose is to support
 Navy and Marine Corps aircraft mission planning and digital moving map systems. However, other users on various platforms have expressed interest in using the CAC. Therefore, the CAC must be capable of adapting to the graphics capabilities of other platforms.The CAC uses a set of custom
 color palettes that consists of 240 distinct colors. Each pixel from the precompressed data at full color (24-bit) indexes to its closest color palette entry as decided by its Euclidean distance. Custom color palettes tend to maintain color integrity between the CAC and the original data.Since
 graphics capabilities vary from platform to platform, the ability to reduce and remap a color palette is a useful tool. This paper describes the technique chosen to remap the CAC color palettes to the desired, reduced set of colors. An enhancement technique that uses a contrast stretch algorithm
 is also described. The enhancement is achieved by first calculating a given palette's luminance (Y) values. Then, a ratio of the contrast stretch luminance to the original luminance value is derived for each color in a given color palette.</p>
      </abstract>
    </article-meta>
  </front>
</article>
