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(2)
Error diffusion
This is a way of producing halftone (Pseudo grayscale) images with white and black pixels.
Optical density of pixels and its adjacent pixels are totaled and black pixels are repositioned in
the order of density in accordance with relations between adjacent pixels.
This scheme aims to minimize errors between scanned density and printed density on the
average. Density data of adjacent pixels are modified by diffusing errors on the objective pixel
into several pixels to be binarized. This scheme is aimed to keep high levels of grayscale and
high resolution, producing high quality halftone. Especially when dotted halftone images like
photos on the newspaper are scanned, this scheme suppresses moire patterns.
Following parameters are available for this function
The parameters which affects the Halftone image are shown in Table 3.8.
Parameter
Halftone reading ON
Error diffusion ON
Density *1
8 step setting ON
Set from operator panel
Light
to
Normal
to
Dark
256 step setting ON
Light
to
Dark
Contrast
Mostly soft contrast
to
Normal
to
Mostly sharp contrast
*1
Effective only for Built-in pattern
Table 3.8 Parameters of Error diffusion
Control register No.
A#2/B#2
A#19/B#19
A#19
A#1/B#1
A#19
A#20/B#20
A#21/B#21
3.2 Basic image functions
value
Default
B'xxxx11xx'
ON
B'xxxx100x'
B'xxxxxxx0'
Set from
B'xxxx00xx'
operator
B'xxxx1000'
panel
to
B'xxxx1100
to
B'xxxx1111'
B'xxxxxxx1'
X'01'
to
X'FF'
X'01'
to
X'80'
X'80'
to
X'FF'
3-11
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