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Three Color Representation of Color Images

IP.com Disclosure Number: IPCOM000121558D
Original Publication Date: 1991-Sep-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 2 page(s) / 51K

Publishing Venue

IBM

Related People

Turner, DJ: AUTHOR

Abstract

By the use of a fixed, standard palette of color it is possible to display high quality RGB images without color contouring on a fixed palette display. The programming technique employs the same principle as that of a conventional color cathode ray tube in which three primary colors can appear to blend over a full color range.

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Three Color Representation of Color Images

      By the use of a fixed, standard palette of color it is
possible to display high quality RGB images without color contouring
on a fixed palette display.  The programming technique employs the
same principle as that of a conventional color cathode ray tube in
which three primary colors can appear to blend over a full color
range.

      First, the palette of the display device is loaded with three
linear color scales.  One from black to pure red, one from black to
pure green, and one from black to pure blue. The size of the color
scales is dependent on the overall size of the palette.  On a display
with 256 palette entries, good results have been achieved using 192
entries (i.e., 64 entries per color scale).  This one palette will
work for all images.  The video image is put on the display in the
following manner:
                Rows 0, 3, 6, 9 ...

      The red component of the first pel is extracted and scaled to
match the palette range of reds, and is plotted. For the next pel the
green component is used, and blue is used for the next.  This
sequence of R-G-B is repeated for the row.
     Rows 1, 4, 7, 10 ... are processed as above, except the order is
now G-B-R.
     Rows 2, 5, 8, 11 ... are processed as above, except the order is
now B-R-G.

      This processing creates a matrix of colors on the display with
the following repeating pattern:
           R G B
    ...