*NEWS*XEROX RESTORES COLOR TO B&W FAXES

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Xerox Science Restores Color to B&W Faxes
Color Magic: Xerox Discovers How to Return The Original Color to Black-and-White Fax Images.
SCOTTSDALE,
AZ, Nov. 2005 – When a colored document is faxed on a black-and-white
machine, is the color gone for good? Not necessarily, according to
Karen M. Braun, a Xerox Corporation imaging scientist and co-developer
of the first way to encode documents so that the colors of the original
image can be recovered from a print made on a black-and-white printer,
fax or copier.
Conference Presentation
At the Society for Imaging
Science and Technology’s annual Color Imaging Conference here, Braun
and Ricardo L. deQueiroz, who’s on the faculty of the Universidade de
Brasilia in Brazil, are describing their work in a paper called “Color
to Gray and Back: Color Embedding into Textured Gray Images.”
The presentation is one of six being made by Xerox researchers at the conference this week.
Color: Gone, But Not Forgotten
Braun
and deQueiroz began with a common problem. When a color image is
copied, printed or faxed on a black-and-white device, the colors are
converted to shades of gray. Two different colors with the same
luminance – or perceived brightness – may “map” to the same shade of
gray, making it impossible to interpret the information the colors
carry. When that happens on graphics like pie charts or bar charts, two
colors will look the same and the chart loses its information value.
While
trying to figure out how to retain the information conveyed in color
graphs and pictures, the researchers looked for new ways to represent
color images in black-and-white. Their method turns each color into a
microscopically different texture or pattern in the gray parts of an
image. It makes it easy to identify colors with similar luminance
value, making the pictures more pleasing and the graphs more useful.
The
new method also had an unexpected benefit, according to Braun. “When
you map color to textures in this way, the textures can later be
decoded and converted back to color,” she said.
Thus the recipient
of a black-and-white fax could recover the colors of the original. It
would also allow colors to be retrieved from a printed black-and-white
hardcopy. Xerox has applied for a patent on the technology.
Practical Uses?
How
might the technology someday be used? In practice, the part of the
algorithms that code the colors could be integrated within the software
of a black-and-white printer so colors could be transformed to textured
grays. The decoding part of the algorithms could be part of a
multifunction system’s scanner, recovering the original colors so the
document could be switched back to vivid color for display or print.
Braun
is part of a contingent of Xerox researchers sharing their work at the
annual conference for color scientists. Others presenting papers and
tutorials are Raja Bala, R. Victor Klassen, Martin Maltz, Jon McElvain,
and J. Michael Sanchez – a group that collectively hold 88 patents in
the areas of color control, calibration, characterization and image
processing.

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November 16, 2005 at 11:27 AM