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24 February, 1999
b. ADS (Auto Image Density Selection)
In ADS mode, the user does not set the threshold; the machine calculates it,
guided by input from the user for F/C and 2C mode (there are 5 settings in the
"User Tools" menu).
In full color mode, after the first scanning (Bk) the machine calculates the threshold
for removing background by referring to the RGB data taken from the entire
original.
In black and white mode, the machine detects the background level for the original,
also known as the peak white level, and removes this from the image, to make a
white background. Peak level data is taken for each scan line to correct for
changes in background density down the page. From the peak white level, the
machine determines the white reference value for A/D conversion. Therefore, in
black and white mode the background density is controlled before data is input to
the A/D converter.
(3) Positive/Negative Reverse
In the positive/negative mode, colors are changed to their complements as shown.
Red ↔ Cyan
Green ↔ Magenta
Blue ↔ Yellow
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IMAGE PROCESSING
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R
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